I saw a documentary once about people who effortlessly remain at a healthy weight, and their activities were tracked for a couple of weeks, revealing;

* Unexpected bursts of random activity like dancing for a few minutes or moving heavy furniture, that these people didn't even notice, while still doing no deliberate exercise,

* Binging like suddenly eating a whole pizza, but then eating next to nothing the next day because "too busy", without putting thought into it. This would be bad for you on the scale of months, but fine over one week.

So, of course, they made up for all the calories they seemed to be taking in. There's an implication that this is instinctual, or just fortunate habits. In my case, I also burn energy arguing, puzzling, and worrying, and I naturally radiate more heat than most, and although I'll happily try to eat a whole tiramisu by myself I seem to have a small stomach and don't attempt it often anyway. So although I think of myself as lazy and gluttonous, I guess I'm just fortuitously, circumstantially not. Imprison me in a restaurant, I'd probably get fat.

Edit: right now I'm idly eating chocolate while I type. But I have no other food in the house, except three bananas. That's because I didn't organize it, because I'm lazy, but what "lazy" really means is a complex subconscious strategy, I think.