Longevity / Fasting Works Best When It Respects the Body Transcript

Fasting Works Best When It Respects the Body Transcript

Timestamps link directly to the source video.

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Hey everybody, welcome back to the Diet Doctor podcast. I'm your host Dr. Brett Scher. Now today is part two in our two-part series on intermittent fasting and time-restricted eating. Part one was an interview with Dr. Sachin Panda. So if you haven't heard that, I recommend you go back to that one where we really get into the science behind time-restricted eating. Now in this part, part two, we're going to get more into the clinical aspects of it by speaking with doctors Kevin Hallberg and Steve Phinney and nurse practitioner Cynthia Thurlow. And with them we're going to really get into the nitty-gritty of the the pros and cons of intermittent fasting and time-restricted eating, the clinical points to really help you with success, and what some of the concerns are as you know Dr. Steve Phinney is very vocal about hold on, let's not get too fast on this fasting bandwagon until we have more science to back it up, and some of the concerns. So I'm really appreciate his viewpoint at the end. And then of course with Cynthia talking about women in particular, and the specific considerations we need to have for intermittent fasting with women. So this is a jam-packed episode with lots of good tips for you to take away and start potentially applying to improving your success with intermittent fasting and time-restricted eating. So Let's hear from Dr. Kevin Hallberg. Now Dr. Hallberg has an amazing personal story which he has transformed into a professional story. So he is a family

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medicine physician who is now board certified in obesity medicine and is making the has just made the transition to focus 100% on weight loss medicine within his medical group in Massachusetts. And he lost 125 lb in 18 months. He had sleep apnea, type 2 diabetes, hypertension, fatty liver, and by switching to a low-carb diet with intermittent fasting and time-restricted eating was able to reverse all those chronic medical conditions and lose 125 lb. And as part of his journey, he wrote a book Fasting While Furious. He's very active on Instagram and Twitter at Kevin Hallberg g e n d r e a u. I definitely recommend checking him out and following him. But let's hear what he has to say about the clinical side of working with patients with intermittent fasting and time-restricted eating. Well Dr. Hallberg, it's it's great to have this opportunity to speak with you because we just heard about your amazing story and your personal transformation. And now how you've transformed your practice as well to full-time obesity medicine. And you have used intermittent fasting both for yourself and for your patients. So first I want to hear kind of what role do you think intermittent fasting played in your remarkable health transformation? Thank you so much for having me on. I'm a huge fan of your show and your website, you know, dietdoctor. com is is a resource that I share with every single patient that I see in the office. So it's like such an honor to be here and join you know these other guests that you've had on the

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podcast. So thank you for that. Um Fasting is definitely something that's very personal for me. I did go through a weight loss journey of my own back in 2016. I lost 125 lb in 18 months. And my very first intervention for the weight loss was switching to a low carbohydrate clean eating diet. And so my starting weight was 306 lb and I slowly went from 306 down to about 230 lb. Um ultimately I decided to read the book The Obesity Code by Dr. Jason Fung who's been a guest of your podcast and is very well known in the fasting community. And after reading his book, I was able to incorporate intermittent fasting time-restricted eating into my lifestyle quite easily actually. I I did an 18 to 6 fasting ratio most days and was able to go from about 230 lb down to 180 lb. And I continued to do my low-carb approach to weight loss at that time. So really it was a combination of the intermittent fasting plus low-carb. And I used that tactic to really help my patients now lose weight in the obesity clinic. So I was practicing as a family family physician for the past 4 years and recently transitioned to full-time weight loss medicine where I

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work alongside bariatric surgeons helping patients pre-op and post-op lose weight and then also helping some patients avoid surgery altogether with weight loss. Yeah, so I mean it's so much so powerful when you can talk to a patient and say this is what I did. Look what I did. You know the old saying walk the walk, talk the talk and all that. And you obviously did that. But not everybody is is going to make that same transition that you did to go low-carb first and then intermittent fasting, although it's clearly a very effective approach. So when you're working with patients, do you see a difference in I guess both success and compliance and sustainability for those who go low-carb first and then intermittent fasting or those who just try intermittent fasting no matter what their baseline diet is? That's such a great question because as a weight loss doctor, you do have a lot of patients who come to you with preconceived notions and and things that they want to try right away. Like they'll come to you with your first visit and they'll say, I would really like to leave here with a medication or I would really like to start an intermittent fasting regimen. And so it does matter the order that you do things a little bit when it comes to success. It seems to be that if you start a low-carb clean eating approach first and you do dietary changes first, um the intermittent fasting just seems to follow and it's actually just kind of a natural progression for most people. I didn't even realize that it was you know happening to myself while I was losing the weight. And I I noticed that

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I was just eating in an 8-hour window on my own without having even read The Obesity Code without even knowing much about intermittent fasting. And so I do like that order when I'm advising patients. I tend to tell them to clean up their diet a bit, try to minimize or eliminate even processed foods, and I encourage them to eat things like berries and vegetables and meats and nuts and full-fat yogurt and eggs. And then you know, down the line sometimes not even in the first visit together we'll incorporate intermittent fasting as another tool to push the weight loss further, particularly if they hit a plateau like I did myself. Yeah, so it sounds like you you advocate dietary changes, food changes first, and then timing and intermittent fasting second. But you brought up a wonderful point that when you make a change in the foods that you're eating frequently, the intermittent fasting at least the time-restricted eating just becomes naturally. And I think this is an interesting point to make because sometimes when people hear the word fasting, it's just such a it's got such a connotation to it and people think hunger and sacrifice and uncomfortable and like why would I want to do that? But the time-restricted eating part, which is certainly part of intermittent fasting, can come natural and can just feel like like you're not even thinking about it. So how do you sort of work around the the concept of fasting versus time-restricted eating? And when do you think it's appropriate to add in longer fasts that may be a little uncomfortable, a little more challenging versus just sticking to the time-restricted eating that can come

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naturally for so many people? Great question. So I don't have a specific rule for my patients for how long I think that they should fast for. I have such a variety of patients that I see from other physicians to nurses to super busy professionals like lawyers and stay-at - home moms. I mean there's like everything in between. So there's people with all different types of schedules. And so what I say for for intermittent fasting and time-restricted eating in general is do what works for you. There's quite a bit of patients that I work with who will do a 12-hour fast, a 14-hour fast, which doesn't seem like much, but has I mean it has been shown to show some benefit with in terms of insulin sensitivity, you know, improving insulin resistance. So I just think the best intervention is really just what works with your schedule and what works with your preferences. So if you're already on a low-carb diet and losing weight, but you want to you know progress that a little bit further, just adding in a 12-hour fast as a you know as a scheduled thing where every every night you fast from from say 7: 00 p. m. to 7: 00 a. m. the next morning. Or maybe you're a super busy professional who can only eat in a 4-hour bracket of time like 4: 00 p. m. to 8: 00 p. m. is kind of your eating time every day and you want to make sure that you get to have dinner with the family every night. So really it's just schedule dependent and what you can do whatever you can to incorporate it into your schedule. Other people will do one

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or two 24 or 36-hour fasts in during their work week. Typically I tell people, you know, don't fast beyond 36 or 48 hours without talking to me first. I don't really get too much into the extended fasting. I know that Dr. Fung does that with the fasting method, but I typically tell people 12, 14, 16, 18-hour fast. Quite a few of my patients are on one meal a day fast where they they frequently fast for you know, 23, 24 hours at a time. But when it gets to beyond the 36-hour mark, you know, of extended fasting, 2 days, 3 typically I don't follow people in that way and advise them to do that. Why not? I guess my biggest concern is follow-up. So our patients have follow-up appointments with us on a 4 to 6 week basis and then they follow up with our um dietitians on like a 1 to 2 month basis. And then we also have other staff that helps with certain things like um binge eating disorders, emotional eating, um history of eating disorders in general. Um so we have social workers and therapists that help with that. They're licensed clinical social workers. So they'll see patients on a 1 to 3 month basis. And so um I I find that if you're going to go past the 36 48 hour mark, maybe 72 hours or beyond, you need a closer follow-up than once per month. Yeah. And and I think that is important to differentiate the longer fast from the shorter fast and time

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restricted eating. There really does seem to be like a line in the sand sort of where the risks and the complications and the challenges start to rise. And it's sort of unclear how much the benefits also rise. So I think that's really I think that's a great point that the sweet spot is more in the time restricted eating in the shorter fast. So you you brought up the eating disorders and that's another um sort of controversial topic when it comes to fasting and time restricted eating. So do you have concerns about using intermittent fasting or time restricted eating in patients who have a history of these eating disorders? Certainly. So during our first visit together, I always make sure to bring up history of eating disorders and I typically will describe some common eating disorders like binge eating disorder for example since it's the most common among both men and women in the US. And um I'll describe that to my patients and see if any of it resonates with them because intermittent fasting is okay for the vast majority of patients, but if you have a history of something like, you know, severe emotional eating or anorexia or bulimia or binge eating disorder, it may not be right for you. Um particularly someone who is has a history of anorexia, maybe being underweight, being malnourished, it might not be the best option for them, you know, to lose an extra 5 lb or something like that. Like if they're already in the normal weight bracket for their height, um it's probably not the best intervention. And then someone who tends to binge may unfortunately get so

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hungry at the 18 20 24 hour mark that they make bad decisions. So it could still work and I personally have a history of binge eating and still make intermittent fasting work for me, but it's just something where it's like that extra layer of risk and it's something that we have to cover and discuss and really explore um patients' feelings about about that. Yeah, I love that you make that a priority to describe that ahead of time and and to describe what the you know, binge eating disorders or emotional eating disorders can look like because they may not feel like they're labeled as a binge eater and emotional eater, but when you describe it, it may start to sort of ring true and it sort of prepare them for that. And that's something that you don't necessarily get if you just re you know, see somebody on the internet talking about intermittent fasting and say, "Oh, I should try this." And in my experience is that the people who kind of fail or don't do well are exactly those people who sort of make up for it by binging um after their fasting. And and they wouldn't know that they're at risk for that unless they had someone counsel them or at least bring it up. So I think it's so important that you bring that topic up and that that is great. But once you establish that that they have that, does it mean fasting's off the table or does it mean you can still do it just with certain precautions and what might those precautions or those other interventions be? So I think if your if you have a history of binge eating tendencies, emotional eating issues, um maybe even possibly a history of bulimia like a remote history many years prior, it's still possible to do

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something like intermittent or time restricted eating on a 16 to 8 or an 18 to 6 schedule. Um I think it's really more extended fast, 24 hour fast and beyond that people should watch out for that we should watch out for with a history of eating disorders. I think um I've had several patients who actually, you know, meet the criteria for binge eating disorder and they are still able follow an 18 to 6 schedule with no problem and when they do tend to cheat and make a mistake, they do, you know, forgive themselves and I teach my patients a lot how to forgive yourself, how to love yourself. And so um I think like the the rebound from that mistake that you make matters just as much as the mistake itself. So um people tend to get off track for an entire weekend or an entire week or even an entire month after they slip up at a wedding or an an event like a party. So I try to teach my patients to take it like one day at a time and don't, you know, say that the whole weekend is ruined or the whole month is ruined because of one little slip-up. It's just part of the, you know, part of the weight loss process. We're not perfect. Such such an important point, the whole emotional side of things and the internalizing of the, you know, I did bad. I I am bad. That sort of internalizing that message. Um which I'm guessing you didn't learn that in medical school, did you? No. We barely had nutrition classes. It was like 4 hours out of 4 years. Yeah. So when you think back to your own

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journey and your own challenges, here as a physician to, you know, get into the sort of health problems that you got into and get yourself out of it with fasting as part of that. I mean, fasting is still not really I I guess you could say not really well accepted in in medical practice as a whole. But what about within the obesity medicine? Like is it starting to become more accepted? Are you seeing it among colleagues that that it's being talked about more or is it still sort of thought of as fringe and dangerous and maybe we shouldn't do it? Yeah. So in our clinic where we work alongside the bariatric surgeons, we have three MDs who are all um obesity medicine certified by the American Board of Obesity Medicine, ABOM. Um and we have two nurse practitioners working with us. And actually all five of us, all five providers, do follow um low carb recommendations for our patients and we also use intermittent fasting to some degree. Um none of us really work with patients where we're encouraging them to fast beyond like 36 to 48 hours, but almost all of us do time restricted eating and we've all noticed that it's just a natural progression. When you start low carb and your body starts starts to become fat adapted, you're just less hungry and so patients will bring it up on their own anyway. And so a lot of us, you know, we're all on board and I think obesity certified physicians um are starting to become on board as a unit, but I think it's going to take time for

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like the general medical establishment to be on board even with just low carb, never mind the intermittent fasting in addition to that. Um I still have cardiologists and endocrinologists giving me bad feedback about starting patients on low carb diets and telling me that, you know, Mediterranean would be a better way to help patients lose weight. And so we've kind of had to like finagle our wording a little bit and say, "Oh, it's low carb Mediterranean that we're starting patients on."and avoid the K word which, you know, like keto is practically a swear to some specialists, unfortunately. Sure. So it takes time to change minds, you know, and um the American Diabetes Association recently coming out with that low carb diet as an option for helping improve um you know, insulin sensitivity and diabetes control helps a lot. We need more bodies of medicine to support low carb plus intermittent fasting. Yeah, so it'll be interesting to see if some of these governing bodies come out and start um promoting time restricted eating or intermittent fasting or, you know, timing of your meals, however they want to word it to take the sting out of it. Right again, intermittent fasting may have too much of a sting right now for for a certain, you know, governing bodies and certain guidelines, but but you could word it as just timing of your meals or spacing out the timing a little bit or time restricted eating. Like all those should be perfectly acceptable, although maybe they're they're still not. But do you have concerns about some potential side effects or risks for people even with time restricted eating, whether it's an 18 6

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or or an OMAD, you know, lean body mass concerns um uh or malnutrition concerns or anything like that? I think if someone has a history of malnutrition or issues with electrolyte abnormalities for example or like recent unexpected weight loss, there are reasons to not start um time restricted eating, but I don't have much in the way of concerns in general. I think most people in the general population, men, women, um it's very safe to do something like time restricted eating 16 8 or 18 6 and the vast majority of patients, even people on medications, can do it. Um I would say it really only is if you're going past the, you know, 24 hour mark that it matters if you're taking medications that require food intake like like iron or aspirin or metformin or insulin. So those patients need a little bit of, you know, extra care and extra concern for things like that. And there's also other comorbidities like type 1 diabetes that may need to be watched a little bit closer when it comes to fasting. But I think that's really more prolonged fasting. I think shorter intervals and time restricted eating is safe for the vast majority of people. I would say pregnancy, um children under 18, breastfeeding, um those are kind of the only things that are hard stops for me in the clinic. We do see adolescents um you know, ages 13 to 17 and I don't do any kind of time restricted eating with them. I focus more on clean eating and getting rid of processed foods which

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seems to be the main problem with teenagers. So Yeah. I'm sure. Yeah, I think those are all great points for people to to sort of hear and and if they are in one of those groups, don't start this on your own, but consult with an expert like yourself to to see if there is a place for it because again, people sometimes people want the quick fix, right? So, the quick fix used to be and and still is unfortunately medications and pills, but I think some people maybe see intermittent fasting as a quick fix also, but it's not always the case. It has to sort of fit into a whole program. Do you see it so similarly? Yes, that's true. So, I think people look at intermittent fasting, specifically longer fasts as a quick fix. So, like I want to get rid of these 10 extra pounds, so I'm going to fast for 5 days or 7 days or 10 days, but I like the slower longer approach where we work with people on fixing their nutritional habits and having them eat cleaner foods and then let the intermittent fasting follow on more of a schedule where it's like 1 day a week I'm fasting for 24 hours or every day I eat between 2: 00 p. m. and 7: 00 p. m. You know, so I like, you know, more of a schedule and more of a predictability and that way you're not binging on the weekends, on tons of processed carbs and then restricting yourself for 3 days, which is almost like a bulimia cycle where it's kind of just that's I mean, it's not quite disordered eating, but it's like almost there where you're using the fasting to negate all of that food that was terrible that you just ate the the few

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days prior. So, it's hard. It's a fine line, but I I usually tell people to try to incorporate it at first, you know, 12 hours, 14 hours and you can progress from there and maybe get to that 18-hour mark cuz we know that, you know, autophagy really happens between 12 16 plus hours. So, if you can get to the 18-hour mark for fasting, I usually say that that's pretty good and people can maintain that over time in their schedule. Most people can do, you know, a 6-hour eating window every day. Yeah, so that that's interesting. I mean, this whole topic of autophagy or autophagy, like when does it kick in and how do we know? And and the science behind that I think is very difficult to interpret and apply to humans to know where that threshold is and people want to know like the effective minimum dose, right? If you knew that 16 hours was the minimum dose that was where you hit the sweet spot, then most people wouldn't fast for 17 or 18 or 20 hours, right? They want the minimum effort for the maximum benefit. So I guess you're saying you believe that is right about the 16-hour mark. Yeah, so that's so I I tell people to start with 12 hours, 14 hours, but if we can get them to the 16-hour mark, 18-hour mark, I feel a little bit better about it and I've seen more success with that in clinic. That's just anecdotally. That's not like I don't have numbers to prove it. I'm not like a research scientist with all this data. I just tend to to focus on like a 16 to 18-hour fasting window and if people can only do 12 or 14 and that works for them and they're eating low carb and losing weight, then that's totally fine, too. I

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tend to not like push a specific number, but really I think the greatest success that I've seen has been 16 to 18 hours for fasting. I I sort of asked you this before, but I want to ask it a little more pointedly now. Do you have to eat low carb to succeed with intermittent fasting? I think it's the most successful I mean, it's the best combination there is, but I think it is possible to eat carbohydrates and fast and lose weight. I just think it may take longer. If you look at certain certain cultures and groups of people, they're able to eat things like rice and beans and incorporate intermittent fasting and still lose weight. So, I think it is possible, particularly if the foods that you're eating that are carbohydrate containing are complex carbs or certain grains that are, you know, naturally occurring and not processed. So, I think it's possible. I just think the best combination is a low carb diet. Usually we focus on 40 g, 50 g or less per day of carbohydrates plus the time restricted eating. So, one last question for you and this is a question that so many people ask when they're getting started with intermittent fasting or time restricted eating, what can I have? What is considered okay for a fast and what's going to kick me out of the fast? Do you have advice for people on that? Yeah, you know, that really is the most common question. I think every single patient who comes to see me and we talk about time restricted eating, they want to

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know what they can have while fasting and so in general, I tell them the cleanest fast is just a water fast with nothing in the water, no additives, no fake sweeteners, but many people have so much success with tea, with coffee as long as there's no sweeteners, with things like bone broth, so chicken broth or beef broth. Sometimes people will have a bit of pickle juice. Sometimes people will put a little salt in their water. And so, overall, as long as you're keeping it under 35 calories during your fasting window, you should be good. And I also think it's important there are many products out there. Crystal Light is just one example where they're technically zero carb, zero sugar, zero calorie, but they may elicit some kind of response when it comes to your body's hormones like insulin, for example. So, those things are really also important to stay away from during your fasting period. Yeah, it's interesting. Even if it has no calories, one thing it can do is sort of make it more challenging cuz it can trigger insulin and glucose swings or hunger or cravings and it can make it harder just to comply with the fasting, let alone what it does to your your home hormonal changes, which may counteract what you're trying to do with the fasting. So, that's a good point cuz a lot of people think as long as it's zero calories, it's clean, but that's a that's an excellent point that you bring up that we have to be a maybe a little more concerned about even some of those. So, well, thank you. I really appreciate you taking the time and joining us today. Thank you so much

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for having me. Next, we're going to hear from Cynthia Thurlow. Now, Cynthia is a nurse practitioner and the CEO and founder of Everyday Wellness Project. She's a a international speaker including a couple popular TED Talks and she focuses on a lot of that has to do with wellness, but also specifically intermittent fasting. But specifically intermittent fasting for women. Now, a lot of times we hear of intermittent fasting as if it's one thing, you know, one protocol, one way to do it, but that's definitely not the case. And as we're going to hear from Cynthia, not only do we have to, you know, worry about or consider lots of different things about intermittent fasting, but we also have to consider its role according to your gender. And not just man or woman, but when you're a woman, what age are you? Where are you in sort of your menstrual cycle? And all of these things will play into how intermittent fasting may affect your body and how you may be able to comply with intermittent fasting. So, Cynthia, you speak a lot about the differences of fasting for women. So, give us an overview of what you see as the main differences and some of the similarities that you have to consider when speaking to a woman to try and get them interested in fasting and involved in fasting for health benefits. I think that's a great question and and I always like to start off by saying, you know, women are not mini men. So, we have to approach fasting a little bit differently. Most of that is is due to our menstrual cycle and the impact of fasting on where we are in our cycle, whether we're

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in the follicular phase or the luteal phase, how close we are to menstruation. That is absolutely paramount because our bodies are designed to be able to procreate and carry a healthy pregnancy and for that reason, we are much more sensitive to hormetic stressors, whether it's like finding that Goldilocks effect of not too much, not too little beneficial stress. And so, fasting is something that I look at as a beneficial stress if in the right amount at the right time. And so, when I'm counseling women, I always say if you're under the age of 35, I kind of have a different methodology than I do with women north of 35, but yet not yet menopausal. And then menopause is when I feel like women and men are most aligned in terms of their hormones are a bit less fluctuating from day to day and therefore, I find often times menopausal women and men have a lot more similarities than they do dissimilarities. And so, when I'm, you know, starting out conversations, I want to know where is a woman still menstruating, where she is in her cycle, what's her sleep quality like because my kind of resounding philosophy is if you're not sleeping through the night, irrespective of gender, it's not the time to be adding in another hormetic stressor. I think quite a bit about nutrition and I think about stress management. And unfortunately, you know, I think so many of us have been conditioned to believe on many levels that when we're talking about often times body composition, wanting to lose weight, desiring to lose weight, we then we have to work out

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really, really hard. And so, as it pertains to women, I really think about all of those key concepts when we talk about fasting to make sure all of those things are dialed in properly so that they don't get a net negative impact on their menstrual cycle or their fertility. Yes, you mentioned sleep, which is obviously a very important factor in health, but when women are perimenopausal, that's a time in their life where sleep can really suffer. Waking up with hot flashes and just really the hormonal changes can really keep women from sleeping well. So, do you find that perimenopausal women really suffer or have a harder time with intermittent fasting because of that? Is that a particularly difficult age group? I think it is a particularly difficult age group because things that used to work are no longer working. Like what served you in your 20s and 30s, suddenly you're completely spun out because you recognize that, you know, the degree of exercise intensity, the amount of stress you're mitigating, really doesn't serve you any any longer. And And for anyone who's not familiar with this perimenopausal period, we know that it's a time when we're not ovulating every month. We're getting waxing and waning progesterone levels from our ovaries. Puts a little bit of stress additional stress on our adrenal glands. And so you're aptly very appropriately mentioning the sleep piece. And so I I will really start there. And it can be as simple as women having to really execute really good sleep hygiene. You know, I think back to when I had infants and toddlers and there was a whole sleep ritual that we

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had to create. And I said we very much have to think the same way. We have to be that proactive so that we are preparing our bodies for bed. And it could be as benign as getting off electronics or wearing blue blockers that mitigate mitigate the blunting of of melatonin secretion our brains. And you know, really just being very mindful about what we're doing preceding bedtime. And so I find for most people Most women when they start making the appropriate changes, even before we think about supplementation or, you know, medication or anything like that, uh many simple changes can really add up. And it could be that, you know, adjusting their macros during the day, you know, the protein and fats and carbohydrates can make a huge difference. I find many people when they start fasting and they start adjusting their macros, their hot flashes go away or they become much less problematic. They have a whole lot more energy. And so the sleep piece is critical. I always say it's foundational to our health. So irrespective what gender you kind of fall into, um I think that if you're not sleeping properly, you want to be really careful about, you know, what your fasting schedule or regimen is like. And you mentioned a couple different age groups. So under 35 and then over 35 but still menstruating and then postmenopausal. Do you have a different um frame of mind in terms of duration of fasting? Cuz I mean I fall into this pattern as much as anybody. You talk about fasting as if it's one thing, but it clearly isn't, right? You can do time-restricted eating whether it's 12, 14, 18, 20 hours. They're all

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time-restricted eating. Or you could talk about two, three, four, five-day fast even. So do you have different time frames that in in this age group you want to focus on this time frame? Another age group you focus on a different time frame specifically for women? Yeah, I mean I think for anyone who's still in their peak fertility years, and I like to think of that as 35 and under. If you're particularly lean, uh I don't think there's a lot of benefit from doing very long fast. In fact, you know, you start to really look at the net impact of prolonged fasting in someone who's very lean, potentially very fit, and very young. And it you know, there's that cost-benefit where I just don't think it's there. So in younger females, I usually will say, you know, 12 hours of digestive rest is great. You know, 12 to 13 hours the week preceding your menstrual cycle is great. That's fantastic. You're still getting benefits. I don't like long prolonged fast. Like I don't want Unless someone is clinically obese, working with someone who's very talented, um is very familiar with with intermittent fasting. And And you're you've got a lot of connection with someone that's knowledgeable about fasting. For the average 35 and under young woman who's still in her peak fertility years, I would say, you know, 14 to 15 hours are probably fine. And certainly not every day, every other day, twice a week. Um I'm not as stringent. Now again, if someone's morbidly obese, working with a clinician that's very knowledgeable, you could certainly try some other strategies if you've got a

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lot of weight to lose. But the lean, thin, um type A, a little bit OCD young women that I I do see on social media, I get a little bit concerned when they want to fast every single day because I look at the menstrual cycle really as a barometer or another vital sign. If your menstrual cycle, you know, maybe one or two cycles get a little bit off, maybe they're a little shorter, a little longer, there's no chance of pregnancy, you've taken a pregnancy test, that's one thing. But when someone's someone becomes amenorrheic, if they lose their period entirely, it's a sign that it's too much stress for the body. So that's that kind of group. I would say perimenopause, 35 to 50, if we're going to just make a blanket statement. Um this is when women really can struggle quite a bit. And so I take it on a case-by - case basis. Um I do like people to aim for that again, that 12 hours of digestive rest, and slowly start moving that fasting window out to see where they're functioning. What I do see in terms of uh you know, people get hooked on they're less hungry, you know, in this age group. This is when as they get closer to 40, whether it's the role of estrogen on, you know, digestive health. But I do see women who aren't as hungry, and so they'll justify one meal a day. And I keep telling them there is no way possible you can get enough macros in in one meal a day in perpetuity. If it's around a holiday, if it's around a celebration, you overate the day before, OMAD is fine. But there's just no way you're going to be able to get, you know,

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enough macros in to sustain your body. And so with women like that, it really is on a case-by - case basis. Focusing on the sleep, the stress management, not over-exercising. And I just find we're a very carbohydrate-focused culture. And when you're looking at statistics that like 88% of the population is metabolically unhealthy, I remind people that we really need to focus on the key satiety macros. Like focus on animal-based protein, you know, adding in some healthy fats if they're not already part of the animal-based protein that you're consuming. And then carbohydrates should be like the last thought. I'm not anti-carb. Um I do think that there's value in women being very targeted about carb cycling or, you know, adjusting their carbohydrate intake based on where they are in the menstrual cycle and how active they are. But So that's that's one bucket. Um again, kind of paying attention to what's going on with the menstrual cycle. And then I always say menopause for many women that are fasting, they just find it's so much easier because there aren't all these, you know, uh hormonal irregularities that they have to kind of mitigate and and worry about. So that's where I think men for the most part and menopausal women really can excel because they aren't worried about the childbearing net impact. For many people, it's a time in their lives where they have maybe less responsibilities. Their children may be out of the house. They may just have you need to focus on themselves and maybe a spouse or significant other. So it might be a time that women are in a position to be able to invest more into their health. Yeah, I think that's a good point, too. What else is going on in your life and how crazy is the rest of your life that it's

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not always a good time to be fasting or changing your routine on a regular basis. So that's a good point. But now you also brought up OMAD and getting enough macros. Whenever I hear that, I think not getting enough protein, especially for women as they age because traditionally um I guess stereotypically women under eat protein anyway, especially if you want to maintain or build lean body mass. So when you talk about fasting, a big concern can be are you getting enough protein? So is that something you see in women that they're they're just under eating protein for the sake of fasting? And how do you weigh, you know, the risks and benefits there? Yeah, it's a great question. I talk a lot about sarcopenia, you know, the muscle wasting with age that is of greatest concern. So I was always encourage people to be aiming for more protein intake. And it could be that they go from 3 oz of fish to 6 oz of fish. It could be that they are having three meals during their feeding window. It might be that they may add in a high-quality protein powder into that mix. But you know, if you look at, you know, muscle protein synthesis research, what it's really talking about is you need to have this leverage of enough sufficient protein intake and then the strength training piece to maintain muscle mass as you're getting older. And I remind people sarcopenia is going to happen unless you do a lot to change it. And I I think the disadvantage that women in perimenopause start to that slippery slope, you know, we build peak bone and muscle mass in our 20s and 30s. And so a lot of people aren't thinking about muscle mass and bone mass until they're in their 40s and

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50s. And maybe they notice it's a whole lot harder to build muscle. It's a whole lot harder to maintain their their bone strength. And especially if they've got genetic susceptibilities to osteopenia and osteoporosis. So from my perspective, it's a huge focus of my work. I remind women that protein is satiating and it's critically important. And I think the the challenge that I have is when we're talking to a woman who wants to change, for example, her body composition. Maybe she's put on some weight in perimenopause or menopause. And they're very carbohydrate-focused or they're plant-based. It can be very challenging to get those protein macros where they need to be. And I kind of align myself with Dr. Gabrielle Lyon who talks a lot about 1 g per pound of ideal body weight. So if someone's aiming to be 140 lb, um that's quite a bit of protein. And And maybe they're only getting 60 at that point. I always say, you know, you're going to stuff yourself if you try to hit 140. So aiming for 10 to 15 more grams each day over a period of time, and then also giving themselves some grace. You know, 100 g is what everyone should be really aiming for at a minimum. But if people can get to 110, 120, great. Don't beat yourself up. But I think for women in particular, if they want to ward off sarcopenia, they want to have muscle uh calorie-building I always think of muscles as a glucose reservoir. And so we know we become more insulin uh resistant as we get older, as we start creeping towards menopause. And I just tell people you can be doing all the right things. And if you are losing

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muscle mass, it is going to be a whole lot harder to maintain a healthy weight and remain as metabolically flexible as you would like to be. Yeah, so if you have a a patient who is not very excited about exercising. They just struggle to do it. They're not consistent with it. And they sort of under eat protein by little bit, not maybe 50-60 g, but say like 70 g or so. If you have a patient like that, would you just take fasting off the table or do you still see a role for intermittent fasting or time restricted eating even in that scenario? I I think intermittent fasting or time restricted eating is good for just about everyone. Even if it's 12 hours of digestive rest. If someone says to me, "I'm really struggling to get my macros in. I'm hungry. I'm going to bed hungry. I'm waking up hungry." I would say, "Okay, let's restructure things. We can always back down." And that's the key thing about about fasting that I think is so critically important for people to understand. It's not about rigidity. It's about flexibility. So, you may flex up and down every day. It might be that someone does uh intermittent fasting every other day. Um if someone really doesn't enjoy exercising, doesn't enjoy longer periods of not eating, I just say then let's eat less often. You know, if we're going to make it as amenable and friendly as possible, like let's eat less often. Maybe you do a 10-hour eating window. You eat three times. You get all your macros in. You're not waking up hungry. And you know, fasting can work at different points in our lives. It is totally okay if someone takes a break. I certainly have after being hospitalized. And I think it's important for people to

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understand that it's not an all or nothing phenomena. Like you may fast for 6 months and then you may have an illness or you might move or it might just be more convenient to do like a a wider feeding window. And that's okay, but it's really about focusing on eating less often, eating for satiety, pushing the protein envelope so that you are contributing to, you know, providing your body with the amino acids it needs to maintain lean healthy muscle. And you know, really thinking strategically. Like I remind people, I think it's almost Mother Nature's way of reminding us that we need less food anyway. Like it's surprising when people restructure the way that they're putting their meals together how much better they feel. They have more mental clarity, more energy, they're sleeping better. And I'm like it's something that's so simple and yet it's so intrinsic to how we are as human beings. And so for many many levels, I think that, you know, when people just kind of become more attuned to what their body what makes their body feel good, it will naturally follow along. But I agree with you. It's all about finding what works best for the patient and being really flexible and encouraging them to be flexible and to give themselves some grace. Yeah, I think that's such an important message because, you know, so many people get lost on social media and you know, the concepts if you're not doing OMAD every day or if you're not doing a 5-day fast, you're you're not really fasting. You're not really getting the benefit. So, you you got to do it that way in order for it to work. But your message is so important that no, sometimes even just 12 hours of not eating or just cutting out snacks or sometimes just the the little differences can make a

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big impact. And I also love your message that is not one way all the time. You can cycle in and out. You can change the duration. And as you alluded to before, someone's menstrual periods may play a role in that as well. So, do you have women do longer fasts like right after their period and then shorter fasts or you know, let me rephrase that. A longer um time restricted eating right after their period and then shorter leading up to their period. Do you usually have them on a protocol that sort of expands and contracts based on that? Yeah, I mean I definitely am of the belief system that the 5 to 7 days preceding their cycle, if they have a 28 or a 30-day cycle, they should not be doing fasting. We also know it's when women are most insulin resistant. So, I may have them tweak their macros. And then once they start bleeding, you know, when when they're most estrogen I don't want to use the term dominant because that gets mistaken, but we know that estrogen dominates as the predominant sex hormone in the first half of the menstrual cycle, that's when they have a lot more energy. That's when they can get away with longer fasts. And then as they get closer to ovulation, they might be doing shorter fasts. And so yes, like teaching those kinds of techniques, I think is really important. Also, women just feel so much better because they're they enjoy the fact that they can flex or they can flux that um that fasting uh window throughout the month and they don't feel so compelled to have to be rigid. Like I had uh actually a clinician texted me the other day and said, "I feel awful. I can barely get to 14 hours fast." I said, "Where are you in your cycle?" And the next text was,

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"Oh, it should my period should start tomorrow." And so even clinicians will do the same thing. They're like pushing and then all of a sudden they're like, "Why am I having so much trouble trying to squeak through the last couple hours?" And I'm like, "Listen, break your fast." Like I certainly do it. I have days when it's like that and I'm like, "Listen, I just can't I don't want to. I choose not to." Um I don't believe in forcing anything. There's very little that needs to be forced as it pertains to, you know, creating, you know, the the circumstances, the schedules that work best for you. And you know, along those same lines when I think about people wanting to do long fasts, I always say, you know, a lot of it's a mindset piece. So, you have to be ready to say, "Okay, I'm not going to consume X during this, you know, 24-48 period 48 hours period of time, but also be methodical and strategic. Don't do it around celebrations when you're going to have people around you eating and celebrating and you're sitting there feeling deprived. It's going to make it a whole lot harder to be compliant. Do it when you're busy. Do it when, you know, you have uh you know, maybe you've got a work project or you're traveling, you know, but pre-COVID, I used to always say that's when I would do a longer fast. If I knew I was going to get on an airplane, change time zones and I'm like, "I don't like the airplane food. I don't like the airport food. It's easy to do this. I'm just going to stay hydrated." So, really figuring out what works and resonates best for you, I think is a really healthy strategy for people to embody. Yeah. Now, switching gears just a little bit here. What about this the the statement

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that when you eat is more important than what you eat? Is that true? Because obviously, you know, what you eat is still important. When you eat is important. Is it truly more important when you eat than what you eat? And would you have somebody work on their eating window first before changing the food, the actual foods they eat? Or how do you see those those two sort of competing variables? Yeah, great question. Well, I would say my kind of prevailing thought process about that is you know, if we follow chronobiology, we would eat earlier in the day and not be eating in the evening, you know, not be eating 3 to 4 hours prior to bedtime. But when I'm working with people and they're new to fasting, we try to clean up the snacking first. So, I always say we're taking baby steps so that we can put you in a position where you can be successful. So, get rid of the snacking and then adjusting macros because we want the satiety to come before, you know, we start doing these these fasting windows because I find if I can get people and it seems like a lot. I mean, as you know, as a clinician, there's a lot of people that are leptin resistant. They're really struggling. They they have the satiety cues they just don't have. So, really working on uh making them feel full, you know, a little more protein, being mindful of your healthy fats cuz they tend to be more nutrient dense. As we start restructuring meals, then they feel empowered. Then they're like, "Okay, I wasn't hungry from dinner to breakfast. So, okay, I got this. And maybe I can go to 13 hours fast and I go to 14." So, my traditional methodology is really meeting people where they are

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first. Um and I always tell patients, you know, tell me the the honest truth because I can help you better if I know where you're struggling the most. Uh so, when it comes back to, you know, when you eat is more important than what you eat, obviously both are important, but I try to get people to close their feeding windows um way earlier than, you know, 7: 00, 8: 00, 9: 00 at night when they're going to sit in bed with a full stomach and they're not going to sleep well. And you know, reminding people we've got melatonin receptors in our gut. I mean, we have all this hormonal regulation and communication within our body. We really want it to be optimized. I I kind of think about how the pandemic has um allowed a lot of people potentially to adjust feeding and fasting windows because they've been home or they've been home more than they might normally be. Maybe they're listening more to their bodies about, "Hey, maybe I actually want to eat dinner a little earlier and I actually sleep better when I do that." So, I encourage people to, you know, really do a little bit of experimentation to find what works best for them. I have some patients who will close down their feeding windows way earlier than they did pre-pandemic because in many ways they've come to realize that they feel better when they're not going to bed with a full stomach. Well, then I guess the last thing we should talk about is I hear you have some exciting news about a book coming out soon. Yes, I'm really really excited. Uh that should be out in March of 2022. It's a book on intermittent fasting in women, really walking women through my personal strategies for not only cycling, but perimenopause and menopause. Very focused on hormone

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supporting hormones and, you know, the unique characteristics that you know, really forces as women to approach fasting a little bit differently than men do. So, I'm really excited for the opportunity. Oh, well, I'm excited to see that. I think that's going to help a lot of women cuz really we do get lost in social media and think of everything as one big lump, but we are individuals and women are not little men. They need to be they need to consider things differently exactly like you said. I think you phrased that very well. So, I think that'll help a lot of people see things from a different perspective. So thank you for putting that message out there and thank you for taking the time. Absolutely. Thank you. It's been my pleasure. Next, let's hear from Dr. Steve Phinney. Now, Dr. Phinney is the chief innovation officer at Virta Health, but his background is a medical degree from Stanford University and has a doctorate in nutritional biochemistry from MIT and completed post-doctoral research at Harvard University. Now, throughout his 40-year career, he's worked as a clinician and as a researcher with over over 87 peer-reviewed papers. Um he's published data from more than 20 clinical protocols involving diet, exercise, oxidative stress, inflammation. He is a professor emeritus at University California, Davis and he's got clinical He's had clinical faculty appointments at MIT, University of Vermont, University of Minnesota, UC Davis, and he's been involved in in industry. I mean, he's he's done it all when it comes to research on nutrition and health. And now, of course, you probably know a lot of the work that they've done out of

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Virta Health, where he is a co-founder and has been instrumental in their work. So, when it comes to fasting though, he's also been pretty vocal about needing to follow the science, what the science says, and what some of the concerns may be. So, as we're going to hear, he's got real concerns about fasting when you're taking medications for diabetes, fasting of different durations, and where to draw the line for risk versus non-risk, a lot about muscle muscle concerns, lean body mass. So, you're going to hear someone who wants to stick to the science and wants scientific proof of efficacy and safety before making broad recommendations. So, let's get into a little bit more of this interview with Dr. Steve Finney. thanks so much for joining us to talk about this really important topic here. So, you know, intermittent fasting has become so popular with some research behind it, but maybe it's it's popularity is sort of outpaced the research. And what we find a lot of times is I'm sure you know, when people start a ketogenic diet, they naturally eat less than they eat fewer times during the day. And you've been vocal about some potential concerns and dangers about intermittent fasting. But, again, in popular media, it sort of all gets lumped together. So, I want to hear from you what you think the best definitions are of time-restricted eating, intermittent fasting, and where you see the border for for where the concern starts. As you're saying, Brent, multiple variations of fasting. Um and it and it's, you know, different

51:29

people have different definitions. I've just mentioned at the outset that Jeff Volek and I posted a did a blog post a couple years ago on our Virta Health blog called to fast or not to fast, where we laid out a what we thought was a our version of of definitions. So, time-restricted feeding typically doesn't um uh restrict calories. It restricts the duration of time people can eat. uh intermittent fasting is typically um uh restricting the number of calories that people eat in a time period. So, alternate day uh time-restricted eating, for instance, would be, you know, eating a limited range of foods every other day. Um uh which might or might not restrict carbohydrates, but typically tries to restrict calories. So, you know, they might say every other day eat you only eat 800 calories. And then in the other on the intermediate days, you eat as much as you want to eat. But, intermittent fasting, some people do like 5: 2, uh which meaning days, so there are 5 days where they eat any as much as they want of any range of foods. And then there are 2 days when they either severely restrict calories or eat nothing you know, have only fluids and electrolytes and and don't eat calories. And then, what I call prolonged fasting is durations of time beyond 2 days of eating um um

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no energy or very very little energy-containing or, you know, foods or beverages. So, when it comes to losing weight, restricting calories is an important thing. You have to take in less than you expend. There's, you know, the science of that may be true, although it's not always the right way to sell it, right? Just to say eat less, move more. We know that doesn't work. So, time-restricted eating and intermittent fasting has sort of been like a hack or a trick to get people to eat less without really, I don't know, you could say struggling and doing it in a way that lowers insulin. But, is there a threshold where you think the risks start to outweigh the benefits for limiting the duration of time in which you're eating? Well, the duration of time for me is not a concern as long as the composition of the intake is pretty consistent. Particularly since at Virta, our primary focus is on people with diabetes. If people are on diabetes medications and they eat a lot of carbs one day because they're told they can eat anything they want, and then on the other day, they have to eat only 800 calories. They they are on this roller coaster ride where, you know, and again, the medications don't wear off 10 minutes after you take them. If you're on long-acting insulin, how do you adjust that? Um uh you know, for the days when you're eating a lot of carbs versus not, and it results in a roller coaster. So, one of my biggest concerns is for people with diabetes, and also to some degree people with hypertension. Um

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Um uh because uh there's a quite quite prompt response to restricting total calories and carbs uh on blood pressure. Uh and, you know, we don't want people on a high dose of medications and being coming you know, being syncable the day when they're restricting. Um so, as long as the composition and calories is consistent from day to day, so that the medications uh are dealing with a consistent dietary response, I'm completely fine with that. Yeah. For uh periods of uh and but you know, for things like uh uh 5: 2, uh 5 days of eating a full range of foods and then 2 days with severe restriction, that to me has uh raises concerns similar to what I just explained. So, raises concerns from a medication standpoint, because it's hard to adjust medication. What about from just an overall health perspective from people who aren't on medications? Well, that's, as you point out, there's a lot been a lot of promoting of these types of diets. There have been a lot of papers published. But, the rigor of the science from much of that is, let's just say not as high as we'd want it to be, but that's true of almost all nutrition studies. People say, "Well, we put them on this diet and we had them report their calories." We all know that reported calorie intake is is fraught in terms of of scientific accuracy. You know, if you

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look at the published literature, there are very few studies that last a year. uh most of them are um you know, not that that closely monitored. So, they have the people come back in for visits um uh to be monitored, but it's, you know, again, it's the tracking in terms of the physiological response isn't isn't always that great. Um uh but there's very little evidence for um time-restricted feeding or for intermittent fasting that it has a significant lasting effect beyond 6 months. And that's true of almost all other dietary interventions that we see classically for patients who are put on a strict diet and are followed out to a year, the maximum weight loss is achieved in the first 3 to 6 months, and then weight regain begins to come back up. And for chronic condition like obesity or type 2 diabetes or hypertension, uh something that where the benefit lasts for 6 months is yeah, it it may be look very good for that 6-month period of time, but for something which you hope the person's going to live, you know, have a better life, you know, for decades, it really doesn't look like it's it's a significant benefit in terms of actual health care. Yeah, I wonder how much of that has to do with compliance though. I mean, cuz you mentioned the DIETFITS study, which I think is the perfect example. You know, in in that trial, they started off for the first 3 months with a true ketogenic diet, but by the

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end of the trial, the quote-unquote ketogenic arm is eating 130 g of carbs per day, and the other arm is eating 210 g of carbs. So, the the compliance of sticking to a ketogenic diet and certainly changed, and that was part of it was designed in the protocol that they could add carbs back. So, I wonder if the same is with the intermittent fasting study, that the compliance just sort of falls off, and so success falls off. Which is why So, the Virta Health trials are are really interesting because it's it's a non-randomized, sort of self-selected. So, in that group, your compliance is going to be better than a randomized trial, period. But, that has shown benefits out to 3 years. So, in those trials, in your experience with Virta Health, do most people just naturally adopt a type of time-restricted eating? And then, the second part of that question is, do you think that helps? Do you think that's beneficial? Well, uh excellent question. Um one of my favorite slides that I use in my talks is one that I put put up and leave up for 4 or 5 minutes. And it shows, you know, our a kind of a general depiction of four phases of adaptation to a very low-carbohydrate or ketogenic diet. And that is, when you first start it, you're right, people undereat calories significantly. So, somebody who's who's you know, if you put them in a metabolic chamber, you know, you you define them you know, with a a resting energy expenditure of 2, 000 calories per day, and if they were able to walk around outside of a chamber in activities of daily living, they'd be burning 2, 500, but they eat 1, 500

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burning 2, 500, but they eat 1, 500 calories a day. So, they spontaneously voluntarily um uh able to reduce their caloric intake to 1, 000 calories below need. But, when we track them for 3 months, 6 months, 9 months, 3 months, they're still losing weight, but the rate is slowing down. At 6 months, they've started to plateau. By by uh 12 months, they're they're flat, and hopefully at 1 year, but their energy intake goes up. We tell them keep their your carbs under maximum 50 to 60 grams of carbs and for people who are more insulin resistant they can for instance with type 2 diabetes many of them have to to stay under 50 grams of carbs per day. We hold the protein is always moderate typically about 15% of daily energy expenditure not intake cuz the macros are of no meaning if you're under eating calories by a thousand you know everything looks magnified. So they increase their fat intake and they and we don't say today eat 10 more grams of fat we just say eat fat to satiety and that's a constant message over a year or longer. What we find is that they for people who are successful they have increased their total amount of fat. And when they get to weight stability their energy intake equals energy expenditure. The ketogenic diet doesn't always you know if you're in ketosis some people say oh if you're in ketosis you got to be losing weight. The answer is gosh I wish that worked for me cuz I've been on a 14 and a half year

1: 00: 33

plateau darn it. Because my intake equals my expenditure. Anyway long answer is that over time people's um uh spontaneously as they lose weight um they come to a new you know I just people used to talk about the set set point you know you have your your set point is you know you're going to diet lose weight and you gain weight back up to your previous set point. Well people lose weight and they come to a new weight stability point. Um I you know it was a very clever person I think it was Albert Stunkard who was head of psychiatry at University of Pennsylvania. Albert known as Mickey to his friends. Um who was a remarkable scientist he called it a settling point. That your new you know it's not set point it's settling point. You can change your settling point by changing the the composition of your diet and being in nutritional ketosis for most people results in a significantly lower settling point. Um where they're in a new stable state but at a lower body mass. But let me stop there cuz I can wander on a lot about the fit how that might work physiologically. Okay. Well so let let's get back to the intermittent fasting and time restricted eating concerns though. I mean you've been very vocal um both on on the blog at Virta and in talks that you've given about the risk of muscle loss with intermittent fasting.

1: 02: 03

And there have been some recent studies actually looking some looking at alternate day fasting and some looking at time restricted eating that have shown loss of lean body mass. Now when we lose weight especially for people who are obese it it's normal to lose fat mass and lean body mass at least in the beginning but you want to maximize your fat mass loss and minimize your lean body mass loss. So specifically when it comes to intermittent fasting when do you have concern that you're losing too much lean body mass and that you would recommend against the fasting? Okay. If people are eat if the intermittent fasting is um again is that if we're talking about every other day fasting is it a total fast or is it a severely reduced caloric intake? Um if it's 5: 2 again is it total fasting for two days or is there the opportunity for protein intake? Because the prime two determinants of of muscle loss are total calories in and protein. Um with the exception which my first um um study in a eu-caloric feeding study where we fed people stable you know their their calories and maintained their weight. Um we demonstrated that when people go in nutritional ketosis they lose lean tissue for the first week of adaptation. And then their body if the protein is adequate and for I what we've defined we meaning my mentors

1: 03: 33

before me and my collaboration with Jeff Volek is 1. 5 grams of kilog per kilogram of reference weight that means not your true body weight but the old quote you know um healthy weight Metropolitan Life Insurance Company healthy weight. Not that that's ideal but it's a a reference point for protein intake. If you get 1. 5 grams per kilo um in the context of a ketogenic diet um once you're keto-adapted that's plenty and people can actually gain lean body mass. I won't name the name of a very popular uh author of books around lifestyle uh decided to um who was a friend of my CEO went on a uh on a ketogenic diet he figured he'd do it for three months he actually did it for a year. And this guy is a very aggressive um participant in the gym. And he said and he he kind of he was he's quite buff when I met him a few years ago and he kind of not quite put me up against the wall and said you have to explain to me how eating a ketogenic diet I could gain 7 lb of lean body mass in a year. So consistently being in nutritional ketosis with that amount of protein can can preserve and people can build lean body mass. Right. My concern is when you go in and out let's say you have two days of of a week when you're in ketosis and five days when you're not. Who's studied that in terms of you know how does the body deal with that roller coaster? So it's not just in terms of controlling blood glucose if you're you

1: 05

know diabetic it's also the hormonal milieu that the body needs to optimally maintain um uh muscle mass but other things you know skin um uh gut integrity and things like that need to be studied before we advocate it and that's not been adequately studied. So if if someone is following a ketogenic diet or not following a ketogenic diet but getting their adequate protein and doing some sort of resistance training and wants to eat one meal a day a couple days a week because they find it helps them curb their cravings and curb their appetite and and help them kick-start their weight loss do you have concerns that they're losing muscle during that day and need to do something else or the one meal a day every now and then you're okay with? I'm trying to sort of see where your where you draw the line in the sand where you say okay now you have to be concerned about muscle loss and now you don't have to be as concerned about muscle loss or is it not that clear? Maybe I can't get you to draw a line in the sand. Now I don't want to be grumpy old man although I am but it's you know troubling the data. I know people who've done that and do well. But doesn't mean everybody has that capability of doing that. The other thing we need to be careful is we we should not presume that overweight people have extra lean body mass to lose because we know that many people with type 2 diabetes particularly if it's been long-standing for like you know

1: 06: 36

since five or more years since diagnosis actually develops a degree of sarcopenia. You know reduced lean body mass. And one of the things that we see in our diabetes population is when we get them on a well-formulated ketogenic diet people report you know it really bothers me I get on the scale I've been doing this really faithfully my ketones are in the you know the desired range and I've only lost you know 6 kg and other people I know for the same period of time have lost 10 or 20 10 or 15 kg. Mhm. But then they say but the interesting thing is my clothing size has gotten a lot smaller. Because they've you know lost adipose tissue but gained lean body mass. And I had one when I was back when I was in my earlier years when I had access to meta to do metabolic ward studies I did a study in 12 overweight women uh who were put on an 800 calorie a day very low calorie ketogenic diet. And we had them um we were did uh um uh underwater weighing and was also did collected uh 24-hour urines from them every day. They were it's an inpatient metabolic ward study for six weeks. And um the the most accurate way to determine if someone's gaining or losing muscle is by measuring how much protein breakdown product is coming out in the urine and in the feces and we collected both and measured total nitrogen not urea. So we did a very rigorous study of nitrogen out and they were all getting

1: 08: 06

precisely the same amount of protein coming in adjusted for their stature. So 1. 5 grams per kilo. And what we found is that on average uh they maintained lean body mass over that six week period of time. Half of them did a progressive endurance exercise not resistance exercise over five of the last six weeks. And that didn't affect again that's cardio not resistance but it didn't affect the retention of lean tissue. But the fascinating thing we found Brett is that the weight range weight loss range um now they they all they only want to know what their weight were in pounds they didn't want no kilos but uh I think you know we the average weight loss in six weeks was uh 14 lb. Which is you know pretty good particularly if you're maintaining lean body mass. Yeah. But it ranged from 7 to 20 lb for these individuals all of whom were middle-aged um you know premenopausal women. The fascinating thing is the there were three women who lost less than 10 lb. So that put them you know significantly below the 14 lb average and all three of those showed very prominent lean tissue gain. These are middle middle-aged non-diseased women who came in with moderate sarcopenia and on the ketogenic diet with or without exercise gained

1: 09: 36

lean body mass. Uh so, you know, we people we don't always respond identically to the same intake. So, again, when you have an individual who gets up in front of the room and said, "My personal story is I did this and look how great it's been for me." My response, I don't shout it out, but my response is that's great as long as you only give that advice to your identical twin or however many clones you happen to have generated uh because it is clearly genetic how you you respond to any particular intervention is is to a great extent genetically determined. So, would it be fair to say then that maybe your concern is less about um the evidence showing it's harmful compared to the lack of evidence showing it's safe over the long term? Sure. For intermittent fasting? Particularly across a broad range of individuals. Mhm. So, again, we would see a very different I mean, I was surprised that we had non-diseased healthy moderately overweight women in that group of 12 and they had a very diverse response to the you know, to the exact same regimen. Um but if you're dealing with a couple hundred people and some of them are older have you know, varying health backgrounds and medical conditions and medications, having a kind of a blanket response of oh, do this cuz it seems to work for me or for this small group of people or for this group of case reports that I've

1: 11: 06

published. And again, a lot of what's published by the advocates are case reports. Sure. And you point out that our our uh our Indiana University Health Study with Dr. Hallberg that we did through Virta that was not a randomized controlled trial, but it was a parallel parallel arm controlled trial. And um and uh we did that in in almost 400 our intervention with ketogenic diet was in almost 400 people um the majority with type 2 diabetes and some with prediabetes. And you know, we report significant um adverse events. Uh and luckily, we found no major adverse events and no major problems with the diet tolerance of the diet itself. Which is in 400 people, that's pretty tolerable. Uh pretty you know, pretty remarkable. Yeah. But I and again, I don't want to say, well, if you can't do something like that, you shouldn't be talking about it, but one has to be very cautious of small groups or anecdotes or case series being used to promulgate a a broader uh spectrum dietary form of dietary advice. And then, I just want to point out the place where I have my biggest concerns in terms of metabolic impairment and loss of lean body mass is with prolonged fasting. Um and you know, we don't need modern studies to um kind of repeat what was done elegantly

1: 12: 37

and very accurately back in the 1960s and 1970s. So, George Cahill at at the Joslin in Boston and Aaron Stornick at uh Wadsworth VA in in the LA in Los Angeles uh did studies of total fasting in patients um where they very accurately measured um changes in in uh lean body mass by measuring nitrogen excretion. Uh the same technique we used in that group of women in which I also used in my prior my bike racer study. Um and what they demonstrate is that with total fasting in the first day or two, there is very little loss of lean tissue. But by day three the body realizes that that realizes metabolically the body responds to caloric deprivation by using um uh amino acids from from protein uh to produce um glucose because the brain before before you're keto-adapted, the brain has to be fed by glucose cuz it can't burn fat per se. Uh and so, with total fasting by within the fourth or fifth day of a total fast, healthy normal people and and even and and healthy obese people very uniformly will lose about a pound of lean tissue lean body mass probably much of which is from muscle, but it comes from gut mucosa, liver, kidneys, places where there's high

1: 14: 10

turnover in the protein pool. And that persists for about 2 weeks. By the end of 3 weeks, you're down to half a pound of lean body mass and then at 4 weeks on average and you guys say on average cuz we had people's responses vary. People were down to a quarter pound of lean body mass and then for studies which you know, they had some people on a total fast for 60 days and out to 60 days, they were still losing a quarter pound of lean tissue. Yeah. If you do it less rigorously, if you only measure the urea in the urine, not total protein breakdown products because when you're fasting, quite a bit of the quote nitrogen from protein comes out not as urea nitrogen, but as ammonia. And so, if you have 2 g of ammonia, 1 g of creatinine, and 1 g of urea, you've got 4 g of of protein or nitrogen coming out. Each gram of nitrogen in urine represents 1 oz of lean tissue. So, that's 4 oz of lean tissue lost, but if you just measure urea, you only see 1 g. You say, "Oh, they're not losing much muscle at all." And there are people who've been made that mistake and don't want to be corrected when I pointed it out. You know, I'm not trying to be a grinch. I'm not being a grumpy old man. I want to be scientifically accurate because losing a quarter pound of lean tissue a day isn't particularly if someone's starting out with even a mild degree of sarcopenia, is not a good thing. And and then there's the effect of total fasting on resting metabolism. Right. it's it's been pointed out that in the first day or two of a total fast, your resting energy expenditure

1: 15: 41

goes up. Mhm. And that's well known. Right. from the' 60s,' 70s, and' 80s all pointed that out. But it only lasts for the first 2 days and that's the adrenaline response or catecholamine response to caloric restriction. Right. So, in the beginning, growth hormone goes up, resting metabolic rate goes up, protein excretion does not go up yet, but then you reach this threshold where everything seems to sort of turn back down where growth hormone comes back down, resting metabolic rate comes back down, and that's about the same time that protein excretion seems to go up. So, does that seem to be the the cutoff point that most people need to be most concerned with when doing caloric restriction? In terms of lean body mass loss, cumulative lean body mass loss, and reduction in resting metabolism when it's done once we know that it's it's probably harmless. But what if you do it the uh you know, 5: 2 for 3 months or 6 months? Who's published those data? Yeah. I'm not saying that it that's harmful. I'm just saying no one's proven that it's safe and it's safe across a broad range of phenotypes. People ranging gender and and age and underlying disease situations. So, again, I but um I mean, we know a very popular blogger and writer um uh in the low-carb space who did uh apparently two periods of total

1: 17: 13

fasting for lasting 25 to 30 days um uh it did not appear to benefit that person's health long term. Mhm. Uh and we also know from that very um I I would say sadistic TV program called The Biggest Loser where people were competing competing with each others for six streams of caloric restriction and exercise that when you know, Kevin Hall and his team brought a people those a group of those people in and studied them was it 6 years after? Yeah. That many of them had lost they kept some weight off. Many of them had regained their weight, but as a group, they had had a deficit of resting energy expenditure of 400 calories a day. Even those who had gained their weight still had their resting metabolic rate reduced. Yeah, hadn't recovered 6 years later. Yeah. That does sound dangerous. And and again, that's I mean, I have differences with Dr. Hall on a number of things he's done and the way he's interpreted data, but I think that's a very useful block of data uh to help us say, "This is worrisome." And if before we advocate it, it should be carefully studied. Yeah. And to say that you know, if we take religious practices as an as a reason to do it I think it should be reserved for religious purposes until it's proven that it's of benefit to health. You're you've shown how you are the consummate scientist and you you

1: 18: 43

defer back to the science and you want to see what the research shows. But you're also clinician. You've also taken care of patients. So, if you had a patient who wanted to fast, who sees some success in fasting 1 day, 2 days would you be able to make some recommendations to that person to say, "Look, I've got some concerns, but these are some of the things you can do to maybe mitigate the concerns of losing lean body mass if you want to fast for a day or two even though the science doesn't show long term as beneficial, here are some of my clinical guidance to mitigate some of the risks." If I said yeah, I don't give advice to patients lightly. They sometimes find that you know, talking to me for half an hour gets a little bit boring or whatever. But, what I will tell them over in part of as part of a discussion is, "Listen to your body. How do you feel? Is Are you Is your strength better? Is the same? Is it worse? You know, if you used to be able to open a pickle jar just to pop off easily, but it did Now, you have to struggle to get it off or you get one of those, you know, clamp devices to you know, we you need to worry about that. And yeah, actually grip strength is a very simple measure of of muscle function. And yeah, there have been studies done where, you know, grip strength followed over time is a very good predictor of of increased mortality people under a certain level. So, just just a sense of

1: 20: 14

of of grip strength um uh can tell somebody if if they're getting into trouble um uh through doing something, you know, repeatedly over many months. Again, something done for 1 month, as long as it's not total fasting, as long as you're getting enough protein in most days where, you know, that that 1. 5 g per kilo represents 75 g typically for your average 75 80 g for your average female and a 100 g per day for your average male uh from quality protein sources, um they're not going to get in trouble. But, um the other problem I have with intermittent fasting is for some patients behaviorally, it's a slippery slope. Ah. They do it for 5: 2 and it, you know, for the for for 3 or 4 weeks, you know, they they seem to start losing weight and then their weight starts plateau and they get frustrated, so they start doing 4: 3 and then 3: 4 and it becomes a slippery slope to try to maintain a you know, uh two or you know, somebody wants to lose 30 lb. Uh I don't see anything credible published in the literature about intermittent fasting or time restricted feeding that gets anywhere near that degree of weight loss for the average person that the average weight loss is typically are are less than 5% of initial body weight, which translates to anywhere from 10 to 15 lb for overweight people. Well, and you also brought up the Biggest Loser study, so you have to wonder at some point, does even

1: 21: 44

short-term fasting multiplied many times, at some point does it mimic that chronic caloric restriction that will then reduce resting metabolic rate and make maintaining weight loss even harder. But, like you said, I guess we we don't have that data. We don't know where that threshold is. No, we don't. So, I I try to be evidence-based in what I do with patients. And um I say jokingly when I went to medical school, they spent, you know, 4 years teaching me when I'm talking to patients always reassure the patients that you know what they need. So, I say in medical school, they taught me to say, "I know." And then, perversely, I went back after I finished my medical training, I went back to graduate school because I had this absurd infatuation with nutritional biochemistry and they spent the next 3 and 1 / 2 years teaching me to say, "I don't know." Right. Because as And the the famous biochemist Arthur Kornberg, who was a the the head of biochemistry at Stanford and a Nobel laureate uh told us in the first day of our biochemistry course, he said, "We're going to teach you what we think doctors need to know about biochemistry, but I need to warn you that we've been doing this for 30 years. And in our experience, about every 10 years, when we look back at the curriculum from 10 years previously, we've discarded probably a quarter of what we were teaching because it turned out not to be true. Right. So, we have to assume that what we're teaching you now is half right and half wrong. We just don't know which half is which." And what he was telling us is, you know, be very careful about today's truth, today's dogma, because you know,

1: 23: 15

science is a moving target. And we have to be very mindful that that some of the what things we we strongly believe to be true right now uh aren't true and will need to be discarded. And so, one has to have a degree of humility around uh what what we were taught. Uh if if we want to uh be the best advisors for our patients. Uh that is great advice right there. I appreciate that message very much. Well, some really good points brought up there by Dr. Finney. The medication one being a big one. The roller coaster of what's going on with your blood sugars if you're eating, if you're not eating, trying to regulate medications. That's a real concern. For those not on medications, though, the concerns about lean body mass and how you feel and and what happens long-term, those are real concerns, which leaves us in a little bit of a limbo, right? Where we know anec - anecdotal reports of people doing very well, where there's shorter-term studies of people having significant benefit. But, some showing lean body mass loss, some not showing lean body mass loss. So, again, the keys go down to protein, um some resistance training, and then duration and how frequent the fast is. Where's the sweet spot? We don't know. So, according to Dr. Finney, we need more evidence to show that. Now, according to some of the other our other experts we interview, though, uh you can sort of play around with it and and measure do your own n of 1 experiments, which takes time, which takes effort. But, you really need some sort of objective measurement to prove safety and efficacy, and that makes sense, right? Rather than just sort of shooting in the dark, you want some evidence um of benefit. So, uh we'll

1: 24: 45

hear more about that. But, that I think that those were some very good points brought up by Dr. Finney. Well, that's a wrap. That's the second part of our two-part series on time restricted eating and intermittent fasting. Hopefully, you came away with this two-part series with a better understanding of the science about the circadian rhythm, about time restricted eating, about the potential benefits and why those benefits may happen and got some real good clinical tips about how to succeed with time restricted eating and intermittent fasting and some precautions and things to be um to be cautious of when embarking on this. So, I guess one of the keys to just reinforce is time restricted eating intermittent fasting has to fit with a nutritional profile that's giving you adequate nutrition, where you're getting enough protein, where you're getting enough nutrients, macro and micro nutrients. And uh where you're not putting yourself into a chronic caloric deficit that's going to lower your metabolic rate and have some potentially negative uh outcomes. So, um if you also if you have chronic medical conditions that you're trying to treat with time restricted eating, please make sure you're working with a a clinician experienced with it. And if you need to find somebody, we've got over 600 clinicians listed on our website uh find your doctor website at dietdoctor. com. Which also leads me to the last point that we have our diet doctor pro membership, which is specifically for clinicians. So, whether you're a doctor, uh nurse, a health coach, a dietitian, uh personal trainer, anybody who's involved with trying to make people healthier, we want to work with you and we want to support you with our diet doctor pro membership. So take a look at our diet doctor website on the

1: 26: 16

information about diet doctor pro or if you're interested and want more information, please reach out to me, Brett at dietdoctor. com. Um I'm happy to uh talk to you more about it because I think this is something where we can really help a lot of people get healthier and help a lot of clinicians succeed with their clients. And that's what we're here. We're here to help. So, thanks for joining us on the diet doctor podcast.