[ska]

Yes, there are 2nd order effects, and there are also a bunch of assumptions in basal rate calculations, and conversion efficiency etc. Your assumption that the current day surplus doesn't carry forward (i.e. that as someone gets heavier they done increase intake to account for increased basal metabolism) is also a pretty strong one.

Anyway I could have been clearer, but my point wasn't to suggest that you would end up exactly 200lb heavier, but that your calorie surplus adds up to roughly 200lb - exactly what happens to it depends on a lot of things.

This is response to someone who suggested they hadd seen a lot of clearly obese people who couldn't have got there on a few hundred extra kcal per day - however that doesn't seem accurate.