Fermentation causes irritation and poisoning. Proper food combining removes fermentation as a cause of indigestion (though there are many other conditions that can cause digestive problems, such as overeating; eating hurriedly or when tired, worried, angry, fearful, grieved, etc.; or when you are in pain or have a fever or inflammation).
The successful results obtained through the utilization of me food combining rules can be explained and substantiated by the facts of physiological chemistry, particularly the chemistry of digestion.
No food program, nor any food combining program, will cure disease. Healing can be effected only by removal of the causes of disease. Incorrect food combinations can be an important cause.
Food ClassificationFoods vary widely in character and nutritional constituents. This classification of food categories will provide clarification and greater understanding of our discussion of the principles of digestive physiology and chemistry that decree correct food combining.
ProteinsAll foods contain some protein, and the amounts of protein in different foods vary widely. We classify as protein foods those that contain a comparatively high percentage of protein—these are the concentrated protein foods. Such foods include:
- Animal proteins
Seeds & Nuts - 2 to 3 hours.
Egg yolk - 30 min Whole egg - 45 min.
Fish (white) - 30 min. Fish (fatty fish) - 45 min. to 60 min.
Chicken - 1 h 30 min to 2 hours
Beef, lamb - 3 to 4 hours
Pork - 4 h 30 min to 5 hours.
CarbohydratesThe carbohydrates are the starches and sugars.
The starchy vegetables are potatoes (all kinds), mature corn, parsnips, and Jerusalem artichokes; the mildly starchy vegetables are carrots, globe artichokes, beets, winter squash, cauliflower, rutabaga, salsify and several others.
The combination foods (starchy proteins) referred to under the protein category are classified as starches for purposes of food combining. These include dried and fresh legumes, grains, peanuts, cashew and chestnuts. Green vegetable proteins (to be combined as starch) include peas in the pod, lima and other beans in the pod, and mature green beans in the pod. Sprouts contain significant amounts of protein, especially in the early stages.
Digestion time of carbohydrates:
Starches and mildly starches: 60 min.
Grains: 90 min.
Legumes & Beans: 90 min. Soy beans -120 min.
Nonstarchy and green vegetablesLettuce, celery, endive, chicory, cabbage, broccoli, brussel sprouts, collards, spinach, dandelion, beet tops, turnip tops, chard, chinese cabbage, chive, chicory, mustard, turnip, egg-plant, green beans, cucumber, sorrel, parsley, rhubarb, onions, leeks, garlic, zucchini, escarole, cardoon, bamboo sprouts, asparagus, radish, pepper, fennel, etc.
Raw salad vegetables 30 to 40 min.
Steamed or cooked vegetables 40 min.
Root vegetables 50 min.
FatsThe recommended fats are nuts, seeds, avocados, olives and coconut.
The other fats are not recommended (vegetable oils, meat fats, butter, etc).
Avocado and olives: 45 min to 2 h (depending what they are eaten with)
Coconut (fresh): 2 h 45 min
FruitsThe acid fruits are those with the tart flavors, for example, citrus (orange, grapefruit, lemon, lime), pineapple, strawberries, kiwifruit, promenagrate, sour apples, sour grapes, and sour plum. Tomatoes are also considered acid fruit (without the sugar content of other acid fruit).
The subacid fruits are those that possess a slightly acid flavor (but not tart), such as pears, peaches, cherries, apricot, sweet apples, sweet grapes, fresh fig, papaya, cherimoya, mango, etc. Grapes, for example, can be acid, subacid or sweet.
The sweet fruits are those that are rich in sugar and taste sweet-bananas, persimmons, sweet grapes and all dried fruit.
Melons: Watermelon, canteloupe, honeydew and many others. (See charts)
Melons - 20 min to 30 min.
Acid and subacid fruits - 30 min. to 40 min.
Syrups and sugarsAll kinds of sugar, syrup and honey (not recommended).
Food Combining RulesWhen foods are eaten in incompatible mixtures, and the efficiency of digestive enzymes is inhibited, it is subjected to decomposition in the digestive tract. If the digestive enzymes cannot perform their intended functions of breaking down and hydrolyzing the food (adding water from the body's reserve supply), bacterial decomposition may occur, resulting in fermentation and the production of alcohol and acetic acid.
A simple way to avoid production of these poisonous substances in the digestive tract is to learn and implement the hygienic guidelines for food combining.
Fruits* Never eat acid foods with carbohydrate foods.
Starch digestion begins in the mouth with the action of the enzyme ptyalin. Ptyalin requires either an alkaline or neutral medium. Ptyalin is destroyed by even a mild acid. If fruit acids-or any acids-are taken with carbohydrates, especially with such foods as potatoes, beans, bananas or dates, digestion will be inhibited or prevented and fermentation may occur.
The combination of citric, malic and oxalic acids in tomatoes (which are released and intensified by cooking) interferes drastically with starch digestion.
The acetic acid in a teaspoonful of vinegar can suspend salivary digestion.
* Do not eat acid fruits with proteins.
Citrus, tomatoes, pineapple, strawberries and other acid fruits should not be eaten with nuts, cheese, eggs or meat. Acid fruits inhibit the flow of gastric juice. The digestion of protein requires an unhampered flow.
Although Dr. Shelton includes in this rule the prohibition of citrus and tomatoes with nuts and cheese, he goes on to say that nuts and fresh cheese do not decompose when used with acids, but have their digestion delayed.
Many Hygienists use tomatoes with nuts and believe they cause no problem. Citrus fruits present a different situation, due to the sugar in the fruit, which can ferment if its digestion is delayed by the nuts. Various experiments with the use of citrus fruits combined with nuts have produced differing results. Some Hygienists continue to use citrus with nuts.
If sweet oranges are used at the same meal with nuts, the precaution of waiting thirty to sixty minutes after eating the citrus is sometimes observed. Grapefruit might be better suited to combining with nuts, since it usually has a much lower sugar content.
Such acid-protein combinations as sour salad dressings and acid fruit drinks used at conventional meals serve as a check to hydrochloric secretion.
* Do not combine sweet fruits or sugars with foods that require a long digestive time-foods such as proteins, starches and acid fruits.
The sugars in sweet fruit should be tree to leave the stomach quickly, in perhaps fifteen or twenty minutes, and are apt to ferment if digestion is delayed by mixture with other foods. No digestion of sugars takes place in the mouth or stomach; fermentation is inevitable if sugars of any kind are delayed in the stomach awaiting the digestion of starch, protein or acid fruit.
Sugar-starch combinations cause additional problems. When sugar is taken, the mouth quickly fills with saliva, but no ptyalin is present. Ptyalin is essential for starch digestion. If starch is disguised by sugar, honey, molasses, syrup or sweet fruit, the signals are scrambled and digestion is impaired. Pure sugar also has a marked inhibiting effect on the flow of gastric juice and on gastric motility. No other food depresses the action of the stomach and the desire for food as does sugar.
* Acid fruits may be used with subacid fruits.
This is an acceptable combination, though some subacid fruits are rather high in sugar and the acid fruit may delay the sugar’s normally quick exit from the stomach. However, there is no sharp line of division between the acid and subacid fruits. If combining subacid fruit with acid fruit, it is better to use only the less subacid fruit.
Tomatoes should not be combined with subacid fruit, nor any other kinds of fruit. They are best combined with the salad at a meal at which no starchy foods are served.
* Do not use acid fruits with sweet fruits.
Acid fruits are best used alone (a single variety), but if used in combination with other acid fruits, this is considered an acceptable combination.
* Subacid fruits may be used with sweet fruits.
There is no sharp line of division between subacid fruits and sweet fruits. When using subacid fruits with sweet fruits, it is best to use the sweeter varieties of subacid fruit.
Some people prefer to eat bananas alone, but most people have no difficulty in combining them with subacid and other sweet fruit at a fruit meal.
It is best to have sweet fruits at a fruit meal combining only with lettuce and/or celery. Since fruits are usually high in acids or sugars, they do not combine well with other foods.
* Dried fruits should be used sparingly.
Use but one kind at a meal, in small amounts, combined only with subacid fruit and/or fresh sweet fruit and/or with lettuce and/or celery. Overeating of dried fruits will often bring on symptoms similar to a “cold”. The sugar concentration is naturally greater in fruits which have been dried. Some dried fruits, esp. dried apricots, should be soaked overnight to replenish the missing water. Dates are usually used without soaking, figs or raisins can be used either way. If they are rather hard, soaking will soften and improve them.
* Take Melons Alone
Do not consume melons with any other foods.
This rule has been somewhat under question in recent years. It have even found advisable not to mix two different varieties of melon at the same meal.
Many people who have complained that melons did not agree with them have no trouble handling them when eating only melon at a meal. Yet, certain Hygienic professionals are offering more than one variety of melon at a meal (even melons in combination with grapes or other subacid fruit). If you want to experiment with these combinations, do it sparingly and carefully. But if you have a history of digestive problems, don’t do it at all.
Melons are more than 90 percent liquid and leave the stomach quickly if not delayed and fermented by combining with other foods. Dr. Vetrano says, “Melons are best taken alone because the sugar and other nutriments are in a less stable form than the nutrients of other fruits. If you refrigerate watermelon juice for only ten minutes, its flavor, color and composition markedly change. It decomposes much more quickly than other fruits. Consequently, if it is held in the stomach awaiting the digestion of other foods, it will decompose (ferment) and cause a great deal of gastric distress.”
* Do not combine fruit with any vegetables except lettuce and celery.
It is best not to combine fruits with vegetables (especially cooked vegetables), proteins or starches because if such a combination of food is eaten, the digestion of the fruit will be delayed and subject to fermentation. Lettuce and celery, however, may be combined with any fruit except melon, and will cause no problem.
Protein-carbohydrate* Never eat a concentrated protein and a concentrated carbohydrate at the same meal.
Physiologically, the first steps in the digestion of starches and proteins take place in opposite media—starch requiring an alkaline medium, protein requiring an acid medium in which to digest. The enzyme ptyalin (salivary amylase) that initiates starch digestion is active in an alkaline medium only and is destroyed by a mild acid. On the other hand, pepsin, the enzyme that initiates protein digestion is active only in an acid medium. If starches and proteins are eaten together, the acid gastric juice destroys the ptyalin and puts an end to salivary digestion of starch. That the presence of the undigested starch in the stomach interferes with the digestion of protein is shown by the presence of undigested protein in the stools. Physiologists have shown that undigested starch absorbs pepsin and this will surely interfere with digestion of protein.
If a food that is a natural protein-starch combination is eaten alone (starchy protein), the body is capable of modifying its digestive juices and timing their secretions in such ways that digestion can go on with a fair degree of efficiency. But when a starch food and a protein food are eaten at the same meal this precise adaptation of the digestive secretions to the character and digestive requirements of the food is not possible. There is a marked and important difference between eating a food that is a natural protein-starch combination and eating two foods, one a protein, the other starch.
When starches and proteins are eaten together, there is a fermentation and this results in fouling the whole digestive tract. Fermentation means irritation and poisoning. If starch is eaten without protein, the gastric (stomach) secretions will not be acid, or will be so weakly acid that they will not interfere with salivary digestion. In this case here will be no fermentation, except from other causes, such as overeating, hurried eating, other wrong combinations, eating when fatigued, worried, angry, fearful, grieved, etc., eating immediately before beginning work, eating when in pain, fever or when there is inflammation, etc. The causes of indigestion are legion.
* Never consume two concentrated proteins at the same meal.
Two concentrated proteins of different character and composition (such as nuts and cheese) should not be combined. Gastric acidity, type, strength and timing of secretions for various proteins are not uniform. Some people with impaired digestions find it necessary to limit themselves to only one variety of nuts/and or seeds at a sitting, but other people may find, upon experimentation, that two or three varieties of nuts or seeds may be used at the same meal, if desired.
Starch-starch* Eat but one concentrated starch at a meal.
This rule is probably more important as a means of avoiding the overeating of starches than as a means of avoiding bad combinations. But it is true that starch foods may differ greatly. If two different starches are eaten together in small quantities, this is thought to not cause problems.
Slightly starchy vegetables may be combined with more starchy vegetables (e.g. carrots with potatoes), but not with combination foods (starch/protein foods) such as grains and legumes.
Protein-fat* Do not consume fats with proteins.
Fat has an inhibiting influence on digestive secretion and lessen the amount and activity of pepsin and hydrochloric acid, necessary for the digestion of protein. The fat may lower the entire digestive tone more than 50 percent. Since most proteins already contain a good deal of fat, it would certainly be contraindicated to add more to the meal.
Most nuts contain about 10 percent to 20 percent protein, and about 45 percent to 70 percent fat. Avocados contain about 1.3 percent protein (Florida varieties) to about 2.2 percent or a little more (California varieties) and 11 percent to 17 percent fat. Most other protein foods are high in fat, including cheese, eggs and flesh foods. The only protein foods not high in fat are legumes, skim milk cheese and lean meat.
Fat-starch and fat-fruits* Do not consume fats with starch
Fats (oils and animal fats) also delay the digestion of other foods and, if used with starch, it will delay the passage of the starch from the stomach into the intestine. Fat not only inhibits the secretion of gastric juice—it also inhibits the physical actions of the stomach. Too much fat taken with a meal results in acid eructations and a burning sensation in the throat. When fats (avocados, olives or nuts) are eaten with green vegetables, preferably raw, the inhibiting effect of fats on gastric secretion is counteracted and digestion proceeds quite normally.
Eating avocados with salad enhances their digestion. The next best combination for these food is taking it with subacid or acid fruit. The fat in the food does not seem to interfere with the emptying time of the stomach and we have excellent results with this combination. The protein, which is about 2.1 to 2.5 percent, is not sufficient to interfere with the digestion of fruit. It is even better when lettuce leaves and celery are eaten with the fruit and avocado. By diluting the fats and the sugars with the lettuce, the emptying time of the stomach is not depressed.
Those who have weak stomachs with poor muscle tone would probably do better by taking avocado only with vegetable salads. If lettuce is taken with a sweet fresh fruit and avocado, even these digest well. It is probably best to never combine avocado with sweet dried fruit unless it is just a small amount of both eaten with a great deal of vegetables.
Since the avocado is low in protein, it may also be used with potatoes or other starch foods. Some people like to use avocado with the potato instead of using butter. However the best way to use avocado is with the salad.
Avocados should never be used with nuts, which are also high in fat, nor should they be used with melons.
Coconut is a starchy protein. It is sometimes used with sweet fruits. While coconut with sweet fruit is not an ideal combination, it seems to work out fairly well in most cases. Don’t use coconut with nuts or with acid or subacid fruits. You can make nondairy coconut carob ice cream.
Vegetables-proteins and starches* Salads and nonstarchy vegetables combine very well with proteins or starches.
Any nonstarchy vegetables may be combined with proteins or starch, except tomatoes, which should especially not be used with starches. The green leafy vegetables combine very well with most other foods. They are excellent food and should be used in the diet.
Lettuce and other green and nonstarchy vegetables leave the stomach with little change—they pass through the stomach rapidly unless delayed by oily dressings or foods that require a more thorough gastric digestion. Lettuce and celery are good combination with fruit because all of these foods require little gastric digestion.
However, even if these vegetables are held up in the stomach with other foods, as when using salad with nuts, there is no fermentation.
Eating a large salad of fresh raw vegetables (three or four varieties) daily is an excellent practice. Dr. Shelton says, “A large bowl of salad each day is required by everyone.”
Alfalfa sprouts may be combined as a green vegetable.
Other sprouts should properly be classified in the same category as the original seed, even though the sprouting process has somewhat lowered the protein and carbohydrate content.
Milk, yogurt and clabber* Milk is best taken alone.
This rule is included because it is one of Dr. Shelton’s food combining rules, and because it may be helpful to those still on a mixed diet. Hygienists do not drink milk. Adults do not need any kind of milk. Infants need their mother’s milk; if this is not available, they need a substitute.
Dr. Shelton says that the use of acid fruits or subacid fruit with milk does not cause any trouble and apparently does not conflict with its digestion. This would also apply to clabber (sour milk) or yogurt, which may be preferable to milk for adults. He also says that clabber is even a fair combination with dried sweet fruit.
Many adults (and some children) lack the enzymes lactase and rennin necessary for the digestion of milk. Lactase catalyzes the conversion of lactose (milk sugar) to the glucose and galactose which can be utilized by the body. Rennin is a milk-coagulating enzyme, which many adults no longer secrete.
This is also the reason that cheese is considered preferable to milk, although no dairy products are recommended for regular use.
None of these products are recommended. If any milk products are used, they should be raw (unpasteurized) and should not be used on a regular basis. Yogurt cultures, particularly, can inhibit the body’s own natural production of beneficial intestinal flora.
Water and juicesIt is important that starches be eaten dry, not moist. So, ideally you should eat steamed or baked potatoes dry rather than in potato soup. The eating of liquids with starches promotes the tendency to swallow moist starch without thorough mastication and insalivation processes that are particularly needed for the digestion of starches. Drinking liquids or eating watery foods softens the food artificially and may also cause you to eat more food than if you had eaten it dry. Drinking at meals can dilute the digestive juices and also prevents thorough mastication and insalivation of the food.
If thirsty, one may drink ten to twenty minutes before meals, one-half hour after a fruit meal, two hours after a vegetable or starch meal, and four hours after a protein meal. It is best to sip water, not gulp.
Never use large quantities of juiced foods and don’t use them as part of your regular food program. If you use juice occasionally, four to six ounces of vegetable juice may be taken twenty to thirty minutes before the evening meal at which a salad and, perhaps, some cooked food are eaten. Fruit juice— preferably fresh-made at home—may occasionally be used prior to a fruit meal. However, keep in mind that juices, either fruit or vegetable, are not beverages but fragmented foods.
The only time juices are indicated as part of a Hygienic program is when breaking a fast (though many people do very well in breaking a fast on whole fruit) or, very judiciously, as a temporary elimination diet
Coffee, tea and infusionsCoffee, tea and other such infusions can cause a premature emptying of the stomach and thus cause foods to leave the stomach before gastric digestion is complete. Tannic acid (in coffee and tea) inhibits starch digestion, as do drug acids.
- Do not eat Acid-Carbohydrate combinations.
- Do not eat Protein-Carbohydrate combinations.
- Do not eat Protein-Protein combinations.
- Do not eat Protein-Fat combinations.
- Use Fats sparingly in combination with other foods.
- Do not eat Acid-Protein combinations.
- Do not eat Sweet Fruit with Starch, Protein or Acid Fruit.
- Do not eat Starch-Starch combinations.
- Acid fruits combine well with Subacid fruits.
- Subacid fruits combine well with Sweet fruits.
- Do not eat Fruits with Vegetables except Lettuce and Celery.
- Eat Salads with most foods.
- Melons are best used alone.
- Milk, Yogurt, Clabber – eat them alone; ideally not at all.
Tip: On a practical note, it is very important adhering to “The Big Three” food combining guidelines - #2, 7 & 13 from the above list:
- Do not eat Protein-Carbohydrate Combinations.
- Do not eat Sweet Fruit with Starch, Protein or Acid Fruit.
- Eat Melon Alone
Sequence of EatingIt is true that all the food will be mixed in the stomach, but the so-called “Ideal Order of Eating” is helpful to some extent.
* Eat raw food before cooked food. Raw foods contain live enzymes, which influence digestive efficiency; cooking destroys all enzymes. Moreover, the consumption of raw foods stimulates gastric enzyme secretion, which is necessary to initiate good digestion. Besides, the more raw foods eaten as the first course, the less cooked foods will be eaten.
* Eat juicy foods before dry foods. During the process of digestion, hydrolysis occurs—that is, the combining of the food with liquid from the body’s reserve supply. Juicy foods contain some of their own liquid, which facilitates the initial processing of the food mixture. (Do not take water with dry foods as an alternative—this causes problems)
* Eat easy-to-digest foods before foods, that require a longer digestion time. The digestive process starts while the meal is being consumed, and the most liquid portion of the food mixture, the chyme, leaves the stomach at intervals. Thus, some of the easy-to-digest foods may be processed and leave the stomach before the end of the meal. Even if this does not occur, if the concentrated foods are eaten last, you may possibly eat less of them, which would be an advantage for many people, especially those who have a tendency to overeat of the concentrated proteins and starches.
An exception may advantageously be made in the case of eating salad alternately with nuts, rather than consecutively. Many people find that eating the salad along with the nuts actually aids digestion, and also eliminates the dry or thirsty feeling that sometimes follows the eating of nuts after the salad.
If you sometimes would like to eat fruit in combination with a mixed vegetable meal, the best way would be to eat the fruit first, and then, if possible, delay at least fifteen minutes before eating the other foods, starting with the salad.
As previously indicated, exceptions to this arbitrary “eating order” are not serious. After all, it does all go into the same stomach, and is quickly combined into a mobile mixture, the chyme.
Digestive Physiology and Food Combining, T.C.Fry
"Food Combining made Easy", Herbert M. Shelton