Diets don't work. They don't work because they're temporary, but fatties are too fucking stupid to realize that. They don't have the brainpower to realize that if you go back to your old eating habits, you're going to get fat again. They lack the connections in the brain to realize that more food = more fat. So yeah, diets don't work. A permanent change to a healthy diet (singular, not plural) will have permanent results.