[beatgammit]

I imagine very few people stick to a diet for 5 years, partly because they're not fun, and partly because many are unhealthy when done long term. Also, many health professionals recommended a max of 500 calorie deficit, which would mean ~50 pounds of weight loss in a year.

When would you need to follow a diet for 5 years if most people can reach their goal weight in 1-2 years? Once people reach their goal weight, they'll transition off to something else, which usually isn't a specific diet, but "eat more veggies" or whatever.

Given that long term diets are quite niche, I think limiting the study to 1 year makes a lot of sense.

[Retric]

Fat burns calories.

Generally, to maintain X pounds of weight loss you must consume ~10X fewer calories every day. In order to more quickly reach a new weight most people exceed that difference, but they can’t go back to old eating habits without regaining their original weight.

PS: Metabolism and exercise have real impact, but you can easily out eat any reasonable exercise plan.

[masonic]

  Fat burns calories.

Only brown fat (BAT) does, and humans have very little.

[Retric]

All cells require energy to survive.

On top of that strapping an extra 10+ pounds to your body and walking around would require extra energy for the same movements.