[corry]

Does anyone remember a meta study that showed ANY even slightly reasonable restrictive diet works because they almost by definition dramatically reduced sugar and HFCS in the diet, and if you just controlled for that, the individual types of restriction didn't matter?

I can't find it on PubMed or in my bookmarks.

If memory serves - high/low fat, high/low carb, high/low protein, etc - didn't matter as long as the restriction is stopping sugar/HFCS.

And it also explained the rebound effect - e.g. after the extreme restriction, the participants start re-introducing sugar and HFCS back into the diet, and since that's the real culprit, weight goes back up.

No taking away from this super cool citizen science - deep kudos on testing things like this out! I'm tempted to participate in something like this. Self-experimentation is a lost art.

[pr0zac]

The thing that fully convinced me over a decade ago that all effective methods for weight loss are just "calories in, calories out" underneath was the dude that lost 27lbs in 2 and a half months on a diet of mostly twinkies with occasional other junk food for variety. https://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor...

Yes, there are other variables like hormone levels (thyroid adjacent ones particularly), genetics (defines base metabolic rate), drugs/chemicals (some effect metabolism), and dietary macros (too much sugar causing diabetes) which factor in to weight loss or gain, but its pretty clear at the end of the day all they are doing is modifying the numbers each individual needs to use in the same old calorie calculations, and very often not to a high degree.

I get its fun to play with theories and edge cases, but I don't understand why so many people find this simple, well established explanation unsatisfying and hard to accept.

[bscphil]

> I don't understand why so many people find this simple, well established explanation unsatisfying and hard to accept.

Because when people try to put it into practice in a form that's not dangerous they struggle, and when humans struggle at something they feel compelled to theorize the struggle. "There must be a reason this isn't working for me," they say, "one that doesn't ultimately reflect on my morally culpable lack of capacity to exert my will." [To be clear, I don't think people are to blame for lacking willpower, I'm just identifying the logic here.]

Looking around, they observe that some people have more success on a diet where they restrict some particular type of food X. This success comes from playing a trick on the brain, making it think that it is not in a position of deciding to eat less every day, but is being forced to eat less. Some restrictions manage to play this trick on the brain successfully for some people some of the time. People promoting diets that are not just "calories in, calories out" are hoping to take advantage of this effect. When these diets become popular, it's because the logic I identified allows people to say "it's not that I failed to force myself to eat less, it's that I didn't stop eating carbs" - or what have you.

One reason it's hard to eat less that you didn't bring up is that the body reacts to you eating less by reducing your metabolism. I don't mean this in a magical fashion where the body has a high efficiency mode or that you can somehow gain weight while eating fewer calories than you consume, but in the simple ordinary sense that people dieting tend to be tired and more lazy. Your body does not want to stay at the same level of activity while dieting, and so you lose less weight than you'd expect with a simple metabolic rate calculation. You can allow for this of course, but it means you have to cut even more.

So I don't know that many people reject the basic physics of calories in, calories out per se. Most reasonable people talking about this are more interested in why attempting a pure "eat less food" diet tends to fail, and what tricks can be employed to achieve appetite reduction. The various individualized factors can be overwhelming, especially when you consider that many people don't have access to adequate nutrition and healthcare.

[ForkMeOnTinder]

It's the calories. People have lost weight by eating nothing but McDonalds (and strictly counting the calories of course)

[derbOac]

Yes, there was at least one meta-analysis several years ago that compared different diets to each each other and to exercise. I think there were actually two meta-analyses that came out about the same time, with slightly different foci, and came to similar conclusions.

What I remember was that diets didn't differ from one another in efficacy once you controlled for caloric restriction, and that dieting was more effective than exercise, although exercise did have a small but quantifiable effect.

I also think one of the meta-analyses compared atkins-style diets to others and concluded that there was some slight evidence for their superiority (in terms of weight loss) in the short term but that after a few weeks they didn't differ from the others.

I've worked in bariatric surgery units and my personal sense from that and reading some of the literature is that a lot of what works best is highly individual-specific due to all sorts of reasons, including personal food preferences, genetics, microbiome, etc etc etc. The standard explanation for diet working better than exercise is that the extra caloric expenditure of exercise gets washed out by excess intake; I think this is undoubtedly true but after having worked clinically in obesity settings, I also think it's really astonishing how little exercise some people get. That is, again, I think some people who start adding a modicum of exercise are likely to see huge gains from it simply because their caloric expenditure is starting so low; conversely, most people who take up exercise probably exercise within a certain range, so it doesn't say a lot about the expectable weight loss of someone who is really exercising intensely.

[tekla]

They work by definition because you eat less calories