He ate very low calories in order to keep from gaining weight on the high-carbohydrate diet. He failed to take any vitamins, minerals or other supplements on the false premise that his vegetarian diet could provide them. He undoubtedly suffered from an amino acid deficiency compounded by an essential fatty acid deficiency and further compounded by a refusal to supplement with vitamins and minerals. Amino acids from protein are the building blocks of life, and it is difficult to obtain all of the amino acids required by one's diet outside of eating meat, fish and fowl. The effects of these deficiencies take many years to manifest themselves, and the resultant disease can be just about anything in the book.
People fail to understand that the minimum requirement for carbohydrates in the diet is zero - none.
The good fat that is the most difficult to assimilate into the average diet is Omega-3, sometimes referred to as fish oil. Eating fish can provide the essential fats in Omega-3 but many fish do not have these oils. Fish such as canned tuna have the oils stripped away in processing. Fresh salmon filets are the best source from natural foods. The best supplemental source is Carlson's Cod Liver Oil with Lemon taken with meals in the amount of two tablespoons per day .