At least, these foods could not be considered as essential. The core-concept also made nutritional and economic sense. Human diets all over the world are based on a set of staple foods. Most human beings rely on a few foods to supply most of their daily calories. A return to simpler food intake may have important biological advantages.
Bodies seem to work better when they have a simple, regular food supply - no surprises.
The core of a new, healthy, modern diet should be a small number of staple foods. The food allergy literature identified cow's milk proteins, gluten, and egg white as three of the most allergenic components of staple food in North America. The top three are followed by nuts, soya, citrus, corn, and then a scattering of other foods. The best foods overall were cooked vegetables and rice was staple grain with a lower incidence of problems. By using food lists in the allergy literature, and then keeping score of food reactions as patients reintroduced food, a critical path emerged with a list of foods which offered the best nutrition and the highest probability of tolerance.