Hay diet

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 food into three groups: alkaline, acidic, and neutral. (Hay's use of these terms does not completely conform to the scientific use, i.e., the pH of the foods.) Acid foods are not combined with the alkaline ones. Acidic foods are protein rich, such as meat, fish, dairy, etc. Alkaline foods are carbohydrate rich, such as rice, grains and potatoes. It is also known as the food combining diet.

A similar theory, called nutripathy, was developed by Gary A. Martin in the 1970s. Others who have promulgated alkaline-acid diets include Edgar Cayce, D. C. Jarvis, and Robert O. Young.

In 1905, Hay seems to have had an episode of acute heart failure following running for a train. As a result he discovered that he had Bright's disease (hypertension with nephritis) with a dilated heart, a condition with a poor prognosis at the time. Hay started looking for ways to improve his condition. He first turned to a vegetarian diet and restricted his eating to once a day in the evening. Then he gave up coffee and a few months later he quit smoking tobacco. After three months of the new regimen his weight had dropped from 225 lbs. to 175 lbs. and he noticed improvements in his health. Motivated by this experience, Hay spent the following decade studying naturopathy, orthopathy and food combining in efforts to reduce as he termed it "the vast quantities of acid waste that result from wrong selection and combination of the daily foods". He claimed that fruits and vegetables produced alkaline 'end-products' when they were metabolized, while processed and refined foods resulted in acidic 'end-products' after digestion. His theories went on to encompass food-combining; stating that incorrect combinations of foods would cause even alkaline foods to leave a less desirable acidic digestion end-product.

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