From what I know the only diet that has some backing to actually working is the Ornish diet. If you go to his
website and read the information, this very strict regimen or diet, exercise, meditation, etc. has been shown to reduce artherolsclerosis (hardening of the arteries) .
That said, most of these diets do have you eating in a healthy way, and our bodies naturally respond to eliminating sugars, white flours, refined foods, animal byproducts, etc.