10 ms·

Intermittent fasting strategies and their effects on body weight

101 points by lxm 1y ago

mrandish 1y ago
N=1 but in 2017 I lost over 100 pounds in 8 months by changing to a keto + IF diet and I've kept it off. I lost 10 pounds in 10 days and 20 pounds the first month. At around six weeks I became 'fat-adapted', a long-term metabolic transition to primarily burning fat instead of carbs (glucose) for energy. I didn't start with IF but at around that point I sort of fell into intermittent fasting because it just felt right. I'd heard about IF but never had it as a goal because it seemed impossible since I'd been hungry my whole life. But limiting carbs with keto controlled my blood sugar to the extent I was almost never hungry which made IF trivially easy. So if you're trying IF and struggling with hunger pangs, try managing blood sugar by reducing carb intake. The combination of Keto+IF worked so well for me, for a while my calorie tracking switched from the usual preventing eating too many calories to ensuring I was getting enough, which was certainly never on my bingo card. After a lifetime of being a slave to hunger it was liberating to suddenly feel effortlessly in control of diet and my relationship with food changed completely. Then at around 90 days my palate shifted, meaning I even lost my taste for carbie foods. If I tried a small bite of something carb-laden that I'd loved my whole life, it didn't even taste particularly good to me anymore. I also became hyper-sensitive to sugar. Sugar-soaked foods just taste poisonously over-sweetened (which they kind of are). A slice of apple now tastes as sweet as I'd ever want, like a dessert that has extra sugar-added. In the 8th month I reached below my ideal 'dream' weight and even saw abs appear for the first time in my life! I transitioned to maintenance mode but stayed keto because being in a blood sugar controlled state felt so amazing and not just physically but also mentally and emotionally. At around a year I went from strict keto to low carb for life which I still am 8 years later. When I started that was unimaginable. I saw keto as an onerous regimen that I'd endure if it worked and stop the second I wasn't overweight. But during the journey my metabolism, palate and food preferences changed so dramatically, I was basically a different person when I arrived. Those first few months when I was rigorously tracking every calorie in an app and managing intake with measuring cups and a kitchen scale felt like a burden but were actually invaluable skill-building. After a few months all that process became automatic so I didn't need to constantly track and by six months I got to the point where I don't even think about it consciously. That early rigor helped me get so in sync with my body and able to sense where my metabolism is in its natural cycles that now I just eat when necessary and convenient for my schedule. This often ends up being IF but it's not intentional on my part, which makes me think maybe IF patterns evolved in the hunter/gatherer era as part of our natural biological rhythms. Due to habit and carb-laden factory foods I'd never been able to access those rhythms until I made the conscious effort to break the patterns I'd been raised in.
- xianwen 1y ago
  Hi. Could you maybe share the keto and the low carb diets that you use(d)?
  - mrandish 1y ago
    Keto is different in that there's not really a "keto" diet, just the principle of limiting carb intake to under 20 grams/day. "Low Carb" isn't a well-defined term but most people take it to mean under 100g of carbs/day. Thus, there's a huge variety of ways to do keto depending on your lifestyle and food preferences. I did a lot eggs, meats and cheese because I like those. I suggest you read the FAQ of the Reddit keto forum: https://www.reddit.com/r/keto/wiki/faq https://www.reddit.com/r/keto/wiki/faq. I recently posted my personal "Keys to Keto Success" learned during my 8 month weight loss 8 years ago: https://news.ycombinator.com/item?id=44685689 https://news.ycombinator.com/item?id=44685689 which includes some effective hacks I discovered. The biggest thing is to do keto rigorously. It's different than most any other diet because it's not just about reducing calories. The power of keto is 100% in cutting carbs, which is why I advise "Cheat all you want on calories but never (ever) on carbs". For me, cutting calories on any diet was always difficult, painful and exhausting. Keto worked because I only focused on cutting carbs. Once I got my blood sugar under control by limiting carbs, my raging hunger just evaporated and the calories pretty much took care of themselves. The change was dramatic. After the first month I was no longer tracking calories to stop over-eating but instead to ensure I was getting enough :-). During the second month there was a point where I was slightly concerned I might be losing weight too fast because I was never hungry, which was certainly never something I'd imagined would be a problem for me. Of course, that's easily addressed by increasing calories a bit. There's just one thing to watch out for as you do keto. On keto you're able to eat a lot of fats which are very filling (and delicious). This is wonderful but it's only possible because having almost no carbs puts you in a ketogenic state where instead of burning glucose (carbs) for energy as you do now, your body burns those fats for energy instead of storing them (weight gain). So, unlike a normal calorie-reduction diet, where you can slip one day and just get back on the wagon the next day, cheating on carbs during keto will convert all that delicious fat you're eating into not only pounds of weight but potentially into all the bad stored fat related things like vascular plaque etc. So, basically, keto is the one diet where cheating doesn't just "delay your weight loss another day", it changes from magically protecting you from the negative effects of eating huge amounts of fat to actively making it much worse. Eating all that luscious fat thinking you're protected by Keto but then regularly cheating on carbs "just a little" (as many do on other diets), is pretty much the worst diet imaginable. You'll turbo-charge weight gain AND all the negative effects of excess fat consumption (cholesterol, lipids, A1C, etc). Theoretically, aggressively eating keto-levels of fat but NOT being in a ketogenic state to burn it off could, given time, make you pre-diabetic and your lipid blood panels will freak your doctor out. So, IMHO, keto is wonderful but there's just one unbreakable rule. You really, really can't cheat on keto (even a little). When I first understood this I was a little concerned but as I researched more it made complete sense. Keto isn't magic. With all these benefits of easy weight loss and healthy metabolism of course there's a potential downside to avoid. Now you know what it is - so go in with eyes wide open. For me, the stringent, "can't cheat, ever" (on carbs) aspect of keto was actually a psychological benefit. It made it 100% binary and thus easy to fully commit. I'm either really doing this or I shouldn't bother. Putting tangible health consequences on regularly "slipping just a little" actually helped me stick with keto rigorously during the first few weeks of transition and habit change (which is really the only hard part, after 30 days keto gets much easier). But you may be different, so you just need to decide if you can really commit 100% for the first ten days. If you manage that, then set your goal to finish the month. The rest really is all downhill from there. If you're as overweight as I was, after the first month of strict keto your weight loss will be so obvious people will definitely notice. In the second month, my admin told me people at the office were asking her if I was "okay", like they were worried I had cancer or was on chemo :-). So I started sharing a little more widely that I'd changed my eating habits. At least nowadays most people have heard of keto.
1024core 1y ago
Every study ends with something along the lines of: Longer duration trials are needed to further substantiate these findings.
- pdxandi 1y ago
  I read that as needing funding. Somebody has to pay for the research. In order to get it funded, you have to show your research has a basis. My interpretation anyway.
bargainbin 1y ago
The takeaway here is that if you do “alternate day fasting”, that is you eat normally on one day then do not eat all the next, you will lose weight. I can’t believe that losing 3.5 days of caloric intake would result in weight loss. In other news, water is wet.
- fred_is_fred 1y ago
  Or if you just ate 50% less calories 7 days a week perhaps.
  - treetalker 1y ago
    My understanding is that, yes, the weight loss results end up being similar — but that the story is not so simple (or linear) because "true" fasting activates certain metabolic pathways (e.g., mTOR) that mere calorie reduction does not, and that those pathways have different effects, such as autophagy and others that increase lifespan in different ways.
  - physicles 1y ago
    As other commenters and TFA have pointed out, that “just” is doing a lot of heavy lifting
- m4r71n 1y ago
  Alternate day fasting normally means you eat up to 500 calories on your fasting day, but then eat more than usual on normal days. So on average if you eat 500 one day and 2500 another, that is no different than eating a restricted diet of 1500 every day. The finding here is that the former results in slightly more weight loss than the latter. That restrictions in calorie intake will result in weight loss is a given.
  - scns 1y ago
    > eating a restricted diet of 1500 Keeping this up is hard, many fail. Alternating normal eating with IF days is easier to do.
- 1y ago
BennyH26 1y ago
In our medical practice, we would use intermittent fasting as part of a comprehensive medical plan to increase longevity. There are studies which demonstrate this is beneficial, at least in Macaque monkeys. Weight loss was just a nice side effect.
- anon84873628 1y ago
  As Mike Israetel puts it, you don't want your body swimming in nutrients all day every day. Whether it's IF, deficit cycles, periodic deep fast -- they all seem to have the same effect, which is just to give the body a break for a bit.
strken 1y ago
I'm not sure that a reduction in body weight tells us all the relevant information. One of the possible downsides of fasting is loss of lean body mass, generally meaning muscle. This is a problem for older people in particular because it's harder to keep muscle as you age and because muscle protects from falls, frailty, etc.
- testing22321 1y ago
  If a person is obese or morbidly obese, losing weight is the number one priority to increase overall health, lifespan, quality of life, etc etc. Losing a bit of lean muscle mass along the way is not important compared to the huge health gains of losing the weight.
  - strken 1y ago
    I agree that losing body fat is the number one priority, but I wish the research would focus on that rather than the number on the scale. Losing a bit of lean muscle mass along the way is important for its own sake, and also because it's a confounding variable for what I actually want to know, which is how much fat (not weight) a person lost.
    - testing22321 1y ago
      Why does it matter? When it comes to long term health outcomes, losing weight is the only thing that matters.
- Someone1234 1y ago
  Weight loss is linked with some loss of lean body mass, regardless of the method used. Intermittent fasting has been shown to match any other calorie deficit in terms of lean body mass loss, rather than more as you're implying. Regardless of how you lose weight the advice is and remains: > Eat a minimum of 0.36 grams of protein per day, per pound of LEAN* body weight. Increasing to 0.5-0.7 grams of protein per day, per pound of LEAN* body weight for older adults or when undergoing weight loss. *LEAN is a vital detail for overweight people, they commonly miscalculate protein requirements due to this. The easiest way for overweight people to determine their requirement, is just find an "ideal body weight calculator" online, enter height and gender, and then multiply THAT figure by 0.5-0.7. For example a man who is 6' tall and 400 lbs should eat 62 grams of protein per day MINIMUM, but during weight loss 86-120 grams of protein per day. It is common, unfortunately, to read online people in this situation miscalculate this to 280(!) grams of protein per day which is incorrect and harms their weight-loss goals.
Almondsetat 1y ago
What all these diets are desperately trying to do is psychologically manipulate you into eating less by playing with your sense of fullness. For weight loss, thermodynamics cannot be beaten: eating at different times and in a different order does not matter.
- flyinglizard 1y ago
  You’re assuming the body is a constant machine that metabolizes at a fixed rate but that can’t be true.
  - tekla 1y ago
    Until the human body becomes capable of creating energy out of nothing, this is irrelevant
    - californical 1y ago
      It can use different amounts of energy depending on different stimulus. Things like fidgeting and body temperature can make a pretty decent difference
      - anon84873628 1y ago
        Just to add some color for folks, this is referred to as NEAT in the literature: Non-Exercise Activity and Thermogenesis. When caloric intake is reduced, the body can decrease this type of expenditure without the person even realizing it.
    - objektif 1y ago
      Very bad take. What if our bodies adjusts the burn rate based on when we eat when we exercise? if that is true you can potentially eat more and lose more weight.
      - tekla 1y ago
        Irrelevant, energy out > energy in, you lose weight
wenc 1y ago
I've been doing intermittent fasting (16:8) since 2016 (9 years). I have a belly and am what you would call "a little chubby". I don't exercise that much (once a week). I drink one black coffee in the morning. After all these years of IF, net-net I haven't lost any weight, but I find if I stop IF (i.e. I start eating 3 meals a day), I feel sluggish. So in the absence of doing anything else, at least IF keeps my mind sharp. p.s. the only times I've lost weight is when I've fasted once a week, cut out 50% of all carbs from diet, and starting lifting weights. I lost water weight at first, then plateaued because I gained muscle, then after that muscles did the work of burning excess calories. I was that way for at least 3 years. Then I decided I loved food too much and added certain carbs back into my diet. These days I just do IF and nothing else, and my weight is stable.
- taeric 1y ago
  Did you keep up the weight lifting?
- alexey-salmin 1y ago
  You can try long-distance running. 100km a week allows you to indulge extra 5000-8000k calories. I also enjoy food and always ate a lot (like 2 meals at lunch), and I was thin all the way up to 30 thanks to fast metabolism I guess. If I didn't start running 5 years ago my choice would be between severe cuts to my diet or obesity.
  - AstroBen 1y ago
    Getting into cycling actually has me about to stop intermittent fasting. I go out and can burn 1200 calories in a few hours and that's hard to make up with an 8-hour eating window unless I want to start eating a bunch of junk food. Not trying to lose any more weight
    - rkomorn 1y ago
      Cycling 10-12 hours a week (and going pretty hard at it thanks to the many hills in the Bay Area) let me eat just about everything I wanted while still losing weight. If you have the time and enjoy it, there's no better way to be able to stuff yourself silly.
garrickvanburen 1y ago
After briefly looking into it, my assumption is intermittent fasting works great for people that are eating throughout the entirety of the day.
- abracadaniel 1y ago
  I’ve often wondered about this. If you have a sugary drink, would it be better to drink it in one sitting or sip it throughout the day.
deleted 1y ago
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lkrubner 1y ago
I have read that before the Industrial Revolution, most people faced famine for about 10% of their lives. And while, historically, that would have probably been concentrated into a few bad years during their lifetime (months of starvation, during a few bad years), if we were to generalize that and make it a rule, it would work out to 3 days a month. There is some evidence that there are health benefits that are specific to the fasting mode. This has mostly been studied in the context of chemotherapy, where fasting can protect against some of the side-effects of chemotherapy: https://pmc.ncbi.nlm.nih.gov/articles/PMC5870384/ https://pmc.ncbi.nlm.nih.gov/articles/PMC5870384/ Most of this has only been studied in animals, not humans, but in animals the results were clear: "Fasting before chemotherapy (CT) was shown to protect healthy cells from treatment toxicity by reducing the expression of some oncogenes, such as RAS and the AKT signaling pathway [2]. This reduction is mediated by the decrease of circulating insulin-like growth factor 1 (IGF-1) and glucose. In addition, starvation and calorie restriction activate other oncogenes in cancer cells, induce autophagy, and decrease cellular growth rates while increasing sensitivity to antimitotic drugs [2]." If we assume that we have been shaped by millions of years of frequent famine, then our evolution has been shaped by famine. It is possible that our immune system simply makes the assumption that we will soon face famine, and therefore some important tasks, such as extreme autophagy, are normally postponed till the famine arrives. However, in the modern era the famine never arrives, and so we may have to induce it by artificial means. I have experimented with very long fasts. My longest fast ever was in September of 2015 when I managed to go 12 straight days on nothing but water. Obviously, any health benefits from that incident might have been psychosomatic, since I was expecting health benefits. But all the same, I did find some of the health benefits to be shocking and completely unexpected. Since at least 1995, and possibly 1990, I had a mole on my skin on my left arm. I wasn't worried about it, so I simply ignored it. I had it on my arm at least 20 years, maybe 25 years. I recall one morning in November of 2015 when I was in my kitchen, making breakfast, and I reached over to pour myself some coffee, and of course my arm was in my field of vision, and after a moment of thinking something was different, it occurred to me that the mole was gone. It had been there at least 20 years, and then it disappeared, at some point during the weeks after I had done the 12 day fast. I don't know when it disappeared, it just slowly faded away at some point between September and November. There was no remaining sign of it on my arm. Again, that might have been purely psychosomatic, but it was interesting.
knowitnone2 1y ago
I did intermittent fasting. I think this conditioned me to being in the hunger state and to ignore hunger. Along with exercise and portion control, I did lose 20 pounds. I could have gone further but I became lacking in certain nutrients and a doctor told me to stop.
keiferski 1y ago
In my experience IF is better thought of as a way to break bad eating habits, not as a direct way to lose weight. Merely eating the same amount of food but in a certain time frame (which is what a lot of people end up doing) doesn’t accomplish much in terms of weight loss. But I have found it successful in breaking bad habits, which results in weight loss indirectly. For example, I had a bad habit of eating a large breakfast 1-2 hours within waking up. I was never really that hungry, but it was just something I did out of habit. Doing an IF routine made me realize that I’m not actually that hungry in the morning and can get by until 10-11am on just a coffee with milk.
- throwaway290 1y ago
  Coffee with milk is not breaking IF?
  - keiferski 1y ago
    I didn’t elaborate enough in my comment. Basically I mean that I stopped eating breakfast with IF and then gradually realized a coffee with milk was enough to serve as a replacement. The point being that rigidly sticking to IF rules is less useful than just using it as a way to reset your eating habits. (At least in my experience.)
  - paulpauper 1y ago
    calories= breaking the fast
- somenameforme 1y ago
  I'd agree and generalize that intermittent fasting is a great way to remind yourself that that feeling in your stomach when you get hungry doesn't mean you need to eat now. In fact, there's no real rush whatsoever. The first time I did a 24 hour fast, it was brutal and I treated myself to a feast at the end which I rapidly gobbled down. After doing intermittent fasting for a few years, I have accidentally fasted for 24+ hours multiple times. And after you do it for a while, it makes it clear that this whole modern thing of 3 meals a day, let alone with snacking, is really just weird.
- 1y ago
mrbonner 1y ago
I’m curious whether taking the oral form of Ozempic at a lower dose could have effects similar to intermittent fasting, given that it may lead to skipping a meal as well.
- kaycebasques 1y ago
  Microdosing ozempic
  - gorfian_robot 1y ago
    Diet Coke now with GLPs?
surfsvammel 1y ago
I diet, on and off. Keeping fat free weight as the highest priority (I don’t want to loose hard earned muscle)! I’ve tried all types of diets. For me, the most important for me is to save the biggest meal for late in the day. I can easily go hungry a couple of hours during the day if I know there is a filling meal coming. I suspect IF works in a similar way.
- sebazzz 1y ago
  > For me, the most important for me is to save the biggest meal for late in the day. Wouldn't the big meal be stored as fat during sleeping?
bonvoiay 1y ago
It surprises me how often the basic physiology still gets overlooked. Hunger is driven by hormonal signals designed to defend a set point. Even if you consciously fast for most of the day, your brain will push you to make up the difference once you start eating. When it comes to fat loss, it still boils down to maintaining a caloric deficit — timing alone won’t keep your appetite in check for long. We’ve known this for years. IF may have other potential benefits — better insulin sensitivity, longevity, or improved adherence for some people (since avoiding food most of the day can be psychologically easier) — but none of that is “new” anymore.
porridgeraisin 1y ago
Practical advice for people who do normal 80/20 healthy/unhealthy stuff and don't wanna think: Now and then like twice a month, skip 2/3 meals in the day. If hard, have light juices/even fruits. Think of it as giving your digestive system "rest". Don't do it when otherwise sick. It will make you generally healthier, no drastic changes. Those require drastic measures which differ person to person.
sublinear 1y ago
I lost 130 pounds over the course of 2 years in my late 20s by skipping lunch every other day and entirely skipping breakfast. I also started tracking my calories and macros. I don't know what to call that, but it worked and it changed my relationship with food forever (in a good way). I have since kept the weight off and switched back to eating 3 meals a day with a better understanding of how much and of what to eat. Eat a lot more protein and way less carbs. Most meats already have the right balance of fat included, so avoid adding more. Fill up on fibrous vegetables since they don't really count towards calories and help digest all the meat you'll be eating. Drink plenty of water, sleep well, and at least hit your daily steps and heart rate targets if you're not huge on exercise. Building muscle is a good idea, but I'm lucky I've never had a problem with that and just needed to lose the body fat. I'm now in my mid 30s and have a clean bill of health. When I was heavier I was prediabetic and my resting heart rate was 85. Now it's about 65 and blood sugar is good and doesn't spike or stay elevated all day anymore. It's good to get this stuff on track when you're still youngish. Oh also I stopped the intermittent fasting because it was messing with my blood sugar. That was why I wrote all this and it's my argument against it.

101 points by lxm 1y ago

N=1 but in 2017 I lost over 100 pounds in 8 months by changing to a keto + IF diet and I've kept it off. I lost 10 pounds in 10 days and 20 pounds the first month. At around six weeks I became 'fat-adapted', a long-term metabolic transition to primarily burning fat instead of carbs (glucose) for energy. I didn't start with IF but at around that point I sort of fell into intermittent fasting because it just felt right. I'd heard about IF but never had it as a goal because it seemed impossible since I'd been hungry my whole life. But limiting carbs with keto controlled my blood sugar to the extent I was almost never hungry which made IF trivially easy. So if you're trying IF and struggling with hunger pangs, try managing blood sugar by reducing carb intake. The combination of Keto+IF worked so well for me, for a while my calorie tracking switched from the usual preventing eating too many calories to ensuring I was getting enough, which was certainly never on my bingo card. After a lifetime of being a slave to hunger it was liberating to suddenly feel effortlessly in control of diet and my relationship with food changed completely. Then at around 90 days my palate shifted, meaning I even lost my taste for carbie foods. If I tried a small bite of something carb-laden that I'd loved my whole life, it didn't even taste particularly good to me anymore. I also became hyper-sensitive to sugar. Sugar-soaked foods just taste poisonously over-sweetened (which they kind of are). A slice of apple now tastes as sweet as I'd ever want, like a dessert that has extra sugar-added. In the 8th month I reached below my ideal 'dream' weight and even saw abs appear for the first time in my life! I transitioned to maintenance mode but stayed keto because being in a blood sugar controlled state felt so amazing and not just physically but also mentally and emotionally. At around a year I went from strict keto to low carb for life which I still am 8 years later. When I started that was unimaginable. I saw keto as an onerous regimen that I'd endure if it worked and stop the second I wasn't overweight. But during the journey my metabolism, palate and food preferences changed so dramatically, I was basically a different person when I arrived. Those first few months when I was rigorously tracking every calorie in an app and managing intake with measuring cups and a kitchen scale felt like a burden but were actually invaluable skill-building. After a few months all that process became automatic so I didn't need to constantly track and by six months I got to the point where I don't even think about it consciously. That early rigor helped me get so in sync with my body and able to sense where my metabolism is in its natural cycles that now I just eat when necessary and convenient for my schedule. This often ends up being IF but it's not intentional on my part, which makes me think maybe IF patterns evolved in the hunter/gatherer era as part of our natural biological rhythms. Due to habit and carb-laden factory foods I'd never been able to access those rhythms until I made the conscious effort to break the patterns I'd been raised in.

xianwen 1y ago
Hi. Could you maybe share the keto and the low carb diets that you use(d)?
- mrandish 1y ago
  Keto is different in that there's not really a "keto" diet, just the principle of limiting carb intake to under 20 grams/day. "Low Carb" isn't a well-defined term but most people take it to mean under 100g of carbs/day. Thus, there's a huge variety of ways to do keto depending on your lifestyle and food preferences. I did a lot eggs, meats and cheese because I like those. I suggest you read the FAQ of the Reddit keto forum: https://www.reddit.com/r/keto/wiki/faq https://www.reddit.com/r/keto/wiki/faq. I recently posted my personal "Keys to Keto Success" learned during my 8 month weight loss 8 years ago: https://news.ycombinator.com/item?id=44685689 https://news.ycombinator.com/item?id=44685689 which includes some effective hacks I discovered. The biggest thing is to do keto rigorously. It's different than most any other diet because it's not just about reducing calories. The power of keto is 100% in cutting carbs, which is why I advise "Cheat all you want on calories but never (ever) on carbs". For me, cutting calories on any diet was always difficult, painful and exhausting. Keto worked because I only focused on cutting carbs. Once I got my blood sugar under control by limiting carbs, my raging hunger just evaporated and the calories pretty much took care of themselves. The change was dramatic. After the first month I was no longer tracking calories to stop over-eating but instead to ensure I was getting enough :-). During the second month there was a point where I was slightly concerned I might be losing weight too fast because I was never hungry, which was certainly never something I'd imagined would be a problem for me. Of course, that's easily addressed by increasing calories a bit. There's just one thing to watch out for as you do keto. On keto you're able to eat a lot of fats which are very filling (and delicious). This is wonderful but it's only possible because having almost no carbs puts you in a ketogenic state where instead of burning glucose (carbs) for energy as you do now, your body burns those fats for energy instead of storing them (weight gain). So, unlike a normal calorie-reduction diet, where you can slip one day and just get back on the wagon the next day, cheating on carbs during keto will convert all that delicious fat you're eating into not only pounds of weight but potentially into all the bad stored fat related things like vascular plaque etc. So, basically, keto is the one diet where cheating doesn't just "delay your weight loss another day", it changes from magically protecting you from the negative effects of eating huge amounts of fat to actively making it much worse. Eating all that luscious fat thinking you're protected by Keto but then regularly cheating on carbs "just a little" (as many do on other diets), is pretty much the worst diet imaginable. You'll turbo-charge weight gain AND all the negative effects of excess fat consumption (cholesterol, lipids, A1C, etc). Theoretically, aggressively eating keto-levels of fat but NOT being in a ketogenic state to burn it off could, given time, make you pre-diabetic and your lipid blood panels will freak your doctor out. So, IMHO, keto is wonderful but there's just one unbreakable rule. You really, really can't cheat on keto (even a little). When I first understood this I was a little concerned but as I researched more it made complete sense. Keto isn't magic. With all these benefits of easy weight loss and healthy metabolism of course there's a potential downside to avoid. Now you know what it is - so go in with eyes wide open. For me, the stringent, "can't cheat, ever" (on carbs) aspect of keto was actually a psychological benefit. It made it 100% binary and thus easy to fully commit. I'm either really doing this or I shouldn't bother. Putting tangible health consequences on regularly "slipping just a little" actually helped me stick with keto rigorously during the first few weeks of transition and habit change (which is really the only hard part, after 30 days keto gets much easier). But you may be different, so you just need to decide if you can really commit 100% for the first ten days. If you manage that, then set your goal to finish the month. The rest really is all downhill from there. If you're as overweight as I was, after the first month of strict keto your weight loss will be so obvious people will definitely notice. In the second month, my admin told me people at the office were asking her if I was "okay", like they were worried I had cancer or was on chemo :-). So I started sharing a little more widely that I'd changed my eating habits. At least nowadays most people have heard of keto.

1024core 1y ago

Every study ends with something along the lines of: Longer duration trials are needed to further substantiate these findings.

pdxandi 1y ago
I read that as needing funding. Somebody has to pay for the research. In order to get it funded, you have to show your research has a basis. My interpretation anyway.

bargainbin 1y ago

The takeaway here is that if you do “alternate day fasting”, that is you eat normally on one day then do not eat all the next, you will lose weight. I can’t believe that losing 3.5 days of caloric intake would result in weight loss. In other news, water is wet.

fred_is_fred 1y ago
Or if you just ate 50% less calories 7 days a week perhaps.
- treetalker 1y ago
  My understanding is that, yes, the weight loss results end up being similar — but that the story is not so simple (or linear) because "true" fasting activates certain metabolic pathways (e.g., mTOR) that mere calorie reduction does not, and that those pathways have different effects, such as autophagy and others that increase lifespan in different ways.
- physicles 1y ago
  As other commenters and TFA have pointed out, that “just” is doing a lot of heavy lifting
m4r71n 1y ago
Alternate day fasting normally means you eat up to 500 calories on your fasting day, but then eat more than usual on normal days. So on average if you eat 500 one day and 2500 another, that is no different than eating a restricted diet of 1500 every day. The finding here is that the former results in slightly more weight loss than the latter. That restrictions in calorie intake will result in weight loss is a given.
- scns 1y ago
  > eating a restricted diet of 1500 Keeping this up is hard, many fail. Alternating normal eating with IF days is easier to do.
1y ago

BennyH26 1y ago

In our medical practice, we would use intermittent fasting as part of a comprehensive medical plan to increase longevity. There are studies which demonstrate this is beneficial, at least in Macaque monkeys. Weight loss was just a nice side effect.

anon84873628 1y ago
As Mike Israetel puts it, you don't want your body swimming in nutrients all day every day. Whether it's IF, deficit cycles, periodic deep fast -- they all seem to have the same effect, which is just to give the body a break for a bit.

strken 1y ago

I'm not sure that a reduction in body weight tells us all the relevant information. One of the possible downsides of fasting is loss of lean body mass, generally meaning muscle. This is a problem for older people in particular because it's harder to keep muscle as you age and because muscle protects from falls, frailty, etc.

testing22321 1y ago
If a person is obese or morbidly obese, losing weight is the number one priority to increase overall health, lifespan, quality of life, etc etc. Losing a bit of lean muscle mass along the way is not important compared to the huge health gains of losing the weight.
- strken 1y ago
  I agree that losing body fat is the number one priority, but I wish the research would focus on that rather than the number on the scale. Losing a bit of lean muscle mass along the way is important for its own sake, and also because it's a confounding variable for what I actually want to know, which is how much fat (not weight) a person lost.
  - testing22321 1y ago
    Why does it matter? When it comes to long term health outcomes, losing weight is the only thing that matters.
Someone1234 1y ago
Weight loss is linked with some loss of lean body mass, regardless of the method used. Intermittent fasting has been shown to match any other calorie deficit in terms of lean body mass loss, rather than more as you're implying. Regardless of how you lose weight the advice is and remains: > Eat a minimum of 0.36 grams of protein per day, per pound of LEAN* body weight. Increasing to 0.5-0.7 grams of protein per day, per pound of LEAN* body weight for older adults or when undergoing weight loss. *LEAN is a vital detail for overweight people, they commonly miscalculate protein requirements due to this. The easiest way for overweight people to determine their requirement, is just find an "ideal body weight calculator" online, enter height and gender, and then multiply THAT figure by 0.5-0.7. For example a man who is 6' tall and 400 lbs should eat 62 grams of protein per day MINIMUM, but during weight loss 86-120 grams of protein per day. It is common, unfortunately, to read online people in this situation miscalculate this to 280(!) grams of protein per day which is incorrect and harms their weight-loss goals.

Almondsetat 1y ago

What all these diets are desperately trying to do is psychologically manipulate you into eating less by playing with your sense of fullness. For weight loss, thermodynamics cannot be beaten: eating at different times and in a different order does not matter.

flyinglizard 1y ago
You’re assuming the body is a constant machine that metabolizes at a fixed rate but that can’t be true.
- tekla 1y ago
  Until the human body becomes capable of creating energy out of nothing, this is irrelevant
  - californical 1y ago
    It can use different amounts of energy depending on different stimulus. Things like fidgeting and body temperature can make a pretty decent difference
    - anon84873628 1y ago
      Just to add some color for folks, this is referred to as NEAT in the literature: Non-Exercise Activity and Thermogenesis. When caloric intake is reduced, the body can decrease this type of expenditure without the person even realizing it.
  - objektif 1y ago
    Very bad take. What if our bodies adjusts the burn rate based on when we eat when we exercise? if that is true you can potentially eat more and lose more weight.
    - tekla 1y ago
      Irrelevant, energy out > energy in, you lose weight

wenc 1y ago

I've been doing intermittent fasting (16:8) since 2016 (9 years). I have a belly and am what you would call "a little chubby". I don't exercise that much (once a week). I drink one black coffee in the morning. After all these years of IF, net-net I haven't lost any weight, but I find if I stop IF (i.e. I start eating 3 meals a day), I feel sluggish. So in the absence of doing anything else, at least IF keeps my mind sharp. p.s. the only times I've lost weight is when I've fasted once a week, cut out 50% of all carbs from diet, and starting lifting weights. I lost water weight at first, then plateaued because I gained muscle, then after that muscles did the work of burning excess calories. I was that way for at least 3 years. Then I decided I loved food too much and added certain carbs back into my diet. These days I just do IF and nothing else, and my weight is stable.

taeric 1y ago
Did you keep up the weight lifting?
alexey-salmin 1y ago
You can try long-distance running. 100km a week allows you to indulge extra 5000-8000k calories. I also enjoy food and always ate a lot (like 2 meals at lunch), and I was thin all the way up to 30 thanks to fast metabolism I guess. If I didn't start running 5 years ago my choice would be between severe cuts to my diet or obesity.
- AstroBen 1y ago
  Getting into cycling actually has me about to stop intermittent fasting. I go out and can burn 1200 calories in a few hours and that's hard to make up with an 8-hour eating window unless I want to start eating a bunch of junk food. Not trying to lose any more weight
  - rkomorn 1y ago
    Cycling 10-12 hours a week (and going pretty hard at it thanks to the many hills in the Bay Area) let me eat just about everything I wanted while still losing weight. If you have the time and enjoy it, there's no better way to be able to stuff yourself silly.

garrickvanburen 1y ago

After briefly looking into it, my assumption is intermittent fasting works great for people that are eating throughout the entirety of the day.

abracadaniel 1y ago
I’ve often wondered about this. If you have a sugary drink, would it be better to drink it in one sitting or sip it throughout the day.

deleted 1y ago

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lkrubner 1y ago

I have read that before the Industrial Revolution, most people faced famine for about 10% of their lives. And while, historically, that would have probably been concentrated into a few bad years during their lifetime (months of starvation, during a few bad years), if we were to generalize that and make it a rule, it would work out to 3 days a month. There is some evidence that there are health benefits that are specific to the fasting mode. This has mostly been studied in the context of chemotherapy, where fasting can protect against some of the side-effects of chemotherapy: https://pmc.ncbi.nlm.nih.gov/articles/PMC5870384/ https://pmc.ncbi.nlm.nih.gov/articles/PMC5870384/ Most of this has only been studied in animals, not humans, but in animals the results were clear: "Fasting before chemotherapy (CT) was shown to protect healthy cells from treatment toxicity by reducing the expression of some oncogenes, such as RAS and the AKT signaling pathway [2]. This reduction is mediated by the decrease of circulating insulin-like growth factor 1 (IGF-1) and glucose. In addition, starvation and calorie restriction activate other oncogenes in cancer cells, induce autophagy, and decrease cellular growth rates while increasing sensitivity to antimitotic drugs [2]." If we assume that we have been shaped by millions of years of frequent famine, then our evolution has been shaped by famine. It is possible that our immune system simply makes the assumption that we will soon face famine, and therefore some important tasks, such as extreme autophagy, are normally postponed till the famine arrives. However, in the modern era the famine never arrives, and so we may have to induce it by artificial means. I have experimented with very long fasts. My longest fast ever was in September of 2015 when I managed to go 12 straight days on nothing but water. Obviously, any health benefits from that incident might have been psychosomatic, since I was expecting health benefits. But all the same, I did find some of the health benefits to be shocking and completely unexpected. Since at least 1995, and possibly 1990, I had a mole on my skin on my left arm. I wasn't worried about it, so I simply ignored it. I had it on my arm at least 20 years, maybe 25 years. I recall one morning in November of 2015 when I was in my kitchen, making breakfast, and I reached over to pour myself some coffee, and of course my arm was in my field of vision, and after a moment of thinking something was different, it occurred to me that the mole was gone. It had been there at least 20 years, and then it disappeared, at some point during the weeks after I had done the 12 day fast. I don't know when it disappeared, it just slowly faded away at some point between September and November. There was no remaining sign of it on my arm. Again, that might have been purely psychosomatic, but it was interesting.

knowitnone2 1y ago

I did intermittent fasting. I think this conditioned me to being in the hunger state and to ignore hunger. Along with exercise and portion control, I did lose 20 pounds. I could have gone further but I became lacking in certain nutrients and a doctor told me to stop.

keiferski 1y ago

In my experience IF is better thought of as a way to break bad eating habits, not as a direct way to lose weight. Merely eating the same amount of food but in a certain time frame (which is what a lot of people end up doing) doesn’t accomplish much in terms of weight loss. But I have found it successful in breaking bad habits, which results in weight loss indirectly. For example, I had a bad habit of eating a large breakfast 1-2 hours within waking up. I was never really that hungry, but it was just something I did out of habit. Doing an IF routine made me realize that I’m not actually that hungry in the morning and can get by until 10-11am on just a coffee with milk.

throwaway290 1y ago
Coffee with milk is not breaking IF?
- keiferski 1y ago
  I didn’t elaborate enough in my comment. Basically I mean that I stopped eating breakfast with IF and then gradually realized a coffee with milk was enough to serve as a replacement. The point being that rigidly sticking to IF rules is less useful than just using it as a way to reset your eating habits. (At least in my experience.)
- paulpauper 1y ago
  calories= breaking the fast
somenameforme 1y ago
I'd agree and generalize that intermittent fasting is a great way to remind yourself that that feeling in your stomach when you get hungry doesn't mean you need to eat now. In fact, there's no real rush whatsoever. The first time I did a 24 hour fast, it was brutal and I treated myself to a feast at the end which I rapidly gobbled down. After doing intermittent fasting for a few years, I have accidentally fasted for 24+ hours multiple times. And after you do it for a while, it makes it clear that this whole modern thing of 3 meals a day, let alone with snacking, is really just weird.
1y ago

mrbonner 1y ago

I’m curious whether taking the oral form of Ozempic at a lower dose could have effects similar to intermittent fasting, given that it may lead to skipping a meal as well.

kaycebasques 1y ago
Microdosing ozempic
- gorfian_robot 1y ago
  Diet Coke now with GLPs?

surfsvammel 1y ago

I diet, on and off. Keeping fat free weight as the highest priority (I don’t want to loose hard earned muscle)! I’ve tried all types of diets. For me, the most important for me is to save the biggest meal for late in the day. I can easily go hungry a couple of hours during the day if I know there is a filling meal coming. I suspect IF works in a similar way.

sebazzz 1y ago
> For me, the most important for me is to save the biggest meal for late in the day. Wouldn't the big meal be stored as fat during sleeping?

bonvoiay 1y ago

It surprises me how often the basic physiology still gets overlooked. Hunger is driven by hormonal signals designed to defend a set point. Even if you consciously fast for most of the day, your brain will push you to make up the difference once you start eating. When it comes to fat loss, it still boils down to maintaining a caloric deficit — timing alone won’t keep your appetite in check for long. We’ve known this for years. IF may have other potential benefits — better insulin sensitivity, longevity, or improved adherence for some people (since avoiding food most of the day can be psychologically easier) — but none of that is “new” anymore.

porridgeraisin 1y ago

Practical advice for people who do normal 80/20 healthy/unhealthy stuff and don't wanna think: Now and then like twice a month, skip 2/3 meals in the day. If hard, have light juices/even fruits. Think of it as giving your digestive system "rest". Don't do it when otherwise sick. It will make you generally healthier, no drastic changes. Those require drastic measures which differ person to person.

sublinear 1y ago

I lost 130 pounds over the course of 2 years in my late 20s by skipping lunch every other day and entirely skipping breakfast. I also started tracking my calories and macros. I don't know what to call that, but it worked and it changed my relationship with food forever (in a good way). I have since kept the weight off and switched back to eating 3 meals a day with a better understanding of how much and of what to eat. Eat a lot more protein and way less carbs. Most meats already have the right balance of fat included, so avoid adding more. Fill up on fibrous vegetables since they don't really count towards calories and help digest all the meat you'll be eating. Drink plenty of water, sleep well, and at least hit your daily steps and heart rate targets if you're not huge on exercise. Building muscle is a good idea, but I'm lucky I've never had a problem with that and just needed to lose the body fat. I'm now in my mid 30s and have a clean bill of health. When I was heavier I was prediabetic and my resting heart rate was 85. Now it's about 65 and blood sugar is good and doesn't spike or stay elevated all day anymore. It's good to get this stuff on track when you're still youngish. Oh also I stopped the intermittent fasting because it was messing with my blood sugar. That was why I wrote all this and it's my argument against it.