Dr. Hay diet

The Dr. Hay diet (also called the Hay Diet) is a nutrition method developed by the New York physician William Howard Hay in the 1920s. It claims to work by separating out food groups into those which are "alkaline, acidic and neutral". Acid foods are not combined with the alkaline ones. "Acid" foods are protein rich, meat, fish, dairy, etc., and "alkaline" the carbohydrate-rich starch foods like rice, grains and potatoes.

It is also known as the food combining diet, and many authors have written books expressing its merits and selling recipes.

The food-combining diet has been the subject of one peer-reviewed randomized clinical trial, which found no benefit from the diet in terms of weight loss.

A similar theory, called nutripathy, was developed by Gary A. Martin in the 1970s. Others who have promulgated alkaline-acid diets include Robert Young, Herman Aihara, and Victor A. Marcial-Vega..