Sure, some bodies don't, some bodies do. There is nothing natural about the body ability to eat whenever it feels like and as much it feels like and not get fat

Sure, some bodies don't, some bodies do. There is nothing natural about the body ability to eat whenever it feels like and as much it feels like and not get fat. A lot of cats and dogs will get fat if we give them unlimited access to food as well and others won't (well, at least some cats won't). Humans are not special snowflakes.