I think this is what people are missing. The laws of thermodynamics are not being violated with these various diets, and like you mentioned, for certain individuals their metabolism is being increased.

This suggests something tech could actually help with.

Since each person has a different gut microfauna, if we had a system to measure my gut and compute what foods would be good for me, we could design custom diets for each person.

I agree with you to an extent. However, none of this changes the fact that consistent exercise increases the rate of metabolism significantly and generally leads to better mental and physical health. It also doesn't change the fact that eating at a caloric deficit will always lead to weight loss. A caloric deficit alone is not enough for one to reduce to a healthy weight as they may also be losing large amounts of muscle mass. Conclusion: Consistent exercise and a well-balanced diet are still the best ways to become healthy and maintain health.

But it's not that simple -- "eating at a caloric deficit" isn't a constant thing. You can eat less, but your metabolism might drop even further, so eating less calories can lead to weight gain, or a loss of muscle mass that is more than made up for by a gain in fat. And plenty of research shows that exercise is, for most people, counterproductive for weight loss because they wind up eating afterwards than the calories they burn. Yes, exercise leads to general better health, but that's a very different goal from losing weight.

>"eating at a caloric deficit" isn't a constant thing. You can eat less, but your metabolism might drop even further

This exactly why I mentioned consistent exercise. Exercise will speed up your metabolism as it causes the breakdown of muscle mass and other tissues which then need to be repaired and improved by your body. You can push exercise even further by buying into linear progression and training your body to rebuild itself in order to adapt to your training regimen.

>research shows that exercise is, for most people, counterproductive for weight loss because they wind up eating afterwards than the calories they burn

This is not an argument against my position. This is caused by a lack of discipline. Also, eating after exercise can be a good thing. The effects of a heavy weight lifting session will linger for several days and burn far more calories than the actual session itself. The muscle that was damaged during the training session needs high quality nutrients to be rebuilt. I, for one, usually eat a philly cheese steak or hamburger if I have a really intense training session because I know I need the fat and protein. People seem to think that exercise is a means to burn calories. It is not. Exercise is a means to an end. For some people, it's strength, for others it may be rock climbing. For others still, it may be for general health.

>Yes, exercise leads to general better health, but that's a very different goal from losing weight

My argument is that losing weight is a means to becoming healthy. You cannot become healthy without a well balanced diet AND consistent exercise. If your goal is simply to lose weight, exercise will aid you in that endeavor AS LONG AS your diet is in order.

Becoming healthy is not a diet. It's not going to the gym once a week. Becoming healthy is a lifestyle choice and not everyone has the foresight and discipline to do it. If someone doesn't have that discipline and self control, that's fine. Just done blame it on genetic issues or confusion. Say it like it is, you're(general you) just lazy. And that's OK.

Oh no, not the "starvation effect" nonsense again. That's been thoroughly debunked.

No, it hasn't, which is why yoyo dieting is so harmful and why refeeding people with anorexia is done so carefully.

Anorexia treatment has zero relevance to the vast majority of overweight people who need to eat much less to lose weight.