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. Food allergies may result in digestive and absorptive problems, nutrient deficiencies, and immune impairment common to allergies. EFA intake is not considered at all in these diets. They do suffer strokes due to lack of vitamins C and E, and kidney damage and osteoporosis due to high protein. The fats in their diets come from fish and marine mammals containing large concentrations of highly unsaturated w3 fatty acids.