Very intersting idea.
Maybe a way to make it work would be not actually having 100 different models, but have some kind of scaling of the models ingame. For example the shoulder part, chest, stomack, arms and legs could be scaled based on your activities. If you eat too much and don\'t walk a lot, you would become fat, if you fight a lot and walk, but also eat a lot, your massive, but not fat. etc etc