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In Theory...

Trophology is the study of correct food-combining, that is, the art of knowing which foods go best with which others. Foods can be grouped according to their main constituents as follows:

The process of digestion has nine basic rules which describe combinations to avoid:

  1. Carbohydrate + Carbohydrate
  2. Carbohydrate + Acid Fruit
  3. Carbohydrate + Protein
  4. Carbohydrate + Sugar
  5. Protein + Acid Fruit
  6. Protein + Protein
  7. Protein + Fat
  8. Melon + any other food
  9. Milk + any other food

Proteins are digested by the enzyme pepsin in the stomach, which only works in the presence of hydrochloric acid (HCl). (Note this is different from the acid in acid fruits, which impede protein digestion.) Different concentrated proteins require secretions of very different digestive juices, so one should only eat one kind of protein (and likewise only one starch) at a time. However, since most foods contain small amounts of protein, we ignore it in combinations, the rules for combining foods applying only to the concentrated starches, sugars, fats and proteins.

Starches, on the other hand, require an alkali medium and the amylase in saliva which contains ptyalin, an enzyme which breaks down starch into maltose. The process continues in the small intestine, where more amylase further breaks down the maltose into simple glucose, fructose and galactose. These are absorbed into the bloodstream, and taken to the liver, which dispenses the energy to whatever cells in the body need it. If there is no immediate requirement, the glucose will be converted to glycogen and stored in the liver, or into fat to be stored in adipose tissue.

So consuming proteins and starches together will result in each being impeded by the other. Similarly, the eating of sugars and acid fruits impede the action of ptyalin and pepsin, reducing the secretion of saliva, and delaying digestion. If insufficient amylase is present in the mouth (due to insufficient chewing, or too much sugar), any starches will not be digested at all in the stomach, instead clogging up the works until amylase in the small intestine can get to work on it.

Fats impede the secretion of digestive juices, and reduce the amount of pepsin and hydrochloric acid, so they should be avoided or used sparingly with protein-rich foods.

Vegetables and salads combine well with all food types.

Acid fruits clash with most things, so are best eaten on their own; melons also, a special case, which should never be combined with other foods. Sub-acid fruits are easier to mix with other types in moderation, but all fruits are digested not in the stomach but the intestine, so will just slow things down (and ferment) until they get there. This is why a purely fruit diet is so beneficial to health (especially when one is ill), there being no starches or proteins to impede the fruits which pass quickly through the stomach to the intestine.

This may all sound contrary to our 'conventional' habits, until one realises that the sandwich and the hamburger are modern inventions. However, consider a sliced-lemon sandwich, or melon with millet, or pineapple with almonds, or pasta with potatoes and tortillas, and see how appetising they sound; instinctively upsetting no doubt, although we think nothing of pouring lemon juice on salad to accompany (destroy) our crusty baguette. Milk is best taken alone or left alone.

In the ancient Hebrew writing (Exodus) we read: "And Moses said... Jehovah shall give you in the evening, flesh to eat, and in the morning, bread to the full,... and Jehovah spake unto Moses saying... at evening ye shall eat flesh, and in the morning ye shall be filled with bread.' This statement from Exodus is one of the earliest records of the practice of eating proteins and carbohydrates at separate meals.

[...] there is evidence that it was also a practice among the Greeks. In an article in Your Physique, Sept. 1946, David P. Willoughby, a leading authority on physical education, tells us that "the regular diet of pugilists and wrestlers of antiquity 'consisted mainly of meat -- preferably beef, pork, or kid -- and bread. Meat and bread were not to be eaten at the same meal.'" Here is a practice of keeping proteins and carbohydrates apart in eating that has a sound physiological basis.

[...] Please note that carnivores in nature never mix carbohydrates with their meat.

- Herbert M. Shelton in Chapter XXVI of Orthotrophy (1935)

In Practice...

I tried eating separate meals of proteins and carbohydrates for a while, but found it quite hard to maintain a satisfying diet this way, probably due to years of ingrained eating habits. (Having written this article I shall certainly try some more experiments now I am a bit wiser.) Studies on young children, however, show that given the choice of a wide range of foods of all kinds, at first they try a bit of everything, to find what they like.

Children seldom consumed more than 2 or 3 of the 10-12 food items presented at each meal. They would often choose the same food for several meals (to the exclusion of other foods), then abandon that food for others.

- Davis, C.M. (1928) - American Journal of Diseases of Children, 36(4), 650-679

Eventually they settled into a pattern of eating only one or two foods at a time, say lots of beetroot, or lots of fish, and ignored sweets in favour of slow-release carbohydrates such as potatoes and rice. If one thinks about our prehistoric hunter-gatherer ancestors, they would probably eat whatever food they found, be it grains or fish or a handful of nuts or fruits.

I think it is important to not get too obsessed with finding the perfect diet straight away, because our needs change throughout our lives and depend on age, climate, exercise and other factors. It takes a lot of experiential study to find what suits you and what you enjoy. Bear these trophological issues in mind, but don't feel constrained by them. The most important thing is to eat a balanced diet which includes plenty of slow-release carbohydrates from whole-grains, protein from pulses and seeds, fibre from fresh fruit and veg, and little or no sugared or processed food. If you're wanting to lose weight, then the ideas presented here may be helpful, but really the best way to lose weight is to get plenty of exercise and eat a healthy, balanced diet, as:

Promoting weight loss through dietary restriction and behavior modification rarely succeeds, often results in weight cycling (repeated bouts of weight loss and regain) with the potential for serious physical and psychological health risks and contributes to a growing epidemic of dangerous eating disorders.

- Jonathan Isaac Robison, PhD MS, Alternative Health Practitioner, Vol. 5, No. 1, Spring 1999

A diet rich in fresh fruits and vegetables and plenty of fibre seems to help protect against bowel cancer and there is evidence that a diet containing much meat may increase the risk.

Good luck in your quest, and I hope this helps.

© copyright Malcolm Smith 2002-04-10 - last updated 2004-02-01 - links verified 2004-02-01