Genes certainly contribute to the shape of and to our ability to control the shape of our physique.
Some people have it easier than others.
But follow a fat person around for a day and then follow a skinny person around and you will observe vastly different behaviors. Most people piss and moan because they have not had much success with "dieting" or "working out." Their Men's Magazine and their Ab Isolator's "toning regimens" have failed them and they got sick and light-headed from taking all of that ephedra. Usually, their doc tells them to stop taking it so they pick up something with "ma huang, NOT ephedra," as they put it... oh lord. Same sh-t, different day. Or, if they're trynna get big, they start taking creatine and keep lifting tinkerbell weights and keep eating like an anorexic tinkerbell. No progress. So they arrive at the conclusion that god wants them skinny or god wants them fat.
It's ALL genetics!
Not too long ago, America was on a fat-free kick. Fat was the demon converting all of us into lardos, so food manufacturers and retailers stocked shelves with fat-free and low-fat versions of our favorite junkfood. Look at snackwells... "fat free." Of course, it's all made out of sugar! Nobody realized that carbohydrates are not only addictive but have a profound impact on hunger/satiation mechanisms AND weight and mood. No wonder nobody was getting fit.
I have a friend who is about 70 lbs overweight and has been that way for a while. He goes to the gym everyday to lift and do a half hour of cardio (which is too much, but let's not stop here) and he eats one meal a day... yep, eats one big, 2,000 Calorie meal in the afternoon and spends the rest of his day sipping on fruitjuice and eating candybars. Must be genetics.
Another friend doesn't eat breakfast, goes to the gym to use the ab machine, the hip abd/adductor machines (male, mind you), and spends most of his time marching on the stairmaster at the speed of an obsese middleaged woman. This friend doesn't eat breakfast, has a cornmuffin for brunch, has a salad, some bread and a banana with some other carbs for lunch, and... well, he gets about one good serving of protein every evening, usually a piece of fish with dinner. He's losing weight fast, won't deny him that, but he'd like to "tone up." Looks more like he's shriveling up. I argued with him for ten minutes that a banana is not an adequate source of protein but he refused to even entertain the idea he could be wrong, let alone go look it up. Another case of genetics at work.
The guys in my family have horrible physiques and although I'm not picture perfect, I don't resemble them in that aspect. I lift smart and I eat smart AND I am sitting in front of a computer or at a desk for at least ten hours a day! I must be some kind of a mutant or maybe I was switched at birth.
DWK