Well, not gonna get into an argument but I don't buy the DNA thing, since at the time of our evolution, men were a hell of a lot broader and more muscular then what's considered 'sexy' today.. you think the hunter-gatherers looked like Bradd Pitt in Fight Club? Read up a lil and you'll find out about the significantly larger joint sizes of our ancestors, which should tell you a lot about what we used to look like. But that's another story altogether.
What I always go by: if you are confident and happy in yourself, whether you're lean, skinny, fat, muscular, whatever - this will be a much bigger factor than any degree of aesthetics. And what is considered aesthetically pleasing will differ from person to person anyway.