The Rationale Of Food Combining
 By: Dennis Nelson

The principles of food combining were first explained in the earlier part of the
20th century by Dr. John Tilden, M.D., author of
Toxemia Explained, and Dr.
William Howard Hay, M.D.  

Their work was followed by that of Dr. Herbert Shelton and is continuing with
the doctors and teachers of the Natural Hygiene movement.

This is not to imply that those people
"laid down the law" about how we
should eat, but rather that they observed how the human body works
optimally in carrying out the processes of digestion.  They found that nature's
way demands simplicity, and any alterations of this plan will be met with less
than ideal consequences.  

It has been observed that animals in nature eat very simply and combine their
food minimally.  Carnivorous animals eat their meal alone, without any
carbohydrate or acid foods.  Birds and squirrels have also been observed to
eat one type of food at a time.  Certainly no animal in nature would at any one
time eat the variety of foods that many humans are accustomed to eating at a
conventional meal.  

The basis for food combining is a logical application of the chemistry and
physiology of digestion, with special consideration given to the limitations of
our digestive juices and enzymes.  The practical application of this knowledge
has given us the rules of food combining, which we may use to ensure a
greater degree of digestive efficiency.  

In relating this concept to nutrition, we should realize that the nourishment
our body receives is dependent on what we can digest and assimilate.  That
which is not digested only wastes the body's energy in passing it through the
alimentary canal.  What is worse, the undigested food becomes soil for
bacteria to feed upon, resulting in putrefaction and fermentation, which
irritates and poisons our tissues.  This is a primary contributing factor in the
causation of disease.  

This is not to say that applying the principles of food combining will always
lead to good digestion, as there are other factors, which reduce our digestive
capabilities, e.g., overeating and eating under stressful conditions.  

Some of these include: fatigue; preceding or following strenuous exercise;
during a fever or when there is severe inflammation; and while experiencing
strong emotions.  All of these conditions hinder digestion and predispose to
bacterial decomposition of food.  

In addition, the use of condiments, (especially salt), vinegar, alcohol, coffee or
tea during a meal retards digestion considerably.  All of these circumstances
must be considered if one desires good digestion, and, consequently, a well-
nourished body.  

That people suffer greatly from indigestion is evidenced by the fact that
billions of dollars are spent yearly on over-the-counter medicines in the U.S.
alone, to suppress the pains and discomforts due to conventional eating and
living habits.  

Diseases of the stomach, intestines, colon, and rectum are on the increase;
conventional treatment with drugs and surgery does not remove their
underlying causes.  

We need to adopt a saner plan of living that includes sound nutritional
principles, if we are ever to remedy this situation.  Simple meals of compatible
combinations are a necessity for good digestion.  

Dr. Shelton says in his book
Food Combining Made Easy:

"As all physiologists are agreed that the character of the digestive juice
secreted corresponds with the character of the food to be digested and that
each food calls for its own specific modification of the digestive juice, it follows
as the night the day, that complex mixtures of food greatly impair the efficiency
of digestion.  Simple meals will prove to be more easily digested, hence more

The wonderful thing about the food combining concept is that anyone, no
matter what their dietary preference, may benefit from the application of these
rules to their particular diet.  Whether you subsist on a vegetarian diet or one
that includes animal foods need not be a concern in food combining

The digestive system works fundamentally the same for all humans, both
chemically and physiologically.  The idea that each one of us has individual
needs and capacities is true to a certain extent, but this does not nullify the
physiological limitations of the human organism.  

To quote Dr. Shelton again:

"There are great numbers of people who will object lo these simple rules on
the ground that their own experiences have revealed that it is safe for them to
violate each and every one of these rules.  The rules, they will say, may be
applicable to some people, but not to them.  

The individual, rejecting the existence of a general law as the basis of
physiology and digestion in diet, in health and disease, and holding that what is
most valuable to one person may not be helpful to another – that 'one man's
meat is another man's poison' – and that what is best for each individual may
be determined only by observation of each person's idiosyncrasies will,
perhaps, find it impossible to accept the truth of any plan of living that does not
meet with the approval of his/her habits and prejudices.

If we accept the obvious fact that a general law underlies physiology and
biology and that all are subject to this law, it becomes easy to understand that
hard and fast rules may be established that will fit all human beings.  
Physiology is not as chaotic and unlawful as some people seem to think.  

I frequently get another objection to any effort to regulate the diet and eating
practices according to any law of life.  It runs this way: 'Diet is not all of life.  
Other things are also important.'  Nobody stresses this fact as emphatically as
does the Hygienist; but the objection is not raised by those who wish to
emphasize the importance of the factors of life.  It is made by those who desire
to find a reason to disregard all the sane rules of eating and living. "  

Digestion of Foods

Digestion is the term that applies to the processes by which the complex
materials of food are broken down into simpler substances in preparation for
their subsequent entrance into the bloodstream.  

For example, proteins are broken down into amino acids; carbohydrates,
composed of starches and sugars, are converted into simple sugars; and fats
are broken down into fatty acids.  These are the simple substances, which the
body can use to build new tissue.  Let us now discuss this process and how it

The human digestive tract may be divided into three cavities: the mouth, the
stomach, and the small intestine.  Each of these cavities contains its own
distinct digestive secretions with which to carry on its own specific work of
digestion.  In each of these three stages, the work carried on at one stage
prepares the food for the digestive work done at the next.  

For purposes of this article, we need only concern ourselves with first two
stages of the digestive process, that of salivary and gastric digestion.  
However, it must be understood that the efficiency of their work will determine
the efficiency of digestion that is subsequently conducted in the intestine.  

When food enters the mouth, the mechanical process of mastication along
with the chemical process of insalivation initiate the digestive process.  The
taste buds are excited and these tiny nerve endings send signals to the brain
to determine the type of food ingested.  

Immediately, specific juices are secreted, and an environment is created for
the efficient digestion of that particular food.  If this contains starch, then a
specific enzyme called
“salivary amylase” (ptyalin) will also be secreted in the
saliva.  However, this enzyme acts only upon starches and will not be
secreted if the food does not contain starch.  

After leaving the mouth, the food passes down the esophagus and into the
stomach, where the digestive process continues.  Here we find gastric juice
containing primarily hydrochloric acid and digestive enzymes.  The pH of this
gastric juice is variable, ranging from highly acidic to a mild acid or nearly
neutral medium, depending on the type of food eaten.  This variable range is
secured by the degree of concentration of the hydrochloric acid.  

Also present in the gastric juice are three primary enzymes: pepsin, which
acts upon proteins; gastric lipase, which acts upon fats; and rennin, which
acts upon milk proteins.  This third enzyme is present in sufficient quantities
only in the gastric juice of infants.  

When the child has a full set of teeth, the secretion of rennin begins to
diminish.  This phenomenon indicates the time for weaning and feeding solid
food.  There is no physiological need for milk from this time forth.  

The important fact to understand here is that each enzyme can act only upon
one class of food.  For instance, the enzyme salivary amylase, which acts
upon starches, cannot act upon protein or fat.  In fact, enzymatic action is so
specific that each one of the different forms of complex sugars, such as
maltose or lactose, requires its own specific enzyme for digestion.  

An additional consideration is the fluid medium in which the digestive process
takes place during the gastric phase.  In the case of starches, salivary
amylase requires an alkaline medium in which to continue its work and will be
destroyed by a highly acid environment.  

This is also true of fats, whereby the enzyme gastric lipase and its action
upon fats is inhibited by a highly acid medium in the stomach.  However, in
the case of proteins we have the opposite situation; they require a highly acid
environment for the enzymatic activity of pepsin to take place.  This is created
by a sufficient outpouring of hydrochloric acid into the gastric juice.  

Now as previously stated, there are three stages of the digestive process.  
Each one of these stages requires the action of different enzymes, and the
efficiency of their work is determined by the digestive efficiency of the
preceding stage. It is a sequential operation.  

For example, if pepsin, the enzyme secreted in the stomach during protein
digestion, has not converted the proteins into peptones, it follows that
erepsin, the enzyme secreted in the intestine, will not be able to carry on the
final stage of protein digestion, that of converting the peptones into amino
acids.  The work of each enzyme is designed specifically for the stage of its

So, if there is to be efficient digestion of a food, the limitations of each stage of
the digestive process must be respected.  This requires that a food be eaten
by itself or in combination with other foods that will not interfere with the
distinct activity of different enzymes.  

When two foods are eaten that require opposite conditions for their digestion,
the secretions will clash with each other and digestion of both foods will be
limited or even suspended.  

Another observation concerning the efficient digestion of various foods
pertains to the emptying time of the stomach into the intestine.  Fruits, when
eaten alone as a meal, will remain in the stomach from ten minutes to an hour.  

However, when concentrated starches are eaten, their digestive time in the
stomach takes from two to three hours.  

In the case of concentrated proteins, the digestive time required in the
stomach is about four hours.  In fact, some foods may require five or six hours
to complete gastric digestion, as in the case of Legumes or grains.

The point I wish lo make here is this: If foods are eaten together which require
different time periods for gastric digestion, then we create a situation in which
a food requiring the shorter time is held up in the stomach awaiting the more
lengthy digestive time required by the other food.  When this occurs, as when
fruit or other sugars are eaten with protein, for example, the sugars ferment
and nutrition is impaired.  

Thus, with these considerations in mind, we may realize that we have the
possibility of creating two distinct experiences when taking food.  In the case
of carbohydrates, during digestion they are broken down into simple sugars
called monosaccharides, which the body can make use of to provide us with

However, if carbohydrates undergo fermentation, they are broken down into
carbon dioxide, acetic acid, lactic acid, alcohol, and water; all, with the
exception of the last, are poisonous substances.  

In the case of proteins, during digestion they are broken down into amino
acids; however, when putrefaction occurs, they are broken down into a
variety of ptomaines, leucomaines, and other poisons.

This is true with all other food components: enzymatic digestion of foods
prepares them for the nutritive needs of the body, whereas bacterial
decomposition of foods makes them unfit for its needs, poisoning it with the
products of fermentation and/or putrefaction.  

The responsibility for harmonious digestion rests with us.  Failure to observe
digestive requirements results in subsequent pathology of mild to acute

By: Dennis Nelson
From: The Natural Hygiene Life Science

Article: The Rationale of Food Combining