The Pritikin Diet was created by Nathan Pritikin and enhanced by his son Robert Pritikin . It is a low-fat, high carbohydrate diet. (cf. Atkins diet) The theory is that we have an instinct to eat fat that was developed in the early days of man. The instinct was useful then because opportunities to eat fat were rare, and the fat helped to store calories to make it through the lean times. Now that fat is readily available, though, the instinct causes us to eat too much of it, adding unneeded weight and causing other bad side effects. The goal is that by learning to live on carbohydrates with a small amount of fat and exercising regularly a person can achieve the lean and healthy body of our remote ancestors rather than the overweight and unhealthy body of today.