ArticleslgStudy

science

Hay diet

Hay diet is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hay diet rather than just read about it. In short: 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 diet — main illustration
Hay diet — illustration

Key takeaways

  • Hay diet belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Hay diet to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Hay diet from memory before moving on to harder problems.

Reference excerpt

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.) Acidic 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, Luigi Costacurta, D. C. Jarvis, and Robert O. Young.

History

In 1905, Hay purported to have had an episode of acute heart failure following a sprint towards 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.

Any carbohydrate foods require alkaline conditions for their complete digestion, so must not be combined with acids of any kind, as sour fruits, because the acid will neutralise. Neither should these be combined with a protein of concentrated sort as these protein foods will excite too much hydrochloric acid during their stomach digestion. The Hay System promoted eating three meals per day with meal one being what the diet considers to be alkaline foods only, meal two composed of what the diet considers to be protein foods with salads, vegetables and fruit, and meal three composed of what the diet considers to be starchy foods with salads, vegetables and sweet fruit; with an interval of 4.0 to 4.5 hours between each meal. The Hay diet was popular in the 1930s and many restaurants offered 'Hay-friendly' menus; followers of his dietary advice included Henry Ford and Man Ray. In this period Hay was criticized in the Journal of the American Medical Association (JAMA) as a food-faddist and separately for advocating that a patient with type 1 diabetes on the Hay diet should stop taking insulin. In 1935, Stewart Baxter showed that the pancreas secretes digestion enzymes simultaneously regardless of whether the food eaten is carbohydrates or protein, contrary to one of the central propositions of the diet. Currently, the theory that carbohydrate and protein rich foods should be eaten separately is considered "unfounded" because it ignores the fact that carbohydrate rich foods contain significant amounts of protein. Eating protein separately from carbohydrates also tends to cause the body to burn the protein as an energy source rather than to build muscle. Nevertheless, despite continual criticism over lack of a scientific basis, the Hay diet and its variants, such as the Kensington diet and the Beverly Hills Diet, remain popular, with actors such as Elizabeth Hurley, Helen Mirren and Catherine Zeta-Jones following food-combining diets.

Studies 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.

See also Food combining Alkaline diet Fit for Life List of diets

References

Further reading Boyer, Josephine, and Katherine Cowdin (1934). Hay Dieting: Menus and Receipts for All Occasions. With a foreword by William Howard Hay. New York, New York: C. Scribner's sons. Hay, William Howard (1933). Health Via Food. Ed. and rev. by Rasmus Alsaker, with a special introduction by Oliver Cabana, Jr. First printing, June, 1929; Tenth printing, February, 1933. East Aurora, New York, Sun-Diet Health Foundation. Hay, William Howard (1935). Weight Control. New York: Hay System.

Worked examples

Example 1 — a first encounter with Hay diet

Start with the simplest possible case. Write down what Hay diet claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hay diet before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hay diet ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hay diet

In research
Hay diet appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Hay diet in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Hay diet is common in secondary-school and first-year university syllabi. It links to neighbouring topics Diets, Fad diets, so understanding it makes those chapters shorter.
In everyday life
Look for Hay diet outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Hay diet” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Hay diet in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Hay diet means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Hay diet out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hay diet in simple terms?

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.

Why does Hay diet matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hay diet?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hay diet.

Tags

  • Diets
  • Fad diets

Keep exploring