[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.