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Is alternate-day fasting superior to calorie restriction in lean adults? (peterattiamd.com) similar stories update story
2 points by prostoalex | karma 125988 | avg karma 10.16 2021-10-11 10:13:45 | hide | past | favorite | 70 comments



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Tl;dr no it’s not, calorie restriction wins in terms of fat loss. Very interesting article!

let's solve this once and for all:

1. try to eat healthy, mostly-natural foods (and you know what is healthy and what isn't)

2. don't eat too much

3. exercise every day. sweat is a good indication

it's not THAT hard folks, go look at pics from the 1910s, obesity was almost nonexistant

also:

1. there is no way to be in shape while eating crappy food all the time

2. there is no way to be in shape and never exercise at all


> there is no way to be in shape while eating crappy food all the time

While I agree with most of what you said, that point is false.

The obscene Michael Phelps five hour swimming diet included, among the 10k-12k daily carb heavy calories, such things as:

"Three slices of sugar coated French toast."

"Three chocolate-chip pancakes."

"Half a kg of pasta."

"Two large ham and cheese sandwiches with mayonnaise on white bread"

"Energy drinks that supplied him with another 1,000 calories." (which means they were sugar heavy)

"Half a kg of pasta"

"An entire pizza"

The reason he could be in such amazing shape while eating that garbage, is because he was burning it off with the five hours of daily swimming.

https://www.aspirechannelswim.co.uk/blog/michael-phelps-12-0...


Damn, I want this guy's diet. Also, his olympic swimming performance.

I'll start with the diet


do you really need me to say "you're not Michael Phelps"??

this no different than ultrarunner Dean Karnazes who would eat an entire pizza...but he also was doing so while running 100 miles in one shot

you are not these people


Why not simplify it even more, and add:

4. Be born with genetics that avoid this common issue

Also, obesity used to be a status symbol, as a proxy for power, in many cultures. It wasn’t impossible before 1910, just likely more difficult to attain. And it seems unlikely that people in 1910 and before ate particularly “healthy,” as we define the term in 2010, since the modern abilities to produce and distribute food weren’t yet available. So perhaps remove point 1, if we want to be historically accurate?


> It wasn’t impossible before 1910, just likely more difficult to attain.

Find that hard to believe. It's not like there were meaningful economic restrictions from eating enough calories to get fat prior to 1910.

More likely, people were just more active and food was less addictive.


> exercise every day. sweat is a good indication

No it isn't. It's very person and weather dependent.


very well summed up, my version:

- eat for max nutritional value (as you say, we KNOW what this means - natural foods, preferably "wild" or as close to wild as possible)

  I understand most of us can't eat like hunter-gatherers anymore, what I mean is prioritize quality, don't eat heavily industrialized nutrient-poor foods
- eat a macronutrient ratio leaning towards more natural fats (no industrial seed oils), minimal carbohydrates (occasional fruit but not the common excessively sweet kind), get enough protein for your activity level

- exercise focusing on generating heat/sweat


> there is no way to be in shape and never exercise at all

Outside of physical jobs, I don't think people were exercising all that much in the 1910s. Working out for everyone seem like a recent thing.


walking five miles to work

> there is no way to be in shape while eating crappy food all the time

Even the great arnold says in his interviews that he was mostly eating burgers while training for mr olymptia


A shame they didn't look at IF+CR and IF-only groups. In my circles IF is much more common than something like ADF, but, that could be noise.

>Another factor to consider is that this was a study in “lean” adults, and it is possible that results would be different if the investigators included people who actually need to lose weight.

This just kind of reads like "which of these diets leads to healthy individuals becoming even more healthy", and the answer was none of them. There's got to be diminishing returns on healthy practices.


Once again, the only diets that work, work because you take in fewer calories than you burn.

Calorie counting restricts calories (obviously).

Fasting restricts calories (and hopefully enough to lose weight).

Keto often ends up lowering calorie intake, because you feel more full on fewer calories.

Exercise burns calories, helping contribute to weight loss (or at minimum, slowing weight gain, all things the same).

etc. etc.

There's no magic in Keto or IF. It's mostly just calories in, calories out. Anything else that it's doing is minimal enough to not worry about it.

The only thing that matters is finding something that works for you. If that's Keto, great. If that's IF, great. If that's just old-fashioned calorie counting, great.


Some foods affect appetite differently than others. This can lead to decreased calorie intake without increased effort/suffering.

I object. Avoiding pasta is suffering :)

Calorie counting or IF works better for me (I've done both). Let's me eat anything I want, just less of it.


I have the opposite experience.

Eating high carb / junk food triggers cravings and overeating.

Eating protein, greens, etc... Makes eating the correct amount of calories much easier, as I actually feel full.

That said, my sister has the same experience as you. She can lose weight eating Pizza, as long as it's the correct amount of Pizza.


I lost weight eating cake, absolutely delicious, I always felt full, and had plenty of energy. High protein diets made me feel miserable.

Yep, if you rely on exploiting your physiology and eating totally different foods to lose weight and maintain then it's going to be a struggle if you ever want to go back to normal.

> "It's mostly just calories in, calories out."

Is it? Not all calories are burnt equally by the human body, right? It seems that you are just trying to simplify something that it is easy to understand rather than scientifically sound.


They are. Every calorie, if burnt, is burnt equally by the human body.

Now, whether they are burned or passed is another story.

But your body will never store a calorie when it needs to burn and it will never burn when it should store.

Every calorie ingested needs to be accounted for, either through work, waste, or storage.


This model requires a much more rigorous definition around the words "should" and "needs".

> Every calorie ingested needs to be accounted for, either through work, waste, or storage.

What people are arguing on here is that, depending on the type of food - for a given amount of work - will the remaining calories be converted to storage or waste ?

You can loose weight with a higher calories intake, even if your work stays the same, as long as your waste grows comparatively higher.

And their point is that, in that sense, there is a difference according to the type of food and the individual. Finding an efficient weight loss diet means finding a type of food that you enjoy eating, and gives a high satiety feeling and has a low storage/waste ratio. It's not always easy.


> You can loose weight with a higher calories intake, even if your work stays the same, as long as your waste grows comparatively higher.

This is what is typically known as bulimia.

There is some difference, but not enough to matter. That's the point. You aren't a "lion", "bear", "lizard" or whatever animal. You aren't an "endomorph" or "ectomorph". Your metabolism isn't that much better or worse than anyone else's.

Watch your intake and everything else falls into place.


It's not. That idea is obsolete and is very easy to prove.

Take patient A in a control room and make him eat 2000K calories a day. Take patient B into the exact same environment, eating the same calories.

Apply insulin shots only to patient B

Patient B will get fat, and patient A won't, eating the exact same calories.


That's great if we all live in control rooms. The part 'calories in calories out' misses is that what you eat, how you eat, where you eat, how your body reacts to what you eat, who you eat with, where you live, what food is available, the price of food....all impacts how much you eat.

I think of 'calories out' as including all the the what, how, where, etc. I think 'calories in calories out' is true, but I think often only things like exercise and BMR are considered in the sum of the out.

The part that it gets right, though, is that way too many people are lying to themselves about how many calories they are actually consuming. It's not like the average overweight-obese person is sitting at 2000 calories a day and can't figure out why they aren't losing weight. They're eating 1000 calories a meal, drinking soda, eating snacks.

Sure there are metabolic outliers and everyone loves to bring them up. They are, however, outliers. Horrible diet and a sedentary lifestyle are the main culprits where calories in/out very much holds.


I don't see this is a contradiction when you chemically alter someone's calories out by messing with their metabolism.

But sure, we can rephrase CICO in a way that's more precise. For any person with a given diet there exists a caloric intake where they will lose weight. Or as a one liner: "if you're not losing weight, you can always eat less until you do."


That's not what the OP is suggesting, though. "calories in, calories out" does not mean that my 2,000 calories is the same as someone else's 2,000 calories. It means that if I am gaining weight eating 2,000 calories a day, I will eventually lose weight if I eat fewer and few calories. (ie, I may not lose weight at 1,900 calories per day, but I would absolutely lose weight at 500 calories per day.)

BMR might drop around 10% when doing traditional calorie restricting dieting. Some diets try to prevent that the best they can (keto, for example).

If a specific diet was able to mitigate the drop in BMR (unlikely to completely mitigate if you're losing weight), then it might be the difference between like 2000 calories burned a day and 2150 burned in a day, right?

Is that optimization worth considering? I don't think so. People should focus on a diet that they can stick to, not something that optimizes that much.


A "calories in vs calories out" mindset makes the (incorrect) assumption that for a given unit of food, all persons will absorb the exact same quantity of calories from it. Our digestive systems do not extract 10% of available energy from all consumed food, and the amount we do extract varies based on a number of different factors including microbiome, expression of certain hormones (e.g. insulin), etc.

The "magic" that people refer to with keto, etc is that some things can have effects that cause our bodies to absorb less of the calories that were put into our mouths.

This is one of many reasons why some people lose weight more readily than others given identical diets and exercise regimens.


Thanks for mentioning this effect; I sadly seem to primarily have friends in the 'can't gain weight no matter what they eat'-group, and if I try to keep up with their eating-habits, I gain two pounds a week.

And yes, I do exercise a fair amount and all that, but I also seem to be quite efficient at extracting energy from food. I tend to joke that at least I'll survive longer after the apocalypse.


Unless your friends have tape-worms, are suffering from untreated Celiac disease, or the like, [1] I doubt you're significantly more efficient at absorbing food energy than they are. It's a myth that people get overweight from being better than others at extracting energy from food. In a peer comment to yours, I gave a citation to that effect.

I think basal metabolic rate can vary significantly. This might explain what you're observing in a more biologically plausible way. My (imperfect) understanding is that it's partly genetics and partly in your control via strength training.

But I think you're doing yourself a disservice if you're discounting too easily the possibility that you're not comparing your eating and exercise with theirs accurately. How confident are you that you're actually eating no more calories than they are in a typical week? You might see them eat a huge amount when you're together, but maybe that's their "cheat" day, maybe they don't snack or drink alcohol as much as you do, etc. I think a lot of people are fooling themselves when comparing to others.

[1] not a recommended weight loss plan; side effects can include stress fractures, scurvy, IBS, and on and on.


> Our digestive systems do not extract 10% of available energy from all consumed food, and the amount we do extract varies based on a number of different factors including microbiome, expression of certain hormones (e.g. insulin), etc.

Do you have a citation for this? Here's one saying almost the opposite:

> Carbohydrates, protein, fats, and alcohol—the dietary macrocomponents—are the sources of energy in the diet. Under normal circumstances, more than 95% of this food energy is digested and absorbed from the gastrointestinal tract to provide the body's energy needs. Studies of normal and overweight subjects have not shown any significant differences in the proportion of food energy absorbed. In some underweight subjects, however, malabsorption of nutrients is an important factor.

https://www.ncbi.nlm.nih.gov/books/NBK218769/


People doing CICO don't assume that all which is why "your number" where you lose weight varies person to person, diet to diet, and changes over time. CICO just says that a number exists where you'll lose weight.

W/E marginal differences exist outside of specific health conditions they are less than negligible.

People do extract pretty much the same amount of effective calories form identical foods, it’s basic evolution as more efficient eaters would’ve outcompeted the rest a long time ago.

So unless you have celiacs, an onset of diabetes or some belly buddies you aren’t going to be absorbing less calories than someone else.


I don't know if it's true or not, but there is the thought that KETO also works by increasing the calories out.

Because the body uses glucose for fuel, if you only give it Fat and Protein, those calories must be converted to glucose before they can be used, resulting in a higher caloric burn than you would normally see.


There is some magic to keto though. It puts your body in a mode that explicitly burns fat for energy. As well, calories in calories out has an implication that all foods as equal. If you eat sugar directly in normally sold quantities, it's probably getting stored as fat [1], unless you're on a soda fast or something.

https://healthcare.utah.edu/the-scope/shows.php?shows=0_7frg...


The calorie-in/calorie-out model is most likely (almost certainly) not so overpoweringly important that all other aspects of dieting are minimized to the point that they are negligible.

That would mean the interaction of food choices and the hormonal system would be negligible, that the interaction between foods and the microbiome would be negligible, and the presence or lack of micronutrients is negligible.

Calorie count is definitely important, but to claim that any other components of the diet (food choice, timing, etc) are negligible is an incredibly strong claim with evidence building against it as metabolism is more thoroughly explored


I'd say it's an incredibly strong claim that they aren't negligible.

Most research I'm finding says that your BMR may drop by like 10% with a classic calorie restricted diet (which itself accounts for about 75% of total calories burned in a day).

So what are we talking here at most? 150-200 calories a day if a diet is able to completely stop a decrease in BMR as you lose weight? Less if it's not?

What's the line that makes it worth it? A 100 calorie per day optimization is not worth it to me when I have to drop 500-1000 a day to have any real weight loss.


I think the "calories in, calories out" argument isn't so much wrong as it is tautological. It's the equivalent of saying the key to winning in sports is scoring more points than your opponent. It not only answers none of the interesting questions about weight and diet, it implies those questions don't exist.

It also ignores the role of macronutrients and digestive absorption rates entirely.

For example, one could drink one cup of olive oil daily and get ~2000 calories into your body. You would probably start suffering immediately on that type of "diet" because 1. your body isn't going to run on pure fat forever, and 2. your digestive system isn't going to process that amount of olive oil effectively.

Therefore it's not helpful to just say "Calories in, calories out" without actually looking at what you're eating.


No one is drinking a cup of olive oil daily (hopefully), so why use that as an example?

What level of optimization are you getting by looking at macro nutrients and digestive absorption rates? More than 100 calories per day? I don't think it's worth the effort.

I think a big problem is that whenever dieting is brought up, people throw out the basics and try to be fancy, talking about insulin and macro nutrients and fat burning and digestive absorption rates. Why? It's unnecessary to complicate it that much and turns people away.

Then you have people starting Keto and being confused why they aren't losing weight, because they were told that ketosis is more important than keeping track of how many calories you're eating.


Complexity of the food source is key. The same amount of calories in sugar, olive oil, meat or chickpeas result in completely different absorption rates in the gut. While sugar will be immediately dumped to the blood stream, chickpeas will take hours to digest until all the sugars become accessible. The body needs to expend calories to access the calories in food high in fiber. Don’t forget about the varying responses of your gut microbiome to different foods. Some calories are easier to access for your body, because your gut microbiome has been inherited/adapted to them since early childhood. Some foods trigger a strong sugar spike in one person, while it does nothing in the next.

It’s way more complex than the simple equation of calories in = calories out.


You didn't answer my question. When it comes to weight loss, how much does it matter? Is it on the order of 100 calories a day? 300? 500?

It may be complex, but if you're only changing the calories burned by 100 calories a day, then it hardly changes anything. At some point it matters, and at some point it doesn't.


I actually don't disagree with your overall point when we're talking specifically about losing weight. For losing weight, it's all about limiting your consumption of calories from any source while increasing the amount of calories you burn daily.

Similarly, when I'm bulking to gain muscle mass I just eat more calories than I usually feel comfortable eating. However that doesn't mean eating a ton of chips or soda or "empty" calories from alcohol, it means tons of actual food, whether it be chicken or pad thai or chocolate milk. IMO, it's much more important to be watching what you're eating when you're putting on weight.

Personally I don't like the idea of keto because it seems really hard on your liver and kidneys, and that doesn't seem worth it at all from a health tradeoff perspective.


It's an extremely simple idea, but not quite a tautology. It's a necessary idea for debunking the worst of the fad diets. The second-order effects you allude to as the "interesting questions" are helpful for understanding things like how one diet can be easier to adhere to than another, or why the calorie counts on nutrition labels aren't 100% accurate in all circumstances, but the basic calories in/calories out idea still explains weight gain vs loss in a quantitative way.

Another way to see how useless "calories in, calories out" is, is to consider the advice "grams in, grams out". The law of conservation of mass is as valid as the conservation of energy, so, why calories and not grams?

This is how metabolic tests work. When you burn fat, it has a lot of carbon in it, speaking generally, after that fat is metabolized, that carbon binds with oxygen and is breathed out as C02.

So you can (and people do) use grams in/grams out to determine metabolic weight, but short of a lot of very specialized equipment, it's much easier for someone to have a rough measure of calorie burn at rest by choosing a standard value (or measuring it by the aforementioned metabolic test), and then approximating the amount of calories going in.

The psychology/physiology of weight loss is a complicated subject, but the thermodynamics isn't. It's very easy to just say "diet", but the hard part is the motivation, so while everyone is absolutely correct that counting calories is the "optimal" method of weight loss, it's not the strategy that optimizes results across the population.


> so while everyone is absolutely correct that counting calories is the "optimal" method of weight loss, it's not the strategy that optimizes results across the population.

More accurately: a calorie deficit is not "optimal" for weight loss so much as it is a necessary and sufficient condition for achieving weight loss. The problems are that accurate calorie accounting is harder than merely reading nutrition labels, and calorie counting on its own does not provide guidance on which foods to reduce or replace in your diet to achieve weight loss while staying otherwise healthy and sated.


Bad comparison, there are sports which a lower score is better. But, to stick with your analogy, "how do I lose weight?" is as generic a question as "how do I win?", "how do I win?" also glosses over all the rules and stipulations

No, calorie restriction by itself will not work.

If you lost weight you have burned more calories than you consumed. The other way unfortunately does not work.

Sometimes you restrict calorie intake, you feel ill, your body adapts and starts burning less with other repercussions.

If you want to lose fat you must restrict calories but also provide enough time for your body to use the stored fat, and it can not be used while the insulin levels are high. This is the reason that both IF and keto “work” (if calories are also somewhat restricted).

Ofcourse if you eat 1 meal a day it is more likely that you will consume less calories tahn eating 5 times a day (IF), also if you do keto you will not eat sugars (or other carbs) and again it is very likely this will lead to consuming less calories than otherwise.


A normal, safe level of calorie restriction in the range of 500 kcal/day will not cause your body to burn significantly less. However as you lose weight your resting metabolic rate will decline just because you have less tissue to keep alive and that takes less energy.

"the only diets that work, work because you take in fewer calories than you burn."

Yes, but how many calories do you burn?

It's determined by your metabolism, which is influenced by what you eat. It's not a simple equation.

And, how many calories do you "take in" when consuming a unit of food? As another poster pointed out it depends on the unique characteristics of your body. Also influenced by what you eat.


So, if i'm reading right, CICO still works, its just relevant to the user? Pretty sure that's what parent said

It works but both CI and CO are affected by what you eat, so it’s an uninteresting factoid. It’s usually used to tell people they need to eat less and move more to the exclusion of food choice which hasn’t been very successful in long term studies.

Which is not the end all be all for diet advice, but it generally works, and at minimum points people in the right direction. Of course there are edge cases, and other important factors. Consume less and move more is what most people need to do.

Sure, but not to the exclusion of heating different things. Which I understand to be the point of the CICO hypothesis, that the type of food doesn't matter if you only care about weight loss. See the Twinkie diet for example.

It would be nice to list a source. If you start an argument with "once again" it sounds more like you are fitting your theory on top of the new data point, rather than using the new data point to support a theory.

Calories in, calories out is disingenuous when talking about anything but a literal mechanical machine / vegetative state patient you feed fuel into or not.

The PRIMARY in human diets to adjust weight is psychological including both degrees of willpower and degrees of not needing willpower due to the feeling of satiety. Pretending "you could have just accomplished exactly the same thing by cutting calories" ignores completely the implied second half of that formulation: infinite willpower and endurance in the face of discomfort. People have to work and earn livings and lead lives, they cannot persist indefinitely in ego depletion.

It's about as ridiculous as saying anyone with the requisite genetics can be a world class body builder, if they just "worked out". Yeah. No, they can't, because there is a helluva lot more to it.


Most IF regimes come with the added instruction to eat more protein and less carbs to stave off sugar crashing, and that is whole weight loss strategy alone.

People that have never fasted before seem to think it is the hardest thing anyone could ever do. However once you've done it a couple times, you realize it's not a big deal at all, and sometimes you will even want to fast just for fun.

I like to fast for other benefit in terms of time, money, cleanliness -- not just for fat loss. Seems odd to run a study on lean adults and compare fat loss numbers as a goal. If they're lean, why optimize for fat loss?

Only 3 weeks, only 36 people, mixing men and women, all already lean. I don’t think any result here is relevant to any generalized conclusion, only to inform further research.

Losing a few pounds over a few weeks is easy, particularly if somebody is controlling how much food you take. The problem is what happens after, when you are under free living conditions: will you be able to maintain that weight loss, or will you grow increasingly hungry, tired and cold until you start eating again? We have all lost weight only to regain it after a year.

For that reason I'm most interested in interventions that work under free living conditions (ad libitum) and in the long run (2+ years), at least anecdotally.


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