[ericd]

Sorry for the hyperbole. I think you're being a bit uncharitable, though, I'm of course not basing this entirely on myself. Lots of people I know have a bar for being satiated that maintains weight without effort. But many clearly do not. Is it obvious why some do, and some don't? It's clearly not down to willpower.

I suppose you'd say that some areas experienced more evolutionary pressure to eat as much as possible than others due to differences in food security?

But being hungry/unsatiated is distracting and can decrease your performance on every other task you do, so I don't really agree that there's no counterpressure. And I doubt that people in even those less food secure regions are just hungry all the time, like some obese people here describe being. It really seems like something just gets messed up in the signalling, which makes it seem more like a health problem/malfunction than some built-in evolutionary drive that doesn't fit the modern world.