I can eat pretty much anything and not gain too much weight, without paying attention to anything, while another people can't. People really do process excess calories different: some turn more of it in to fat, whereas others just excrete it or turn it in to muscle tissue. I'm also the kind of person who can not eat anything all day and basically just be fine (I don't really get hungry fast).
I play the game on easy mode, whereas others play it on hard or even nightmare mode.