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Is Intermittent Fasting Good For You?


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You can’t answer this question with a yes or no. There’s no one-size-fits-all approach, and intermittent fasting could be a good idea or it could be a terrible idea, depending on your circumstances.

Revolution Health Radio podcast, Chris Kresser

When you look at the research on intermittent fasting, I would say it’s mixed. There’s definitely some research that suggests that it is beneficial for weight loss and also, more particularly, the improvement of metabolic markers, blood sugar, lipids, and things like that. But I think the confusion arises for the same reason that it arises on a number of different subjects — individual circumstances vary. And those circumstances might change over a given period of time.

In this episode, we cover:

5:15  Situations where intermittent fasting is a good idea
9:10  Who should be cautious about intermittent fasting
10:32  When should you fast?
15:00  Fasting recommendations

Steve Wright: Good morning, good evening, and good afternoon. You are listening to the Revolution Health Radio Show. I’m your host, Steve Wright, co-author at SCDlifestyle.com. This episode of RHR is brought to you by 14Four.me. Now, if you haven’t heard of this program yet, it’s a program that Chris put together that’s designed to reset your lifestyle over a 14-day period. It’s going to do that through the foundational steps that we are usually talking about on the podcast, things like diet, sleep, movement, and stress. If you’ve ever tried to implement healthy habits in your life, you know that it can be very hard to integrate them into daily life and stick with them when things come up, and so what Chris has done is he’s created this program to really walk you through step by step using the best knowledge that we have today from science and habit formation on how you can really implement these throughout your life and do it sort of in one big reset. So if you haven’t yet, check out 14Four.me. That’s 14Four.me.

All right, on with the podcast. With me is integrative medical practitioner, healthy skeptic, and New York Times bestselling author, Chris Kresser. Chris, how is your day going?

Chris Kresser: It’s good. Lots of fun stuff going on. Busy as usual, but also just enjoying the beginnings of summer here and spending more time outside. How about you?

Steve Wright: Yeah, I’m having a delicious day.

Chris Kresser: That’s unexpected! I like it, though. I like it.

Steve Wright: Yeah. I’m trying to be done with the good, great, cool type of things. I’m trying to come up some different words.

Chris Kresser: Well, I will expect a new adjective from you on every podcast. That’s your homework.

Steve Wright: Oh, boy. I’m going to have to think about this.

Chris Kresser: Break out the dictionary or thesaurus.

Yeah, we have a really great question today about intermittent fasting, so let’s give it a listen.

Question from Codi: Hi, Chris. You often talk about your own practice of intermittent fasting on the show, and I’ve been doing some reading about it. There’s some debate about the utility of intermittent fasting for females due to special hormone and reproductive considerations. My own personal situation: My hormones have always been a little bit out of whack, and I have very low adrenal functioning and low hormone production across the board. But I’ve been reading about intermittent fasting as a way to improve my insulin sensitivity and potentially also drop that last 5 to 10 pounds that I’ve been trying to lose. So I’m wondering if you could talk a little bit about intermittent fasting on your show and if you could share some recommendations for how often someone should intermittent fast, say, once a week, twice a week, and if you recommend that they pair that with caloric restriction or simply restrict the window of time that someone eats during the day. And lastly, I’m wondering if there are any special considerations that you have for women or for other health conditions in general. Thanks so much for your time. I look forward to your answer.

Chris Kresser: All right. Well, thank you, Codi. This is, of course, something that’s of interest to a number of people. We get this question a lot either through the podcast or on the blog, from my patients, and it is something that I think there’s a bit of confusion about.

When you look at the research on intermittent fasting, I would say it’s mixed. There’s definitely some research that suggests that it is beneficial for weight loss and also, more particularly, the improvement of metabolic markers, blood sugar, lipids, and things like that. But I think the confusion arises for the same reason that it arises on a number of different subjects. If we try to ask the question, is intermittent fasting a good idea? and just answer it with a yes or no, that’s never going to work because as I always say — at the risk of beating a dead horse — there’s no one-size-fits-all approach, and intermittent fasting could be a good idea or it could be a terrible idea, depending on your circumstances. And those circumstances might change over a given period of time for a given person, so it’s not even accurate to say intermittent fasting is a good idea for this person but not for that person, because those circumstances that determine whether it’s a good idea can change over time.

Steve Wright: I can echo that because I’ve played with this extensively, and I have noticed that over the last six years.

Chris Kresser: Yeah, so I’ll be curious to hear about your experience.

Situations Where Intermittent Fasting Is a Good Idea

Let’s talk a little bit about some of the scenarios and situations where it is a good idea. It’s something that I would think about with patients when rapid weight loss is desirable, when their blood sugar is elevated and there’s some insulin and leptin resistance, maybe dyslipidemia, if they have those circumstances and overall otherwise they are in relatively good health, so they’re not dealing with a really serious chronic infection, they’re not dealing with a chronic fatigue type of problem, their adrenals or HPA axis — you know if you’ve been listening to this for a while I use the adrenal term tongue-in-cheek — but their whole system that governs stress tolerance and stress management is in relatively decent shape, they’re sleeping pretty well. If they meet all those requirements, then I’m certainly happy to entertain intermittent fasting as a strategy for improving their health, helping with weight loss and helping improve blood sugar and lipid markers.

I said something about chronic infection being a contraindication for intermittent fasting. Paul Jaminet and some other folks have written about intermittent fasting as a way of dealing with chronic infection because it upregulates a process called autophagy that may be helpful in dealing with chronic infections. In my own practical experience, I’ve seen kind of mixed results with intermittent fasting for chronic infection. If somebody’s just really exhausted and their HPA axis is really shot — which it often is with chronic infection — intermittent fasting can often, in my experience, take people in the wrong direction who are dealing with those symptoms. But in some cases, I have seen an improvement, and it may be in part from just giving the digestive system a rest and that leaves more energy for fighting the infection, or it may be because of the upregulation of autophagy.

Steve Wright: I have an interesting nugget on that from my personal life. I started playing around with intermittent fasting back in, like, ‘09 when I started my entire health journey, before I even had switched my diet over, and I have done all the different methods out there. You name the person, I’ve tried it. And about a couple years into it — I would always do it for a while and then quit and do it for a while and quit — I started doing 24-hour fasts and sometimes dinner-to-dinner-type fasts, and every once in a while I’d start getting these awful pains in my stomach about 8 to 14 hours into the fast. So I contacted some of the experts who write about intermittent fasting, like, hey, have you ever heard of this? No one had any ideas, had never heard of this, didn’t know what was happening. Fast forward to, I don’t know, about a month ago, and I’m talking with Dr. Steven Sandberg-Lewis. He’s a gastroenterology teacher up in a Portland naturopathic clinic, and he was helping me out with some research on heartburn, and he was saying that it’s very common for people with H. pylori and inflammation of the stomach to get pains if they fast in their stomach.

Chris Kresser: Yeah.

Steve Wright: And it turned out I had H. pylori back then and I had treated it since, and so that’s just to go along with the infection things.

Chris Kresser: Absolutely, yeah. It’s kind of a sidenote. I don’t want to go too far down that road, but it is a big red flag. If you have pain on an empty stomach, that’s a big red flag for H. pylori and other possible gut infections, for sure. That’s a very interesting tidbit there.

Who Should Be Cautious about Intermittent Fasting

So yeah, those are the typical circumstances when we would think about intermittent fasting. Now, on the other side of the coin, the circumstances in which I would be cautious to recommend intermittent fasting include some of the things that Codi mentioned in the question, which is if there is hormone imbalance, if a woman is trying to maximize fertility, unless that woman is really overweight and has blood sugar issues, in which case intermittent fasting may actually move the needle in the positive direction. But if that’s not the case, if weight and insulin and leptin resistance aren’t standing in the way and the woman is just generally trying to maximize fertility, I probably wouldn’t recommend it. If someone has pretty significant HPA axis dysregulation or adrenal fatigue — so that would manifest as feeling tired when you wake up in the morning even if you get enough sleep, having afternoon energy crashes, not being able to fall asleep or stay asleep, your quality of sleep is poor, you have poor stress tolerance, poor exercise recovery or exercise tolerance, these kind of classic signs of — I’m doing air quotes here — adrenal fatigue, in my experience, intermittent fasting usually makes those patients worse.

When Should You Fast?

Now, so far we’ve been talking about intermittent fasting as if you’re doing it every day or you’re not doing it on any days, and of course, it doesn’t have to be like that. As I have often discussed and you know if you’ve been listening to the show for a while, sometimes when Steve asks me what I’ve had for breakfast, the answer is coffee and cream, which is intermittent fasting. Sometimes the answer is a relatively large breakfast. So I’ve mentioned this before, but the way I approach intermittent fasting is I do it when I feel like it or I do it when my life circumstances call for it, like my morning just got away from me and I have a lot going on and it just feels like to rush eating a breakfast, inhaling my food in between commitments, just doesn’t make sense and I would rather just fast and be a little bit more deliberate with my morning. But I have gotten to the point — and I’m curious where you’re at, Steve — where I can just kind of check in with my body and, based on how I’m feeling, determine whether eating makes more sense or not eating makes more sense. The kind of triggers that I look for would be if I had a good night of sleep, if I’m feeling rested, I’m feeling strong overall — all of the cylinders are firing, so to speak — then that’s a good morning for me to fast if I feel like it. If I have had a crappy night of sleep or I’m feeling just unusually tired or run down for any reason, then I’m probably not going to do that because I think I’ll usually feel worse in that situation.

So I think eventually after you experiment a bit and go periods of time where you’re intermittent fasting, periods of time where you’re not, you’ll get a sense of how it makes you feel, and then you’ll be able to make that determination yourself.

Steve Wright: Yeah, I think what you just mentioned is really important. If you’re looking at your life and you’re consistently not getting quality sleep due to life circumstances, like a newborn baby or something like that, or a big project at work, or if your stress is extra high because you’re moving, those are probably not the best times to be intermittent fasting. Whenever I’ve actually attempted intermittent fasting those times, that’s when it’s like agonizing and it doesn’t add value to my life. It seems like more of the times when I’m kind of in flow and, like you said, I just look in the refrigerator and I’m like, I didn’t go to the store and I should’ve. OK, well, I’ll just fast until dinner or something like that. That seems to be how I do it these days.

Chris Kresser: Yeah. That’s sort of like lifestyle-based intermittent fasting, which is fine. I mean, in a way, that mimics the ancestral pattern, right? Like, oops, we didn’t have a successful hunt, so we’re going to be fasting now.

Steve Wright: Yeah. I think the other time that I try to use it — this comes from Brad Pilon; he’s one of the fasting people out there who has a pretty good book — is around events when I know I’m going to overeat. I’ll do it the day after Thanksgiving or something like that. Or if I’m just know I’m going to be eating out a lot, eating a ton of “paleo treats” or whatever, I might fast the day before that weekend or that trip or something like that.

Chris Kresser: Yeah.

Steve Wright: Just to kind of store up some calories.

Chris Kresser: Yeah, that’s a good idea. That’s another circumstance.

Sometimes I’ll do it when I’m flying. We’ve talked about this before. I’ll often bring my own food on a plane, but in some cases I’ll just fast completely from my house to wherever I end up and use that as an opportunity and just focus on other things while I’m traveling.

If I feel like I’m coming down with a cold or some kind of viral thing, I often find that fasting is helpful, or at least just eating more sparingly, so that’s another situation where it might be helpful.

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Fasting Recommendations

In terms of Codi’s question, there are a couple of other kind of subquestions there. One was if it’s recommended to pair intermittent fasting with caloric restriction or simply restrict the window of time that somebody eats during the day. I’d say my recommendation is not to actually count calories for most people when they’re intermittent fasting and just restrict the window of time that you’re eating. So you might eat all of your meals between 12 and 7 p.m. and then not eat anything outside of that. And different people will have different experiences. If you’re trying to lose weight, typically a lot of people will still lose weight even if they’re not purposely restricting calories. If they’re just compressing their food intake into that window, they may still lose weight because there’s an involuntary calorie restriction that happens and they get improvement in insulin sensitivity and leptin sensitivity. Maybe the types of food that they’re eating will change and how they’re metabolizing that food will change. So in most cases, I just recommend that people focus on restricting the window of time that you eat.

If you are doing daily intermittent fasting in a compressed food intake window, like 12 to 7 p.m., and it’s going really well for you and you’re really liking it and you’re getting a lot out of it, one way that you can kind of up the ante is do a biweekly, monthly, or even weekly 36-hour fast, where from 7 p.m. until noon the following day — so let’s say 7 p.m. on Thursday you stop eating. Then you don’t eat again until 12 p.m. on Saturday. That’s another way of fasting intermittently, and in that circumstance, you would definitely be decreasing your overall calorie intake in a given week by skipping that day of food intake.

So there are a lot of different ways to do it, and ultimately it really just comes down to what makes the most sense for you given your health status, your goals, and then your circumstances and lifestyle.

Steve Wright: Yeah, I definitely used to do, like, two or three 24-hour fasts per week, and I think they’re good. I think where intermittent fasting becomes a potential downside if you’re doing it on a month-by-month-by-month basis, other than all the other health stuff you talked about, is if you stop being social because, for instance, everybody’s going to go to a dinner party but today was your fast day and you don’t want to be in that environment and be smelling that kind of stuff. I think that’s one thing I became aware of, too. Like, oh, I think fasting is kind of affecting my social pattern, and I’m not cool with that.

Chris Kresser: Yeah. I mean, that’s fine for short periods of time, too, if you have a particular goal, but that’s a really good example that you bring up, because we’re always having to balance these different choices that we’re making. When we make one choice, that choice tends to have repercussions in other areas of our life, and if you maximize one area of your health and you put all your energy into that — let’s say your nutrition and your diet — then it’s very likely you’re going to go out of balance in other areas of your life. I tried to address this in my book by talking about the importance of pleasure and social connection and fun and having a sense of purpose in your life because I really believe that having this kind of balance is arguably more important than optimizing the last 5% to 10% to 15% of any one particular category. And if you look around at some of the healthiest and most successful people, you’ll see that that’s true for most of them. They have a rich life. That’s what this is all about ultimately, is creating a life that we love living and having a sense of meaning and purpose and rich social connections and fun and that we enjoy our life and we love being here on this planet. Optimizing our nutrition is a big part of that, but it can be easy to get a little carried away there, as we all know.

Steve Wright: Yeah. And I do want to just say that many listeners might not know, but some might know that I used to be 60 pounds heavier than what I am now, and part of how I lost a decent chunk of weight was through changing my diet and then incorporating the intermittent fasting two to three days a week into my life. That, back then, was obviously a really important goal to me, and I think I like the fact that intermittent fasting plays so well into a real food diet. You know, you’re not, like, eating some of the crazy body building diets or any sort of “calorie counting.” You’re just saying, hey, I’m not going to eat from noon to noon or 7 p.m. to 7 p.m. or something like that.

Chris Kresser: That’s right. It’s really not making any changes on those levels. You’re not restricting calories. You’re not counting them. Like you said, you’re just doing what you’re already doing, but you’re doing it less frequently or at particular times during the day.

The other thing we haven’t even talked about, or I guess I alluded to it when I was saying that I will often do it in the morning when I’m busy and doing other things, but I sometimes get tired of eating and preparing food. I don’t know about you. I love food prep, I love going to the farmers’ market, I love everything around the process of food, but I have to say that sometimes it just gets old. I just get really immersed in what I’m doing, and I’m a really passionate, pretty intense person, and so when I get wrapped up in something and I really dive in, the idea of stopping to eat is sometimes not that appealing. And I think there’s something to be said for that as well. There’s some freedom — for me, at least — that comes from not being tied to a schedule of, like, OK, at 8:00 I have to eat breakfast, and at 12:00 I have to eat lunch, and at 7:00 I eat dinner. That kind of schedule and routine, while I generally stick to it because it’s grounding for me and because I’m intense and can easily kind of get so immersed in something that I just forget about everything else, having that routine normally is good me, but it’s also liberating to not be tied to that and to have days where I just have a completely different schedule of food intake, if only for that reason.

Steve Wright: Oh, yeah. I think most people who get more connected to their food and spend more energy on it every once in a while have that moment of, like, wow, this is amazing. I have to eat every day to live, but I’m really not into it right now.

Chris Kresser: Yeah, you’re like, wait, I just… Really? Again?! I just cooked and ate breakfast, and now I’m just about to cook and eat lunch. And wait, then I have to cook and eat dinner later. It can be a lot, especially because that’s not the only thing that most of us are doing during the day. Yeah. It’s just a sidenote, but it’s not really a sidenote because I think that we could call that a kind of spiritual aspect of intermittent fasting, too, where for some people who can get a little addicted to certain aspects of food or certain types of food or our relationship to food starts to feel a little bit out of whack, then intermittent fasting can be one way of resetting that. Or just fasting overall. In the past when I’ve done longer fasts either associated with meditation retreats or longer meditation retreats where I was only eating once a day, I found that to be really liberating and also really instructive. It really kind of shined the light on my relationship with food and certain aspects of that relationship that might not have been as healthy as I wanted it to be, so it’s a way of raising your awareness about how you relate to food, too, I think, which is really valuable.

Steve Wright: Oh, totally. It changed my world when I did a three-day fast six or seven years ago because I grew up and the feedback I got was always, you know, he’s a growing boy and has to eat all the time, and I did eat all the time and it felt great and food tastes wonderful, and so I had bought into the dogma about if I didn’t eat, all these negative hormone consequences would happen. And then there are all sort of priming hormones that can get set based on our rhythms, so if you normally eat around noon, it’s likely that your hormones will be primed for that meal at noon the next day. So I did a three-day coffee-and-water fast just to test it, and it was so amazing to realize, wow, I was just being primed by my environment, my past behavior. I’m totally fine.

Chris Kresser: Yeah.

Steve Wright: It was very liberating.

Chris Kresser: It is really liberating, and I recommend that everybody do that at least once because it can really kind of set you free from some habitual patterns and beliefs around food. I’ve found that to be really valuable.

Codi, hope that answers your questions. Everybody, keep you questions coming. We love hearing from you. Next time I’m going to have an announcement about the clinician training program, which is swimming along at a really increasingly fast pace, and I think we’re going to be starting preenrollment as early as mid August, so look forward to that for another announcement coming soon on the blog and then on the next podcast.

Steve Wright: Awesome, Chris. I know everybody’s waiting for that patiently, so that’ll be good.

In between episodes, if you would like to get your question answered, please go to ChrisKresser.com/PodcastQuestion to submit yours.

And also, if you’re not yet, make sure you’re following Chris on social media. Go to Facebook.com/ChrisKresserLAc or Twitter.com/ChrisKresser. If you’re following him on these modalities, it’s likely that you’ll find out about topics he may be going to write about or we may talk about on the show ahead of time and kind of get the latest access to what’s going on and what he’s thinking about. Thanks, everyone, for listening.

Chris Kresser: Thanks, everyone. Talk to you next time.

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Join the conversation

  1. I eat white rice as my main carb source for years. I start to feel extreme tiredness specially after meals this year and I cannot stand hungriness. (5-6 big meals in a day with white rice)

    Got some indigestion/gut problems 5 months ago. Feel so nauseous after eating.

    Checked my blood sugar levels and other things even including HIV/AIDS tests, had endoscopy and everything is okay. Still feel slightly nausea specially after eating but digestive enzymes really help me if I take them with meals. Water still gives me nausea/fatigue though.

    Well, I decided to start IF/Paleo way two days ago. I started to eat 2 meals a day (11-12/6-7)

    Hope that it helps me. Any suggestion are welcome.

    • Rice is very enzyme depleting. Maybe you’re producing less enzymes than you were. Try some digestive enzymes when you eat rice.

  2. I’m glad that there is a mention of who should NOT fast.

    I have fasted for one month and I do not regret it, but I do not think it helped my or my Lyme disease. At the time, I think it would have been more helpful for me to be “adding” than “subtracting” from my health.

    But I do see the benefits. Eating up all the extra waste sitting around until all the garbage is out sounds pretty nice.

  3. I joke about this ALL the time, actually: “ANOTHER meal?! I’m tired of cooking. Why can’t we just skip eating today?!” And wouldn’t it be liberating to do that on occasion…

    Meanwhile, my four children are not amused by my jokes, and neither do they ever want to skip breakfast (or lunch, or dinner!).

    My goal is to try intermittent fasting again someday, maybe during Motherhood Retirement. 🙂

  4. Do you have a link to the evidence about h pylori and hunger pains? I used to get those pains, but haven’t had them with recent fasts. I was treated for h pylori a while back. But how do you know it’s due to the h pylori?

    • I have h. pylori without symptoms I know of…..should I do the antibiotic treatment or leave it?

  5. I’ve been fasting 16-17hrs a day for about 15 months now. I’m 42 M (was healthy to begin with but muscle mass index getting low) and have to say it has been the most profound unbelievable change I have ever had in my life. Mentally I am sharper and no longer experience stress or anxiety of any kind. This is hard to believe if you’ve known me my whole life. Literally nothing gives me stress anymore no matter what it is, it’s like water off a ducks back. My anxiety completely evaporated. Physically I used to have a decent physique in college but at 35yrs old it began to fade. I began to lose it and figured it’s just aging and not much I could do. I event worked out hard at the gym but made no gains or improved. THEN I started the daily 16-17hr fasting and everything changed. I started packing on muscle like I was 21 again I could not believe it (and I take zero supplements, I eat the same diet as before fasting). I put on 10kg of muscle mass in less than a year doing nothing different in my diet or workout routine, all I did different was fast 16-17hrs a day, I have a 6 pack and don’t even do ab exercises, it’s crazy. I think every middle aged man should be doing this! I have tried to post an image of myself so you know I am not making this up but the system will not let me post any links? 🙁

    Also, my stamina at the gym is like nothing I have experienced even in my youth. I do reps until I can’t do any more, then I do an extra 5 after that. I can just keep going and going hard out for an hour. I hope much more research is done on this. As for my docs report, I went to a cardiologist for a full checkup (treadmill test, echo cardiogram, ecg, etc) cardiologist said I’m top 1%. I had bloods and check up at docs and doc said I have BP and bloodwork of a healthy teenager. I’m sticking with it. My wife also thinks I’m not aging any more and my skin seems younger. Anyway, can’t recommend the daily fast enough. One size does not fit all but it sure works for me.

    • First of all, I congratulate you on your effort and your results. You make some extraordinary claims, and I would like to know more specifics. You claim to have gained 10kg of muscle mass in a year, yet your body has also changed in other ways. If you have leaned out at the same time as you have gained muscle, I am guessing you have not gained as much as 10kg in body weight, but have gained some weight, lost some fat and estimated your muscle mass gains at 10kg?

      Also, you are saying you did not change your exercise habits, but I am thinking that your performance improvements have led to you working both longer and harder in the gym, right?

      As for your nutrient timing practices, I would be interested in knowing when you are eating your meals, when you are working out, and if you have any estimation of your calories – carb/protein/fat intakes?

      I am involved in a book project where this would be of interest to evaluate.

      Thank you, and again – nice job!

    • I am so happy to read you gushing about IF and how life changing it has become for you. I also do approx the same amount of fasting daily as you do, I’m an almost 50 y o female, and it has improved my life 1000%.
      My emotions are so even I feel so Zen that I have to pinch myself, I’ve lost about 24 lbs with about 20 to go but I don’t even care how long it takes because I’ll eat this way for the rest of my life. After spending my whole adulthood yoyo dieting, food ( good and bad) had become so emotionally charged that it felt as though I would never have food “peace”. Now food has become completely neutral for me. When I start to tell people about it I’m so enthusiastic I swear they think I’m going to end the conversation with an MLM pitch. Anyway it sure is nice to hear someone else who has experienced such results.

    • Your results with IF parallel mine. I eat in a 30 minute window once per day. Once/twice per week I extend to (one meal) 48 hours.

      Equanimity of mind might be derivative of increased levels of BDNF. Like you, I feel no stress, even if the environment is stressful.

      HIT: strength and speed maintained/enhanced. Washboard abs. I have never done a crunch/sit up. I can rattle off 15 pull ups effortlessly.

      Happy to see a guy who is getting the kind of results I’m getting.

      Less time spent thinking about, preparing, and shopping for food. Eating is inextricably linked to entertainment/positive social contexts/boredom for the vast majority of people. If you have the self-restraint/discipline/vision, IF makes life so much more effortless.

      Why let your physiological age outpace your chronological age?

      Find what works for you. As Bert Herring said, “the study of one.”

  6. I have been fasting for last 5 years. It became my lifestyle. I was feeling great. Never had issue until everything felt apart when i went to doctor and did routine blood work. All results looked good but i asked for thyroid antibodies test as my dad has hashimoto. It turned out I tested positive.. I felt apart mentally, I started AIP diet to see if I can fix it. My antibodies went up from 90 to 500 on AIP diet. I was super strict, never cheated. I wish i would never go to the doctor as I was feeling great and did not have any symptoms. Stupid I, should never asked for blood work. Now I live knowing that my body has antibodies and is destructing my thyroid without any symptoms. I went the functional medicine route and I found out that I have EB Virus reactivation. I hope supplements will help, but it seems like it is game over and Hashimoto will stay forever with my and I will always have to be on diet. The worse is to have the autoimmune disease and don’t have any symptoms except on the blood work. I am trying to treat some silent disease. It is a nightmare. It feels like being marked for destruction with no ETA.
    I want to get back to fasting but on AIP diet i lost 20 pounds and cannot regain it back. My body was reprogrammed to keep my new weight. I am 159 pounds now at 6.1. When I was fasting and happy I was 178 pounds. I miss fasting so much.
    Chris, I wonder, do you have patients that are healthy, no symptoms but do have thyroid antibodies?
    Is it possible that my body can have antibodies and I will never developed full blown Hashimotos?
    I wonder if some people can just have antibodies and have healthy thyroid for their whole life?
    Can you have big antibodies number, but your immune system actually is not destructing anything?

  7. I am a 65 year old active female. I play tennis, lift weights and do core exercises on a routine basis. Last year, I read about how intermittent fasting makes your body burn fat more efficiently and improve your blood sugar and lipids. I wanted to see for myself if my blood work numbers would change, so I took the 5 week challenge of cutting out all sugar except fruit and employed intermittent fasting 3 times a week.

    I didn’t change my diet at all because I already had a healthy diet. I fasted on Monday, Wednesday, and Fridays by eating my dinners at 5:30 PM and not eating until next day at 11:30 AM or after. Between 11:30 and 5:30, I ate pretty much what I wanted. I worked out on the days I fasted and did not notice any decline in my energy. I had blood work done after the 5 weeks and the numbers were staggering.

    My blood glucose went down from being in the 90’s to 77. Triglycerides went down from being in the 90’s to less than 45. Total cholesterol went from 224 to 183 with HDL in the 60’s and LDL went from 135 to NA. I believe this was all due to no sugar and intermittent fasting. I only lost few pounds because I ate more nuts than usual during that time.

    I think I could have continued intermittent fasting but I really didn’t have the need. I’m convinced if I need to address the blood sugar and lipid markers, I know how I can do it.

  8. I just left a post about how I did my intermittent fasting. first, I did it on my own, no blood testing or Dr recommendation. I realize that could be bad for someone with autoimmune disease, but I figured, at my age, just let me loose 20 pounds and I will be happy! I also will tell you that I basically followed the autoimmune Paleo diet, with one fresh green smoothie a day, usually as soon as I got home from work! I also grow my own organic garden with chard, kale, spinach and beets! And I only eat organic and grass fed meats, So I was eating a really nutritious diet! I not only lost the weight, but after about
    3 weeks on this, I found I had more energy, and I joined a health club and began working out AFTER work. No one ever told me a 69 year old could form muscles! The autoimmune stuff IS much better as I think I have just beat Collagenous Colitis. My Dr told me ther is no cure. . . . .

  9. Not a bad speculative discussion, but don’t you have any actual info from good studies. Are you sure that coffee and cream does not disturb intermittent fasting?? I would think that the body would be in a mild stress state and thus very receptive to any dose of calories or nutrients to stand down from up-regulating autophagy. But I am speculating. I really want to see hard data on this intermittent fasting.

    I dose with vitamins, minerals, aminos, and enzymes three times a day (and feel 40 years younger). My specific question is what stops the autophagy or other benefits of intermittent fasting: is it calories or nutrient density? You need to not eat for at least 16 hours to get the benefit (after 8 hours glycogen stores are depleted). Will coffee and cream
    (calories) stop the benefit? Will a dose of vitamins (nutrients) stop it? Without better information we may be kidding ourselves about doing ourselves good. How much better is it to IF for 20 + rather than 16 hours? Is the benefit curve linear, exponential, or U shaped? These are important questions.

    Regarding autophagy, I once got my D3 ng/ml up to 150 for a few of months and felt really good. All the accumulated health issues from past decades went away because D3 up-regulates autophagy as well as other good things. For example, an inch diameter welt about 1/4 inch high on my shoulder that I had for decades totally flattened. Others have reported similar results with high D3 ng/mg. I was recently taking 10,000 IU D3 with 50,000 of Vitamin A but my D3 plummeted to 30 ng/ml. – even though I also get lots of sun. So I think the D3 and A mitigate each other (read Chris Masterjohn on A and D). Am now trying to get up to 80 ng/ml with 15,000 daily D3 and only 25,000 Vitamin A.

    IF is, I think, an especially good adjunct practice for all on a high fat, mod protein, low carb diet because it is easy. High fat really decreases the hunger drive. But if one is not hungry due to high fat, does one get the same benefit from IF? We need better information. Does anyone know if there are any really good studies available on IF.

  10. I wish I had to loose weight, it seems so straight forward, but I need to gain weight and I do not succeed at all even if I eat tons of sugar. I am 6 foot tall and weight only 131 pounds.

  11. I am a 74 y/o woman. I have been intermittent fasting for 6 hrs.daily for two years. One day a week I go for 8 hrs. I do not diet, but I am able to maintain my weight, blood sugar and lipid levels. I actually prefer this to eating 3 meals a day.

  12. Many moons ago, when I was around 20 years old I started fasting on Mondays, Wednesdays and Fridays. I wanted to lose weight and it was very effective. Whatever I had a craving for on a fast day I promised myself that I’d have it the next day. That worked great for weight loss and my 20 year old body handled it easily. One time I even went for 3 days – just for yuks – and it didn’t even faze me. Nowadays, I don’t think I would handle it well at all. Seems like now, when I skip a meal, I get light-headed or start to feel awful. I wonder if it’s possible to re-acquaint the body to fasting again… slowly…

    • I’m pretty sure it would be possible. Most of our far ancestors didn’t rely on 3 meals or more per day, so I’d say you’re pretty much ‘hardwired’ to fast.

  13. Hello,

    I am really enjoying all of the podcasts and this one as well. I am still left wondering though about a big part of her question, which seemed to slip through the cracks- which is the issue of how intermittent fasting affects women differently from men. I am drawn to the idea, but I would hate to find out that I was adversely affecting my system. What are the differences and how can we know if, a a woman, this practice can still be beneficial (aside from the items outlined in the general guidelines). Thank you.

    • From what I’ve seen in my practice, women are typically more likely to be affected adversely from IF than men. There are several potential explanations for this, including differences in hormones/HPA axis function, higher rates of thyroid disease, etc. But ultimately trial and error is the only way to know for sure.

  14. Great conversation about how not one diet, exercise, anything fits all. Like it was mentioned above, intermittent fasting is not going to feel good or be beneficial if you are tired, stress, have adrenal fatigue, ect. Why? Because based on Chinese Medicine you will have to tap into your Essence (reserve or energy/adrenals) to come up with the energy to function and it will deplete you even more. If you have enough energy and is balance, then yes, because you will be using all that extra energy instead of “borrowing” from your reserves. Thanks Chris Kresser for always pointing out individuality and being able to listen/feel our bodies.

  15. The article doesn’t mention one benefit of IF – it shifts your body from cell growth mode to cell repair mode. This is according to a BBC science documentary (Horizon) which I saw a couple of years ago. There is some evidence this can help stave off dementia, amongst other things.

    • Very interesting article in the journal Aging, vol.6, No. 9 regarding research from UCLA describing a therapeutic program leading to reversal of cognitive decline. Intermittent fasting (12 hrs daily including 3 hrs prior to bedtime) is one component.
      With a history of significant dementia on my father’s side, it seems prudent for me to continue IF as part of my paleo lifestyle. Been using IF for several years with no ill effects. I’m a 73 yr old active woman with no chronic issues, thankfully.
      Link to article….

    • The technical term for “cell repair mode” is autophagy, which I did mention in the show. Check out that section of the transcript.

      • Thanks Chris! I hadn’t understood the term when I read the article. I did some research after. I wonder if ketosis would also upregulate autophagy? (And if so, if this might be kinder on some people’s systems than IF). It might help explain why ketosis can help with neurological and autoimmune problems. I don’t feel I got on well with IF but have been considering trying ketosis.

  16. I would love to intermittent fast and have given it a go to try and help my IBS. I’ve heard that some people have great success from the rest their gut gets. But I can’t do it when I am working. I can only do it if I sit around home hardly moving. There is just no stress resilience when I am in a fasted state. So I am watching research into fasting with interest. I did a 3 day fast at one stage under my doctor’s supervision and on the 2nd and 3rd I had extreme blood sugar crashing and had to be very careful to get electrolytes into me (which helped). No lasting results for my gut (I’d hoped to starve the bad bacteria). No fun at all but you will try anything when your gut is so uncomfortable. I am not doing any fasting at present and it annoys me when people say they get heaps of energy when they fast!

    • I was 69 yes old when I saw a post from Dr. Mercola. I checked into it a little further. At the time I was working 3 days a week, and I thought those 3 days would be perfect for trying it! I do have autoimmune disease, thyroid problems, etc., but decided to give it a go. I was amazed! I did not get hungry until about 11 am! At that point I thought about having lunch, and it was actually 11:30 by the time I did that. Since I prefer “brown bagging” I had total control of what I had for lunch and brought nutritious foods. Within 3 months, I had lost 24 lbs. it was virtually painless, and I called it my ” no brainier” diet. But you do have to be prepared and have good nutritious foods at both meals! And then, just work while you wait, for your body will tell you it is ready for food!

    • 2 thoughts, maybe you are not having enough fat in the meal before the fast (augment from avocado, olive oil, coconut oil, real fat from pig/ sheep/ beef. Secondly, take probiotics, gherkins, sauerkraut etc to support the gut bacteria.
      Also, I find fasting from after supper to breakfast (nearly 10 hours) to early lunch/late breakfast (about 10 to 14 hours) is OK for me.

    • I recently cured 3yrs of terrible post infectious ibs with a diy fecal transplant. Over the moon, I have my life back!

      • Hi i just read your comment. I have had severe IBS for 2.5 years with a great history with antibiotics, antibiotic infusions, parasites, stomach ulcer etc. Could you tell me about the fecal transplant? Looking into it as nothing has worked…?

  17. You mention that coffee and cream in the morning is still fasting. I know that Dave Asprey claims his bulletproof coffee with MCT and butter does not break the fast as well. Could you elaborate? Is it just the lack of protein that allows autophagy to continue or is fat in the am, truly a legitimate part of a fast?

  18. I really loved IF….until I began having trouble sleeping. My symtoms were nightmares, pounding heart wakeups, daytime stress with no logical cause. Adrenal issues? I don’t know, but I added tubers to my diet, which had been vlc, and ate more frequently. Symtoms are rare now, but I’ve added some pudge. Maybe leftover from not sleeping. I’m 65, female, T2 diabetic, hypertensive and my exercise is mild because of arthritis. My favorite quote is “Old age isn’t for sissies!”

    • You could try the 5:2 diet. A daily fast interfered with my wife’s hormones but she is great on 5:2 and looking/feeling fantastic.