There are plenty of fad diets based upon sophistic belief and ignorance rather than a sensible sense of balance. Fad diets are typically based upon fixation of one aspect of nutritional physiology.
Many fad diets have phases, designed to provoke an initial rapid weight loss, followed by transition and maintenance phases. These unduly stress the body in the beginning and are ill-advised in the long term.
The Atkins Diet and South Beach Diet are exemplary fad diets that have retained popularity for decades. The Zone Diet is more recent, popularized by celebrity endorsement. All are health-adverse by poor food selection and wrong emphasis.
The Atkins Diet is a weight-loss diet, designed to quickly reduce fat by ketosis: forcing the body to use stored fat for fuel by starving it of carbohydrates. In largely eliminating the healthiest foods – fruits and vegetables – in its earliest phase, the diet shocks the system. Like most fad diets, the Atkins Diet recommends eating far too much of an ill-advised selection, particularly fat and protein.
The more moderate South Beach Diet generally follows the Atkins Diet formula of promoting weight loss by sacrificing healthy carbohydrates in favor of fats and proteins, though the diet, designed by a cardiologist, is aware of favorable fats.
While Atkins promotes continual minimization of carbohydrate consumption, South Beach lowers carbs for weeks. The South Beach Diet advocates eating often but little, thus damaging the system over the long term by not allowing sufficient time for autophagy to reap its benefits.
Eat as much protein as the palm of your hand, as much non-starchy raw vegetables as you can stand for the vitamins, enough carbohydrates to maintain mental clarity because the brain runs on glucose, and enough monounsaturated oils to keep feelings of hunger away. ~ American biochemist Barry Sears, author of The Zone Diet
The Zone Diet is based upon the rigid regime of eating 40% carbohydrates, 30% protein and 30% fat (40:30:30) every meal. This is also a long-term low-carbohydrate diet, as carbohydrates should be at least 60% of dietary intake.
The philosophy behind the Zone Diet aims at the supposed evil of insulin: eating carbohydrates increases insulin production, causing the body to store fat. This entirely misses the point that gaining weight is the most obvious signal of overeating.
The Zone Diet is complex, with a long list of forbidden foods, but meat is not one of them. The Zone Diet advocates overeating, especially sating on saturated fats.
Feelings of hunger are an essential dietary regime for those unhealthy enough to feel them. With a proper diet, hunger ceases, replaced by an empty feeling: the need for nutritional fuel.
There is a vegetarian Zone Diet, heavily based upon soy protein, ignorantly ignoring the dangers of indigestible soy that has not been fermented.
Most fad diets, such as the above, falsely advertise dairy and meats as healthy choices. Almost all fad diets advocate overeating, however inadvertently.