I think you’re mostly right, I think the difference in people may be that some more calories doing the same thing, which of course would be their metabolisms. I recall a study done years ago that gave the amount of calories burned (I think they measured it by how much O2 was used—but it’s been a long time) by people who simply fidget a lot. It was amazing how many calories they fidgeted away. I tried to start fidgeting, but I guess it’s not in me, because it didn’t work! LOL
I think when someone states it’s only calories in vs calories out, they are giving a very simplistic answer to a very complex issue.
On the other hand, I KNOW I eat more than I should. So, Obama should make all food taste gross and most of us would lose weight!