[freyr]

> I've yet to see anyone eat well and exercise and not maintain a healthy weight. Ever. Not once.

I too had never, ever met an overweight person who ate well and exercised. Not even once! Until I did meet one. Your anecdotal absence of proof is not proof of absence. The vast majority of overweight people may eat poorly and not exercise, but that doesn't exclude other possibilities.

In my case, I eat junk food and lead a sedentary lifestyle, and yet I'm lean and muscular. Care to explain?

[chez17]

Look at my original comment. Clearly there will be people who can get away with doing little and maintain weight while others will have to work much harder. I would guess you're pretty young as well, most young people stay relatively fit without doing much.

[paulhauggis]

This may be the case, but it's the exception to the rule and shouldn't be used by every person overweight who just give up on discipline because they think it's useless.

[zentropia]

The hypothesis is that the bacteria in your gut are able to affect your hunger. If you have this bacteria you are always hungry and eat the wrong kind of food.

[bashinator]

You met a person who burned more calories than they consumed, and yet didn't lose weight?

[freyr]

> You met a person who burned more calories than they consumed, and yet didn't lose weight?

No, as I said, I met an overweight person who consistently ate well and exercised (a college roommate). I have no idea how many calories they burned.

By comparison, I ate much more and exercised much less and had very low body fat. Again, I have no idea how many calories I burned.

And that's exactly point. That is to say, given the tremendous variation in almost every aspect of human physiology, is it plausible that there exist outliers whose bodies burn calories at markedly different rates? I don't know, but without more evidence, I'm hesitant to declare it impossible.

[matwood]

> No, as I said, I met an overweight person who consistently ate well and exercised (a college roommate). I have no idea how many calories they burned. By comparison, I ate much more and exercised much less and had very low body fat. Again, I have no idea how many calories I burned.

Typically when I'm told this either by people wanting to lose or people wanting to gain I just ask them to write down everything they eat for week. Guess what we learn at the end of the week? They really had no clue what they were eating. The skinny people were barely crossing 1500 cals and the overweight people were 2500-3000 and had zero idea. The other fun fact here is that food wise both of those are not very far away. A couple sweets or sugary sodas each day and you can easily cross over.

While there are likely exceptions and extremes (thyroid issues), the vast majority have zero clue about how much they really eat. This is why things like Weight Watchers work so well for many people. You get X points/day. Foods are worth differing amounts of points and when you hit zero stop. People quickly learn what foods are 'free' (veggies, most fruit) and load up on those and then plan the non-free foods to maximize taste/fullness/whatever.