if you didn't want people to think you were comparing your players' intelligence to that of animals...which is precisely the thing that makes an animal overeat when it shouldn't...then you probably shouldn't have compared your players to animals that lack the intelligence to avoid overeating.
Once again I'm reminded of
this:
The key assumption throughout all these games is that if a gaming experience is to be intelligent (and all Fantasy Heartbreakers make this claim), then the most players can be relied upon to provide is kind of the "Id" of play - strategizing, killing, and conniving throughout the session. They are the raw energy, the driving "go," and the GM's role is to say, "You just scrap, strive, and kill, and I'll show ya, with this book, how it's all a brilliant evocative fantasy."
It's not Illusionism - there's no illusion at all, just movement across the landscape and the willingness to fight as the baseline player things to do.
The same essay goes on in an interesting way, that is relevant to this thread:
The Explorative, imaginative pleasure experienced by a player - and most importantly, communicated among players - simply doesn't factor into play at all, even in the more Simulationist Fantasy Heartbreakers, which are universally centered on Setting.
I think this is a serious problem for fantasy role-playing design. It's very, very hard to break out of D&D Fantasy assumptions for many people, and the first step, I think, is to generate the idea that protagonism . . . can mean more than energy and ego. These are fine things, of course, but it strikes me that playing with them as the sole elements provided by the players is a recipe for Social Contract breakdown.
A lot of the posts in this thread seem to me to be addressing the relationship between player contributions (energy, ego, . . . anything else?), setting, and GM-centred methods for either avoiding, or managing, social contract breakdown.