We can't answer this confidently, the way I would say it is: there isn't strong evidence to support the idea that either is better.
> Given my current understanding from all the intermittent fasting hype lately, it is indeed better to eat big meals rarely rather than small meals frequently. For some reason, your post got me slightly confused because I lack the necessary knowledge to have a proper model about nutrition in place.
The IF people (along with the Keto people) use a variety of tricks to try and prove their point. There is absolutely not a single paper showing calorically balanced food intake has different clinically significant outcomes. Period, full stop etc. There are tons of papers saying things like if you force people to eat in constrained windows they eat fewer calories (or if you force people to eat high fat diets they eat fewer calories etc.). Those are all useful outcomes: they are "compliance hacks." But they idea that any of these are significantly metabolically different is not at all supported by the science.
As for yourself: nutritional science is weak, and if the nutritional science says do something, and you observe a bad outcome in yourself from doing it, I'd take your own personal data over the nutritional science, frankly. For instance: fiber is a great modulator. If you go to a GI specialist and say "I'm having dietary issues," increasing fiber is usually the first thing they recommend. But also, sometimes that doesn't work and then the next thing is decreasing fiber (FODMAP diet). So it's really hard to make sweeping recommendations because the body is so complex and nutrition involves so many different cooperating systems that can all go slightly wrong.
This doesn't seem correct. IF has statistically significant benefits:
https://www.health.harvard.edu/blog/intermittent-fasting-sur...
(Supporting papers linked at the end)
> The IF people (along with the Keto people) use a variety of tricks to try and prove their point. There is absolutely not a single paper showing calorically balanced food intake has clinically significant outcomes. Period, full stop etc. There are tons of papers saying things like if you force people to eat in constrained windows they eat fewer calories (or if you force people to eat high fat diets they eat fewer calories etc.). Those are all useful outcomes: they are "compliance hacks." But they idea that any of these are significantly metabolically different is not at all supported by the science.
1. These papers do not show different outcomes with calorically controlled inputs, as I mentioned. One of the tricks used by the IF scientific community is to serve the same number of calories and so it looks like the same number of calories were consumed in the abstract. They never are, because if this did happen it would have massive implications for our understanding of the human body. It would require us to be wrong about a lot of things.
2. There is a difference between statistical significance (which could be, but has not been, shown in calorically controlled diets), and clinical significance (which definitely has not been shown in calorically controlled diets, and likely will not).
Yeah, welcome to medicine. If you've ever encountered these things in a non-theoretic perspective (i.e., having some condition), you quickly see that doctors don't know shit.
Perhaps not surprising, given that human experimentation is taboo.
Anyways, how does what you're saying mesh with the fact that extra glucose is stored in your body's reserves while ketones are secreted with urine and breath?
That is, unfortunately, exactly why I am so acquainted with this stuff, and yeah, it is pretty frightening to have doctors tell you they just don't know. But to be fair, I'm talking about being wrong about fundamental biology, not medicine, in which massive shake ups like that are far rarer. It's also not like this stuff hasn't been studied.
> Anyways, how does what you're saying mesh with the fact that extra glucose is stored in your body's reserves while ketones are secreted with urine and breath?
Not sure what you mean but fwiw glucose is also secreted in urine and breath.
It’s obviously not true that for any given set of calories consumed the body has only one option of what to do with them. It can build muscle, store fat, repair heart walls, excrete it, and so forth.
This is determined by a bunch of factors including hormones. So if hormonal balance or other metabolic behavior is modulated by macro (or micro) nutrient intake, then the calorie emphasis might be overly simplistic.
Yep, I would not suggest anyone take up a diet of pure sugar, only that if you are trying to use science to set your diet we aren't really confident, at the level of macros, about what makes a difference, but we are very confident about excess calories.
The way you are wording your comments, someone could come away feeling like these things aren’t really worth considering.
It’s like, your comments to me seem like you are technically correct but a person reading them might think “ok, this smart person said the Atkins diet doesn’t really work, it’s all sleight of hand.”
That could be counter productive, because the Atkins diet really DOES work for some people. Proving that it’s likely not working for the reason people think it is can be helpful for accuracy’s sake, but depending on delivery can just become discouraging.
The missing point is these interventions really can be effective. Why they are effective is more of an intellectual exercise.
Not really "supporting papers". Just random papers on the subject, most non-supporting.
E.g. one of linked papers covers a research on "alternate day IF" and concludes: "Alternate-day fasting did not produce superior adherence, weight loss, weight maintenance, or cardioprotection vs daily calorie restriction."
Another is a meta-study that concludes: "Although both treatment interventions achieved similar changes in body weight (approximately 7 kg), the pooled estimate for studies that investigated the effect of intermittent energy restriction in comparison to continuous energy restriction revealed no significant difference in weight loss".
A third of the linked studies concludes: "Research has not demonstrated that alternate-day fasting regimens produce superior weight loss in comparison to standard, continuous calorie restriction weight-loss plans."
So it's just a random "blog" style post, on health.harvard.edu nonetheless, that gives several links, that do not support its thesis.
But a casual reader will think "hmm, the post says IF is good, and gives links to several studies, so the science is solid" (assuming that the links support IF).
I assume you mean low glycemic load. I don't think so. I think we should all focus primarily on eating the right number of calories, and the behaviors that get us to do that. If that is Keto, or IF, or Low GI, even something random like afternoon naps then great.
Also, for some populations, like athletes, a low-gi diet would end up resulting in decreased performance. I think it's really difficult to make sweeping dietary recommendations because there are just so many confounding factors.
I’m doing 18:6 or 20:4 protocols, I eat 2 meals per day usually and I like measurements. My blood ketones during my fasting are through the roof, over 1.5 mmol/L after 15 hours of fasting, which indicates deep nutritional ketosis and an indication that lypolisis is efficient.
I can tell you this would not happen if I ate 6 small meals per day. And I know because I measured myself. But it’s also how the body works ... ketosis happens after the liver’s glycogen stores are depleted, which takes 10-12 hours and the switch to burning fat isn’t very efficient and getting less so with age. Your body needs a break from food in order to mobilize the energy in your adipose tissue.
With 6 small meals what actually happens is constant hunger because you’re interrupting lipolysis every time you eat. This happens even with the ketogenic diet, because even meat triggers a hormonal response, small but not insignificant.
Also speaking from my own experience, I suffered from hunger at night, which made me binge. Switched to IF, hunger is now gone. Sounds like a paradox but it really isn’t.
The problem is that there isn't any real data, on an epidemiological level, that says this matters. I don't mean to be offensive, it's just a weird obsession with the Keto community I don't really understand. Same with insulin spikes. They just don't matter. It's averages over a long period of time that matter. If you're eating two large meals, you're still releasing a lot of insulin, you're still doing the same amount of fat storage, you're just timing it differently. If that works for you, great.
> I can tell you this would not happen if I ate 6 small meals per day. And I know because I measured myself. But it’s also how the body works ... ketosis happens after the liver’s glycogen stores are depleted, which takes 10-12 hours and the switch to burning fat isn’t very efficient and getting less so with age. Your body needs a break from food in order to mobilize the energy in your adipose tissue.
This is a semantic construction that is not supported by the science. You are correct that you would not measure nearly as high blood ketone levels, but you are incorrect in the idea that you wouldn't consume essentially the same amount of fat over the same amount of time given the same caloric inputs. Most people also go into ketosis while they are sleeping.
> With 6 small meals what actually happens is constant hunger because you’re interrupting lipolysis every time you eat.
This doesn't matter. Given the same energy requirements and the same energy inputs you're going to burn the same amount of fat over a 24 hour period regardless of when those inputs come. Anything else is an extraordinary claim that requires extraordinary evidence.
> This happens even with the ketogenic diet, because even meat triggers a hormonal response, small but not insignificant.
Yes, keto is actually a low protein diet as much as a high fat diet. Most people ignore the first part.
> Also speaking from my own experience, I suffered from hunger at night, which made me binge. Switched to IF, hunger is now gone. Sounds like a paradox but it really isn’t.
This is great, and a very real reason for people to try IF/Keto/Other diets. But it does not suggest anything other than a compliance hack that is working well for you.
Yes, but your body won't be able to use it's stored fat in the presence of insulin. If you keep that up long enough, you can only burn calories coming in. If you eat a lot of meals AND a caloric deficit your body needs to decrease your metabolism, mostly heat, thus cold hands and feet.
> This is a semantic construction that is not supported by the science.
It is. See insulin vs glucagon.
> but you are incorrect in the idea that you wouldn't consume essentially the same amount of fat over the same amount of time given the same caloric inputs
It's about your metabolism not CICO.
> Most people also go into ketosis while they are sleeping.
Well it won't be a deep ketosis. The longer your fast, the lower the insulin, the more body fat will be used.
> This doesn't matter. Given the same energy requirements and the same energy inputs you're going to burn the same amount of fat over a 24 hour period regardless of when those inputs come. Anything else is an extraordinary claim that requires extraordinary evidence.
It absolutely does matter, because your body does not burn a static amount of calories but adapts to the situation. Slowing metabolism is real. If you can't burn energy (low caloric input but frequent meals), your body will do what it needs to survive.
> Yes, keto is actually a low protein diet as much as a high fat diet. Most people ignore the first part.
Yes!
> This is great, and a very real reason for people to try IF/Keto/Other diets. But it does not suggest anything other than a compliance hack that is working well for you.
While it's anecdotal, there are good reasons for this effect.
You don't need to go low carb for a healthy diet, but cutting insulin raising foods for periods of time does have its merit. Take no more than 3 meals a day and leave 12+ hours food-free. Will do wonders for most people.
Right but what happens when you no longer inputting calories and thus no longer have high insulin? Then you start burning the fat again. You can only keep your insulin levels pathologically elevated if you are eating enough to support that over the long term, regardless of when you eat. Again, your body is very good at supplementing energy needs with fat when it needs to. Again there is no study showing meal time having any impact when calories are balanced, and several confirming the opposite.
> It absolutely does matter, because your body does not burn a static amount of calories but adapts to the situation. Slowing metabolism is real. If you can't burn energy (low caloric input but frequent meals), your body will do what it needs to survive.
Your body adapts to a short term situation (a meal and the small post-prandial period) but in the long term (24 hour period) it makes zero difference.
> Slowing metabolism is real.
Yes but it's also reversible by, shockingly, increasing caloric demand.
To be very clear, the proof required for what you are suggesting is a study with a minimum of 2 groups eating the same exact meals but at different times, and being forced to finish the entire meal and experiencing different outcomes. This has never happened, and based on our current understanding of metabolism never will. Maybe it would change, but this would be a massive massive change in our understanding of how the human body deals with energy.
Humans, difference in body composition: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645638/
https://ir.lib.uwo.ca/wurjhns/vol8/iss1/4/
Again difc in body composition in humans, but references to previous studies showing difference in mass in mice:
https://nature.berkeley.edu/garbelottoat/wp-content/uploads/...
> Humans, difference in body composition: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645638/
So this study is actually not bad. It has three small flaws that I can find, but is still compelling regardless. It is one of the only studies I have ever seen that did a decent job controlling the food. I'd like to see it repeated and at a larger scale, of course. The flaws are:
1. Malabsorption is a real issue when consuming nearly 2400 calories in a small window. This could be a real confounder with regards to metabolic differences. The malabsorption could be resulting in fewer calories being consumed.
2. Massive withdrawal rate in comparison to other dietary studies. The authors address this, I think reasonably, by concluding that IF is actually really difficult for a lot of people to comply to. This isn't necessarily a strike against IF being metabolically better, but if we dig into exactly why the diet is hard to comply to and force the people who didn't want to comply to comply, we might get different metabolic results. There is a large potential for survivorship bias here.
3. Sample size is tiny blah blah. This doesn't disregard the study but it does limit its applicability.
Good find, though, thanks!
As for the other two, I don't think they meet the requirements really.
No, diabetics have an elevated insulin levels for hours after a meal. Like, after 4 hours it's still at the level a non-diabetic peaks at after 0.5-1 hour. Eating many meals will keep your insulin levels high all-day.
> Again, your body is very good at supplementing energy needs with fat when it needs to. Again there is no study showing meal time having any impact when calories are balanced, and several confirming the opposite.
Your body is very bad at burning fat in the presence of insulin. Meal time is only important as to not keep your insulin level elevated all the time.
> Your body adapts to a short term situation (a meal and the small post-prandial period) but in the long term (24 hour period) it makes zero difference.
If you are eating all the time, the short term situation becomes the long term situation, not barely on 24 hour periods but for years on end. This is especially true for diabetics and pre-diabetics, as their insulin level will lower way slower.
This is not to say you can't avoid the whole situation by lowering your calories BEFORE you become diabetic. It may actually be the best way, but the science is far from being set because it's such a complex problem.
> Yes but it's also reversible by, shockingly, increasing caloric demand.
It's reversible by either supplementing more food or allowing your body to access its own resources (low insulin!). Increasing caloric demand (exercise!) will help insofar as you're burning of sugar -> less insulin.
> To be very clear, the proof required for what you are suggesting is a study with a minimum of 2 groups eating the same exact meals but at different times, and being forced to finish the entire meal and experiencing different outcomes.
While I'm not a fan of isocaloric studys, this should work, yes. You would also have to factor in a lot of other parameters, like established insulin resistance (probably using Kraft-Patterns)
> This has never happened, and based on our current understanding of metabolism never will. Maybe it would change, but this would be a massive massive change in our understanding of how the human body deals with energy.
I'm genuinely interested as to what your understanding of insulins / glucagons effect on your body's ability to access fat is.
I have repeatedly said in this thread this doesn't apply to diabetics, who do have an insulin pathology. Diabetics do need to worry about insulin, non-diabetics do not.
> Your body is very bad at burning fat in the presence of insulin. Meal time is only important as to not keep your insulin level elevated all the time.
There is no science that disambiguates between large spikes followed by zero food in take (IF), and small spikes continually at the same calorie levels. Please feel free to send any study you think does.
> It's reversible by either supplementing more food
Again this is only relevant to the post-prandial window. If you are overweight, and have a slow metabolism, and respond by eating a lot of food, you will not successfully "speed up" your metabolism outside of the prandial window. If you are overweight and start dieting, your metabolism with slow down, but the evidence overwhelmingly shows exercise counteracts this, and that the slowdown is reversible when your body fat percentage lowers.
> If you are eating all the time, the short term situation becomes the long term situation, not barely on 24 hour periods but for years on end. This is especially true for diabetics and pre-diabetics, as their insulin level will lower way slower.
No, this is only true if you are eating all the time and also eating too many calories. . Again, please send a link to a study you think says otherwise.
> While I'm not a fan of isocaloric studys, this should work, yes.
Why are you not a fan of the only kind of study that could possibly prove your point? And why hasn't this study ever been successfully completed? Why have studies that attempted to do this been unable to show any difference in outcomes?
> I'm genuinely interested as to what your understanding of insulins / glucagons effect on your body's ability to access fat is.
I don't really know what you're implying here, but I suspect you are still getting hamstrung by the prandial window. Yes, insulin can block your ability to access fat in the short term, no it will not in the long term, and it does not do so entirely either. If you are eating the same number of calories and thus constantly releasing insulin you are blocking some, but not all, lipolysis. Lipolysis is not a binary, nor is insulin release. You can have both of them happening at the same time, even though insulin is blocking some of the lipolysis.
Point taken :-)
> There is no science that disambiguates between large spikes followed by zero food in take (IF), and small spikes continually at the same calorie levels. Please feel free to send any study you think does.
and
> No, this is only true if you are eating all the time and also eating too many calories. . Again, please send a link to a study you think says otherwise.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4079942/
> Why are you not a fan of the only kind of study that could possibly prove your point?
Because you're on a circadian clock with lots of hormonal regulations that have huge influence on you. Most people won't feel as hungry on a fat-heavy diet as on a low-calorie (mostly low-fat) diet. Long-term adherence to low-calorie diets is just not working out for most people. Yes, calorie-restriction works in basically every living thing to prolong life. No, people will not do it.
> And why hasn't this study ever been successfully completed? Why have studies that attempted to do this been unable to show any difference in outcomes?
There is evidence. Please don't tell me there is conclusive evidence on anything related to nutrition. The second statement is not true, differences have been shown.
> I don't really know what you're implying here, but I suspect you are still getting hamstrung by the prandial window. Yes, insulin can block your ability to access fat in the short term, no it will not in the long term, and it does not do so entirely either. If you are eating the same number of calories and thus constantly releasing insulin you are blocking some, but not all, lipolysis. Lipolysis is not a binary, nor is insulin release. You can have both of them happening at the same time, even though insulin is blocking some of the lipolysis.
Yes, it's not binary, but the easy way to increase lipolysis is to decrease insulin.
Right, this is the point: it's about compliance, which is real and important, but very different from metabolic change.
> Please don't tell me there is conclusive evidence on anything related to nutrition. The second statement is not true, differences have been shown.
No, there is no study showing the same number of calories consumed over different feeding schedules have any different outcomes. I am 100% confident about this. To be clear: there are studies showing people on IF eat fewer calories, and that eating few calories has net benefits. That's great, but that's compliance not metabolism.
> Yes, it's not binary, but the easy way to increase lipolysis is to decrease insulin.
Again, time windows. Please consider time windows. In a 24 hour period this stuff is all neutralized. Or maybe it's not, but we don't have any science showing it's not, and quite a bit showing it is.
But...
My own experimentation (beware of experiments with the sample size of one...) results is that restricting myself eating rarely but in bigger doses makes me feel more healthy and makes keeping / loosing weight much easier. Rarely in this case means something like one large meal a day or every two days or something inbetween.
Now, I attribute this to what happens between the meals.
Just as training to run a marathon is mostly focused on teaching your body to reach into fat stores before your glycogen stores run out I think of fasting in between meals as an excercise for the body in running pathways in the opposite direction.
My understanding is that the fat stores are neither good or bad. Your body uses them to store energy for later with the assumption that it will be extracted at some point.
If you keep yourself satied constantly, keep insulin levels all the time except maybe short time before breakfast, your body is not trained in effectively using the stores. The metabolic pathways for ketosis are unused and underdeveloped.
In that state, as soon as you stop eating and blood glucose levels fall you start feeling hungry. There are other reasons for this happening (misinterpreting not being satiated for hunger) but one of the reasons is that the metabolic pathways for getting back at your fat energy stores are not kicking fast enough to react to demand.
This is of course vicious cycle -- you get hungry quickly so you reach for a snack or something else to immediately satisfy your hunger which further makes sure you never excercise yourself to deal with hunger.
Interestingly context can totally reverse the implications here too. For instance: as a weightlifter I want a heavy insulin response and I want a heavy inflammatory response because both of those help build muscle. So even saying that inflammation is bad requires a bit more nuance. It's very complicated, which is why Calories In Calories Out is such a powerful simplification. It doesn't tell you everything, but everything fits into that explanation, and if you can figure out how to control calories a ton of other bad things stop happening too.
It sounds like your conclusion is roughly that, sufficient nutrients aside, it doesn’t make a damn bit of difference which columns the calories are under, not just in terms of weight management, but general health.
Yet, I struggle to entertain the possibility that the guy eating a lot of pizza and ice cream and candy is going to encounter health problems a lot sooner than someone of the same CICO eating avocados and chicken and broccoli.
Is one just as good as the other? What about skinny people who get heart attacks?
My conclusion is that but slightly more conservative: more that science is really hard, and we have not been able to show that macro nutrient composition matters nearly as much as we thought. It may still matter quite a bit, though you'd expect it to be easier to measure if it did, but again science is hard.
> Yet, I struggle to entertain the possibility that the guy eating a lot of pizza and ice cream and candy is going to encounter health problems a lot sooner than someone of the same CICO eating avocados and chicken and broccoli.
I can show you small scale examples of people doing this and not having problems (http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/...) but I can't show you a strong epidemiological study that confirms this, unfortunately.
> What about skinny people who get heart attacks?
This does happen, though of course far more rarely. Lots of stuff impacts this (genetics etc.), and I don't know nearly enough about heart attacks to comment, but I will say broadly that one of the worst things you can do for your heart, and most of the rest of your body, is to be fat, and the only way to be fat is to eat excess calories.
Given my current understanding from all the intermittent fasting hype lately, it is indeed better to eat big meals rarely rather than small meals frequently. For some reason, your post got me slightly confused because I lack the necessary knowledge to have a proper model about nutrition in place.