His arteries were clean when he was autopsied in his 60s. But Pritikin died of suicide after battling leukemia. Pritikin's diet is a step in the right direction for this generation's over-fat, over processed way of eating. However, in the long run, it may kill those who are not overfed. These diets assume that man has always been a hunter, which is open to debate, and that he has always eaten a diet high in protein and fat, which is not true.
Fats also produce ketones, which reduce hunger even more.
Refined carbohydrates, a large part of many overweight people's diets, are omitted completely from the menu or allowed only in small quantities. This is the best way for some people to eat. People differ in their food requirements for health. Excess urea is part of the cause of gouty arthritis. High-protein diets also increase chances of developing allergies, because proteins are potent allergens.