It is commonly
believed that the human stomach should be able to digest any number of
different foods at the same time. However, digestion is governed by
physiological chemistry. It is not what we eat that is crucial to our
health, but what we digest and assimilate.

Digestive enzymes
Digestive enzymes are secreted in very specific amounts and at very
specific times. Different food types require different digestive
secretions. Carbohydrate foods require carbohydrate-splitting enzymes,
whereas protein foods require protein splitting enzymes, etc. It is the
knowledge of the digestive process that has led many health practitioners
to promote efficient food combing, the rules of which are briefly
explained below:

1.

Carbohydrate foods and
acid foods should not be eaten at the same meal. Do not eat bread, rice or potatoes with lemons, limes, oranges,
grapefruits, pineapples, tomatoes or other sour fruits. This is because the
enzyme, ptyalin, acts only in an alkaline medium; it is destroyed even by
a mild acid! Fruit acids not only prevent carbohydrate digestion, but they
also produce a fermentation. Oxalic acid, for example, diluted to one part
in 10,000 completely arrests the action of ptyalin. And, there is enough
acetic acid in one teaspoon of wine vinegar to completely halt salivary
digestion. Dr Percy Howe of Harvard Medical School states: 

"Many people who cannot eat oranges at a meal derive great benefit
from eating them fifteen to thirty minutes before the meal". Herbert
Sheldon, author of ‘The science and fine art of food and nutrition’
reports: " I have put hundreds of patients , who have told me that
they could not eat oranges or grapefruit, upon a diet of these fruits and
they found that they could take them. Such people are in the habit of
taking these foods with a breakfast of cereal, with cream and sugar, egg
on toast, stewed prunes and coffee, or some similar meal."

Tomatoes should also never
be combined with starchy food as the combination of the various acids in
the tomato, which are intensified on cooking, are very much opposed to the
alkaline digestion of starches. They may be eaten with leafy vegetables
and fat foods.

What all this tends to mean
is that people who say they cannot eat oranges or grapefruit as it gives
them gas, could be blaming the fruit, when the problem may lie with the
escape of starches and the bodies release of pancreatic juice and
intestinal enzymes to break them down.

In cases where there is
hyperacidity of the stomach there is great difficulty digesting starches.
Fermentation and poisoning of the body occurs along with much discomfort.
This is because the digestion of carbohydrates (starches and sugars) and
of protein is so different, that when they are mixed in the stomach they
interfere with the digestion of each other. An acid process (gastric
digestion) and an alkaline process (salivary digestion) can not be carried
on at the same time in an ideal way in the stomach. Before long, they
cannot proceed at all , as the rising acidity of the stomach soon
completely stops carbohydrate digestion. The highest efficiency in
digestion demands that we eat in such a way as to offer the least
hindrance to the work of digestion.

2. Do not eat a
concentrated protein and a concentrated carbohydrate at the same meal.
This means do not eat nuts, meat, eggs, cheese, or other protein foods at
the same meal with bread, cereals, potatoes, sweet fruits. Cakes, etc. Candy and sugar greatly
inhibit the secretion of gastric juice and markedly delay digestion and if
consumed in large quantities can depress the stomach activity.

3.
Do not eat two
concentrated proteins at the same meal. Avoid nuts and meat, or eggs and
meat, cheese and nuts, cheese and eggs, meat and milk, or eggs and milk or
nuts at milk at the same meal. Milk, if taken at all, is best taken alone.
The reason for avoiding
eating these combinations is because each protein requires a specific
character and strength of digestive juice to be secreted. Eggs require
different timing in stomach secretions than do either meat or milk.

4. Do not eat fats with
proteins. This means do not use cream, butter, oil, etc with meat, eggs,
cheese, nuts, etc. Fat depresses the action of the gastric glands by
delaying the development of appetite juices and inhibiting the pouring out
of the proper gastric juices for meats, nuts, eggs or other protein. Fats
may lower the entire gastric tone more than fifty per cent.

5. Do not eat acid fruits
with proteins. This is to say, oranges, tomatoes, lemons, pineapples,
etc., should not be eaten with meat, eggs, cheese or nuts. Acid fruits
seriously hamper protein digestion and results in putrefaction. Milk and
orange juice, while by no means an indigestible combination, is far from a
good combination. Orange juice and eggs form an even worse combination.

6. Do not consume starch
and sugars together. Jellies, jams, fruit, butter, sugar, honey, syrups,
molasses, etc., on bread, cake, or at the same meal with cereals,
potatoes, etc., or sugar with cereal, will produce fermentation. The
practice of eating starches that have been disguised by sweets is also a
bad way to eat carbohydrates. If sugar is taken into the mouth it quickly
fills with saliva but no ptyalin is present which we know is essential for
starch digestion.

7. Eat but one concentrated
starch food at a meal. This rule is more important as a means of
overeating than as a means of avoiding a bad combination. While overeating
of starches may lead to fermentation, there is no certainty that the
combination of two starches will do so.

8. Do not consume melons
with any other foods. Watermelon, muskmelon, honeydew melon, cantaloupe
and other melons should always be eaten alone. This is possibly due to the
ease and speed in which melons decompose.

9. Milk is best taken alone
or let alone. Milk is the natural food of the mammalian young, each
species producing milk peculiarly and precisely adapted to the needs of
its young. It is the rule that the young take the milk alone, not in
combination with other foods. Milk does not digest in the stomach, but in
the duodenum, hence in the presence of milk the stomach does not respond
with its secretion. The use of acid fruits with milk does not cause any
trouble and apparently does not conflict with its digestion.

A suggested combination of
meals is included in the following plan of eating three meals a day :

Breakfast 
Fruit. Any
fruit in season may be used. It is suggested that not more than three
fruits be used at a meal, as, for example, grapes, well ripened bananas
and an apple. It is well to have an acid fruit breakfast one morning and a
sweet breakfast the next. In season breakfast may be made of melons. In
the winter months, one or two dried fruits such as figs, dates, raisins,
prunes, etc., may be substituted for the fresh fruit.

Lunch 

A
large raw vegetable salad of lettuce, celery, and one or two other raw
vegetables plus avocado and alfalfa sprouts or nut and seeds. As an
alternative, a vegetable salad (omitting tomatoes), one cooked green
vegetable and a starch.

Dinner 

A
large raw vegetable salad (if nuts or cottage cheese are to be used as the
protein, tomatoes may be used in this salad), two cooked non-starchy
vegetables and a protein.

Fat meats, sour apples,
beans, peanuts, peas, cereals, bread and jam, or hot cakes and honey or
syrup, are notoriously slow in digestion and are frequent sources of
discomfort and putrescent poisoning.

 If the body’s reserves
are carefully hoarded they will carry us well beyond the hundred year mark
with youthful enthusiasm and zest. Their depletion is one of the most
common calamities of modern life. The alkaloids and alcohols, with which
gastro-intestinal decomposition charges our bodies, rob us of our
reserves, greatly weaken our vital resistance and sooner or later produce
a state of physiological collapse.