Genes contribute to the causes of obesity in many ways, by affecting appetite, satiety (the sense of fullness), metabolism, food cravings, body-fat distribution, and the tendency to use eating as a way to cope with stress.

i'll accept metabolism, primarily. body-fat distribution is a consequence of metabolism.

but, if you're going to tell me that you're fat because you have genetic factors that affect your appetite and there's nothing you can do to stop it, i'm going to laugh at you. yet, that seems to be what a lot of the argument is based on.

"well, sure i ate the entire cake. i was hungry! it's genetic!"

go take a holiday in africa and come back and tell me how you feel about that, now.