If you're fat it IS YOUR FAULT. PERIOD. The genetics issue is bogus. It is because so very few people actually suffer from a genetic condition that causes obesity. Some people have slower metabolisms due to genetics, but that doesn't make them fat. They can speed it up with exercise or how they eat. Or they can simply eat what their body requires at that moment in their life. Eat more than you need and you get fat. Simple. It's your fault if you do, no one else's. That includes marketing departments and advertisers. If you can't resist their selling tactics, you're a weak-mined fool.
You control your own life. You must live with the consequences of your actions.