Food Combining

Food combining – briefly

Food combining gives your digestive system a rest. If you avoid foods at the same meal that compete with each other for digestion, then it is easier to digest the meal. Food combining can make it possible to avoid bloating, excess gas, constipation, diarrhea, and stomach pains after a meal.

This idea refers to the books and methods of Dr. William Howard Hay (“Health via Food“, 1929) and Dr. Herbert Shelton (“Food Combining Made Easy“, 1952). May they rest in peace. Many others have published in this subject. If you are looking for fast practical advice only, read this section only. If you are looking for an explanation and the scientific details of this idea, read the rest of this page. This subject, called “applied trophology“, was taught in medical schools until the 1950s. The advice of Drs. Hay and Shelton is to:

  1. Drink water, a smoothie, or soup before each meal, and then wait fifteen to twenty minutes before eating.  Drink nothing with the meal, except possibly a glass of red wine, if this is already your habit. Why no liquids with the meal? The water lubricates your digestive system before the meal, but it does not dilute your digestive enzymes during and after the meal. 

  2. Eat sweets, sweet fruits, or dessert alone or on an empty stomach. Else eat fruits at the beginning of the meal, and then wait another fifteen or twenty minutes. Why? You digest sweets and sweet fruits most rapidly of all foods. So if you eat them at the end of the meal, they are blocked internally and ferment, possibly causing inflammation in your digestive system.

  3. Separate (do not combine) starch (bread, pasta, potato, rice, cereal) and protein (eggs, fish, chicken, turkey, beef, cheese, dairy) at the same meal. Even in small quantities, always separate starch and protein at the same meal. Why? You digest starch in an alkaline environment with enzymes secreted in your mouth and small intestines. On the other hand, you digest protein in an acidic environment with enzymes secreted in your stomach. If you eat starch and protein at the same meal, they interfere with each other for optimal digestion, nutrient absorption, and waste excretion. This can cause incomplete digestion and inflammation of the digestive system. It can also cause chronic illness over time, according to Drs. Hay and Shelton. If you eat very, very small portions, this may not affect you. I eat like a horse.

These first three steps are the guidelines to apply this method. If you have little time to read, or if you look for a simple, practical method, then apply these first three steps consistently at every meal. Try it for a week, and see how you feel. If you skip a meal, then restart at the next meal. Many people see results in one to three weeks simply by always separating starch and protein at every meal, drinking water before the meal and not during the meal, and eating desserts or sweet fruits between meals or at the start of the meal.

intestines and wheatFood combining – in detail

Of course, the third step, the key step, separating protein and starch, excludes many common combinations you may already be used to, such as eggs with toast for breakfast, milk with cereal for breakfast, chicken with rice for lunch, and steak with potatoes for dinner. It also excludes most sandwiches, such as ham sandwiches, cheese sandwiches, or hamburgers, since they combine bread (starch) with ham, cheese, or meat (protein). Substitutes are possible, such as eggs with spinach or eggs with a green salad for breakfast, chicken or meat with steamed carrots or broccoli for lunch, rice with vegetables or a green salad for dinner, or possibly a sandwich with vegetables or avocado only. See Recipes for specific suggestions that combine foods according to this method. Recipes are to be organized and added.

Your genes are not your fate. Health is a choice. It begins in the mind. Your soul wants you to be healthy. Start to ask yourself – do I want to eat starch with this meal, or do I want to eat protein with this meal? The choice is yours. Try it for a week, and see how you feel. What matters more to you – your health or your habits? It is a question of changing your eating habits – for your health. The weight loss is a side effect. By the way, eat as much as you want. It is not necessary to count calories nor to restrict portion sizes.

Drs. Hay and Shelton also advise to:

  1. Let vegetables, salads, and fruits (whether citrus or sweet) be the basis of your healthy eating habits. This advice is trite, but bears repeating in a tidal wave of industrial and packaged foods.

  2. Eat proteins, starches, and lipids (nuts, seeds, and oils) in small quantities.

  3. Eat only one concentrated protein at each meal. This excludes combinations such as ham and eggs, ham and cheese, and beef and cheese (cheeseburger). Why? The required digestive enzymes that you secrete are slightly different for each type of protein. They can interfere with each other for digestion.

  4. Eat nuts and seeds (lipids) at the end of the meal, except for a teaspoon of olive oil with a salad or with vegetables. Why? You digest nuts and seeds the slowest of all foods.

Their advice has to do with digestive enzymes. The three main enzymes are protease to digest protein, lipase to digest fat, and amylase to digest carbohydrates. Related to food combining, both Dr. Hay and Dr. Shelton further recommend to:

  1. Stay at the table after each meal for at least fifteen minutes. Sit and digest. Why? Let your digestive system absorb the nutrients into your blood. Enjoy the company of any nearby kindred spirits.

  2. Leave at least four hours between meals with starch and meals with protein.

  3. Avoid milk and dairy (pasteurized cow’s dairy), or keep them to a minimum.

  4. cut all refined and industrial foods, except possibly certain fermented foods.
Clker-Free-Vector-Images / Pixabay

The main goal of food combining is to improve digestion. Again, if your digestion is healthy, you are healthy. What is optimal digestion? It begins with an absence of constipation, bloating, diarrhea, stomach pains, and excess gas. It continues with absorption and assimilation of the nutrients, minerals, and vitamins from your food into your blood, tissues, organs, and bones. Of course, good digestion ends with healthy waste excretion and leads to a healthy weight and healthy ageing. Try food combining for a week, and see how you feel. You have nothing to lose. Some people notice results in less than a week.




Most of all, the idea is not to mix foods that interfere with each other for digestive enzymes.

For a summary, see the table below.

  1. Optionally mix any food in list A (protein) with any in list B (versatile foods).

  2. Optionally mix any food in list C (starch) with any in list B (versatile foods).

  3. Never mix foods in list A (protein) with foods in list C (starch)).
list A (protein) list B (versatile foods) list C (starch)
eggs green vegetables bread, pasta, cereal
fish most other vegetables potatoes
chicken, turkey nuts & seeds rice
beef, liver olive oil (or flax or coconut oil) sweet potatoes, artichoke 
dairy (goat or sheep) herbs & spices oats, buckwheat, spelt, millet, quinoa
soy, tofu avocado adzuki beans, other beans, chickpeas, lentils, legumes/pulses

If you travel for the day, if you are in a hurry, you might carry an apple or two, a boiled egg or two, and a handful of nuts – to be eaten in this sequence, possibly with a fifteen-minute pause between each course. First, eat the apple, then pause, then eat the egg, then another pause, and lastly eat the nuts. Why? You digest fruit most rapidly, then protein less rapidly, and nuts the slowest of all. Each of these foods requires different digestive enzymes. This sequence also applies to snacks between meals. If you eat out at a restaurant, then look for meals that include vegetables with meat, fish, or chicken, and without bread nor potatoes. The vegetables nourish you. Most restaurants offer a meal of vegetables with meat or fish, if you ask for it. Vegetables with meat or fish is a traditional combination in many cuisines in many places. Vegan options include vegetables with rice, potatoes, or soy, and beans, plus spices.

Why does this work?

The good doctors refer to three factors to explain why this method works:

  • different organs to digest protein and starch, that is the protein in the stomach and the starch in the small intestines,

  • different optimal internal environments (pH) to digest protein and starch, acidic to break down the protein and slightly alkaline to break down the starch,

  • different enzymes that you secrete to digest protein and starch.
Different organs

When you start to eat protein, your stomach secretes hydrochloric acid and pepsin to prepare to break down the protein. This was first observed by Dr. Ivan Pavlov, a Russian physiologist, better known for his experiments about conditioning, salivating, and “Pavlov’s dogs”. In 1893, Dr. Pavlov managed to stick a tube in a live dog’s stomach to measure the secretion of hydrochloric acid, a wretched yet useful example of vivisection still common today. He then fed the dog protein and then fed him starch. Soon after the dog was fed protein, it secreted hydrochloric acid in his stomach. After the dog was fed starch, it stopped this secretion, delaying digestion and possibly causing indigestion, even besides having a tube stuck in its stomach.

When you start to eat starch, such as bread, potato, or rice, you to start to break down the starch in your mouth, secreting the enzyme called amylase. You continue to break down the starch in your small intestines. This is a slightly different process from digesting protein. If you eat starch and protein at the same time, the two digestive processes can compete with or undermine each other. Nothing becomes completely digested. The partly digested starch ferments. The partly digested protein putrefies. (Partly digested lipids become rancid.)

Different pH

You break down protein in your stomach in a very acidic environment. The pH is is between one and five, depending on biochemical individuality. The acid is necessary to break down the protein.

On the other hand, you digest starch first in your mouth and then in a slightly alkaline environment in your small intestines. If you eat both protein and starch at the same meal, the pH is not optimal to digest either the protein or the starch.

Different enzymes

Internally, you secrete hydrochloric acid and pepsin in your stomach during digestion. You convert pepsin to the protease enzyme to digest protein. You secrete amylase first in your mouth and then in your small intestines. You use amylase and other enzymes to digest starch. Enzymes can interfere with each other. Continuous interference can have long-term consequences for health.

Your digestive system is a tube about ten meters long from the mouth to the anus. Of course, food all ends up in the same place, either absorbed into the blood and retained in the tissues and organs, or else excreted in the stool and urine. However, if you combine foods in certain ways, the process of digestion can be much more efficient, avoiding constipation, bloating, excess gas, stomach pains, and indigestion. More efficient digestion consumes less energy and permits better absorption of the necessary minerals, vitamins, and nutrients into your blood.

Conmongt / Pixabay

Again, if you combine foods in less healthy ways, the enzymes and organs can interfere with each other for optimal digestion. This can leave your digestive tract with partly digested proteins and fermented starch. Over time, this partly digested food can accumulate and stick to the insides of your digestive system, causing inflammation. This does not need to be. The change begins in the mind first, if you let it.

Dr. Hay, the original author, further advised everybody to eliminate white flour, white sugar, and all things that contain them. This is good advice, but is not directly related to food combining.

Unrelated to food combining, pancreatic enzymes, also known as digestive enzymes, have been used therapeutically by some doctors for many years. This practice goes back to the work of Dr. John Beard and his book, ‘The Enzyme Treatment of Cancer and Its Scientific Basis“, originally published in 1911. More recently, William Donald Kelley, a dentist who  healed himself, and Dr. Nicholas Gonzalez have advocated therapeutic use of pancreatic enzymes against cancer. Do your own research, and think for yourself.

Dr. Shelton’s research

Dr. Herbert Shelton MD, author of “Food Combining Made Easy“, tried to measure the relative speeds of digestion of various food types. He found that the following food types are from the fastest to the slowest to be digested, independently of the personal metabolism:

  1. melon (to be eaten separately and first),

  2. sweet fruit, such as banana, grape, raisin, prune, date, mango, persimmon, and cherimoya

  3. sub-acid fruit, such as apple, pear, plum, peach, apricot, blueberry, cherry, fresh fig, and soursop,

  4. acid fruit, such as lemon, lime, grapefruit, pineapple, pomegranate, orange, and kiwi,

  5. green and non-starchy vegetables, such as spinach, broccoli, celery, cucumber, kale, radish, parsley, onion, garlic, collard green, chard, asparagus, turnip, dandelion, Brussels sprout, cabbage, and paprika,

  6. starchy vegetables, such as beet, carrot, sweet potato, artichoke, pumpkin, some squash, cauliflower, and potato,

  7. starches, such as cereals, grains, rice, adzuki beans, most beans, pasta,

  8. proteins, such as egg, sardines, other fish, chicken, turkey, beef, dairy, soybeans (tofu), and

  9. fats, such as pumpkin seeds, almonds, walnuts, flaxseed, olive oil, tahini, and avocado.

Dr. Shelton tried to quantify average transit times. On the other hand, what is rapid and healthy digestion for one person may be slow and unhealthy for another. Some people have a naturally more rapid digestion than others. Again, the key is to know yourself and to avoid constipation, bloating, diarrhea, stomach pains, and excess gas. Shelton advised always eating more rapidly digested foods before more slowly digested foods, possibly allowing fifteen minutes between food types, depending on the person and the personal metabolism.

On the other hand, for breakfast, I often drink a smoothie, including a carrot (or red beet or both), spinach, lemon, apple, ginger, hemp seeds or pumpkin seeds, stevia, and water. This mix causes me no indigestion, no diarrhea. It has minerals and vitamins necessary for me. However, my garden is not your garden. This may or may not be healthy for you, depending on your personal metabolism and possibly also on your toxic load.

Biochemical individuality

To repeat, some people tolerate combining different fruits and vegetables better than other people. Some combinations or too much fruits and vegetables at one serving can cause some people diarrhea, stomach pains, or indigestion. When you start to change your eating habits, it is better to start slow and go slow. If you make only one change at a time, then you can easily reverse this. Others do not tolerate combining certain types of fruits and vegetables at all. Tolerance for this purpose is defined as a rapid or regular and complete digestion without diarrhea, excess gas, nor indigestion. Biochemical individuality may explain this at least partly. Listen to your body.

Food combining can be confusing at first. For example, a sweet dessert at meal-end, such as chocolate chia pudding made of chia seeds (lipids), cocoa or carob or ginger, and pure stevia, can be a healthy combination, since it has lipids and has no sugar and no starch. To keep this simple, focus on the three first suggestions at the start of this page.

The two most challenging suggestions to apply are:

  • to separate (do not combine) starch and protein at the same meal and
  • to eat dessert only between meals (not at the end of a meal).

This probably requires changing your habits, which many people, perhaps all of us, hesitate to do. We are all creatures of habit.

What do you value more – your health or your habits?

superior knowledge about health?The critics

Note that the idea of proper food combining for health has many critics and skeptics. Most of the criticism is theoretical. Most of the critics and skeptics have never read Dr. Hay’s nor Dr. Shelton’s book nor any other book about food combining. None of the critics whom I know have actually tried food combining for themselves. 

The critics point out that people have been eating starch and protein together for a long time, so why is everybody not becoming overweight and ill? Look around. They further point out that many foods, such as broccoli or beans, contain both starch and protein, so separating them is neither possible nor desirable. This is true, but misinterprets the food combining idea, which has to do with more concentrated proteins (more than fifteen percent protein content), such as eggs, fish, and meat.

The critics are very intelligent and very well organized. They point out that the pancreas can secrete different digestive enzymes, such as amylase, protease, and lipase at the same time, making multi-tasking possible, digesting vegetables, fruits, starch, protein, and nuts in parallel. This is true, but overlooks the point that digestion is only optimal and complete, if the enzymes, organs, and environments do not interfere with each other during the process. The result of inefficient, incomplete digestion is an accumulation of partly digested, putrefied proteins in the walls of the digestive system. Repeated, continuous incomplete digestion can also result in constipation, bloating, diarrhea, stomach pains, or excess gas, depending on the person.

The critics often try to ridicule the idea of “better digestion”, which they claim cannot be measured. Naturally, you, and only you, can evaluate your own digestion, optimal, sub-optimal, efficient, inefficient, bloating, gas, stomach pains, heartburn, diarrhea, constipation, or healthy excretion. If your digestion is healthy, or if you make it become healthy, especially over time, then you are healthy.

Lastly, the critics point out that no clinical trial has ever been done to prove that food combining is safe and effective. Nothing prevents you from doing an experiment on yourself, trying food combining for yourself and then drawing your own conclusions for your own health. It will not cost you anything more than what you are already paying for food to try it. It does not require you to change what you eat, but merely how you compose each and every meal. Try it for a week or two or three. Then see how you feel.

Regarding published science, no clinical trial has ever been done to prove that water is a cure for extreme dehydration nor that prunes have a laxative effect, yet we all know these are true. As Dr. Shelton said, “look for the truth, and your health will follow.” The truth does not always conform to the opinion of the majority. Skepticism is healthy, but let us not overlook the simple facts (different organs, pH, and enzymes) and also biochemical individuality.

Vegan or paleo?

Nota bene. Food combining is both vegan– and paleo-friendly. In other words, combining foods properly, you can choose either vegan or paleo eating habits (or ketogenic, macrobiotic, Gerson, or Budwig), your choice. 

Do you know your ABO blood type? While food combining, you can also apply blood type eating, another idea for health via food.I suspect though I cannot prove that food combining may be more useful for blood type O carnivores than for blood type A vegans. If you have blood type O, you tend to digest animal protein (meat, fish, or eggs) and fats (nuts, seeds, and oils) more rapidly than blood type A does. O may have other metabolic differences from A.

Individual interpretations

Many authors have written on the subject of food combining. Naturally, they each tend to have their own point of view based on their own experience, observations, and biochemical individuality. The original scientific references are the books by Drs. Hay and Shelton. These books and ideas have withstood the test of time. Hay also wrote about the acid-alkaline balance, another idea for health via food. Years ago, while Hay was alive, food combining was called the “Hay diet“. In this twenty-three-minute video, Dr. Mercola and Dr. Pickering discuss food combining.


For healthy digestion, food combining works for many people, including me. Both Dr. Hay and Dr. Shelton reported using this method to cure many patients of chronic illness. If you doubt this, then read their books online. Do your own research. If you have digestive problems or discomfort, try food combining for a week or two or three. Then see how you feel. You have nothing to lose. Food combining can even be cheap. Many people see results in one to three weeks.

What do you value more – your health or your habits? 


Hay MD, Dr. William Howard, “Health via Food“, Sun-Diet Health Service, 1929 
Shelton MD, Dr. Herbert, “Food Combining Made Easy“, 1952
Marsden, Kathryn, “Food Combining“, Piatkus, 2005
Walb MD, Dr. Ludwig, “Original Haysche Trennkost“, Haug, 1987 (in German)
Le Tissier, Jackie, “Food Combining for Vegetarians“, Thorsons, 1992

Wright MD, Dr. Jonathan, “Why Stomach Acid Is Good for You“, M. Evans, 2001
Beaumont MD, Dr. William, “Experiments and observations on the gastric juice, and the physiology of digestion“, 1833

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