Food is anything which, when taken into the body under proper conditions, is broken down and taken into the blood and utilized for building, repairing or the production of heat or energy.

There are various forms of foods, which can be divided into two classes: First, nitrogenous foods or proteins. Second, carbonaceous, foods, under which caption come the sugars, starches and fats. Salts and water are not usually classified as foods, though they should be, for life is impossible without either.

The chief proteins are: First, the albuminoids, which are represented by the albumin in eggs, the casein in milk and cheese, the myosin of muscle and the gluten of wheat. Second, the gelatinoids, which are represented by the ossein of bones, which can be made into glue, and the collogen of tendons. Third, nitrogen extractives, which are the chief ingredients in beef tea. They are easily removed from flesh by soaking it while raw in cold water. They are rich in flavor and are stimulating. They have absolutely no food value. Beef tea, and other related extracts, are not foods. They are stimulants. In truth they are of no value, and those who purchase such preparations pay a high price and get nothing in return.

The sugars and starches are grouped under the name of carbohydrates, which means that they are a combination of water and carbon. There are various forms of sugar. About 4 per cent of milk is milk sugar, which agrees better with the young than any other kind of sugar. It is not so soluble in water as the refined cane sugar, and therefore not so sweet, but it is fully as nourishing. Honey is a mixture of various kinds of sugars. Cane sugar is taken principally from sugar beets and sugar cane. There is no chemical difference between the products of canes and beets. Sugars can not be utilized by the blood until it has changed them into other forms of sugar.

The use of sugar is rapidly increasing. Several centuries ago it was used as a drug. It was doubtless as effective as a curing agent as our drugs are today. Until within the last sixty or seventy years it has not been used as a staple food. Now it is one of our chief foods. Not so very long ago but ten pounds of sugar per capita were used annually, but now we are consuming about ninety pounds each annually, that is, about four ounces per day. Many people look upon sugar as a flavoring, which it is in a measure, but it is also one of our most concentrated foods.

That this great consumption of sugar is harmful there is no doubt. Physicians who practiced when the use of sugar was increasing very rapidly called attention to the increasing decay of teeth. Sugar, as it appears upon the table is an unsatisfied compound. It does not appear in concentrated form in nature, but mixed with vegetable and mineral matters, and when the pure sugar is put into solution it seeks these matters. It is especially hungry for calcium and will therefore rob the bones, the teeth and the blood of this important salt, if it can not be had otherwise. The most noticeable effect is the decay of the teeth.

I have read considerable literature of late blaming sugar for producing many diseases, among them tuberculosis and cancer. Improper feeding is the chief cause of these diseases, but to blame sugar for all ills of that kind is far from arriving at the truth. Cancer and tuberculosis killed vast numbers of people before sugar was used as a staple. If we wish to get at the root of any trouble, it is necessary for us to bury our prejudices and be broad minded.

People who eat much sugar should also partake liberally of fresh raw fruits and vegetables, in order to supply the salts in which sugar is deficient. Lump sugar is practically pure, and therefore a poorer article of diet than any other form of sugar, for man can not live on carbon without salts.

Grape sugar and fruit sugar are the same chemically. Another name for them is dextrose, and in the form of dextrose sugar is ready to be taken up by the blood.

Children like sweets, but it is just as easy to give them the sweet fruits, such as good figs, dates and raisins, as it is to give them commercial sugar and candy, and it is much better for their health. Children who get used to the sweet fruits do not care very much for candies. The sugar in these fruits is not concentrated enough to be an irritant and it contains the salts needed by the body. Hence it does not rob the body of any of its necessary constituents. Because the fruit sugar, taken in fruit form, is not so concentrated and irritating as the common sugar, the child is satisfied with less.

Sugar is an irritant of the mucous membrane and therefore stimulates the appetite. This is true only when it is taken in excess in its artificial form, and it does not matter whether it is sugar, jelly or jam. For this reason jellies and jams should be used sparingly, because it is not necessary to stimulate the appetite. Those who resort to stimulation overeat. When much sugar is taken, it not only irritates the stomach, but it even inflames this organ.

Sugar is a preservative, and like all other preservatives it delays digestion, if taken in great quantities, and four ounces per day make a great quantity. The digestive organs rebel if they are given as much of sugar as they will tolerate of starch. When taken in excess sugar ferments easily, producing much gas, which is followed by serious results.

Sugar is changed into forms less sweet by acids and heat. The ferment invertin also acts upon sugars.

Sugar is a valuable food, but we are abusing it, and therefore it is doing us physical harm. The quantity should be reduced, and families who are using four ounces per person per day, as statistics indicate that most are doing, should reduce the intake to about one-third of this amount. It would be well to take as much of the sugar as possible in the form of sweet fruits.

It is a fact that sugar is easy to digest and that one can soon get energy from it, but feeding is not merely a question of giving digestible aliments, but a question of using foods that are beneficial in the long run. The moderate use of this food is all right, but excess is always bad. Starches need more change than sugars before they can be absorbed by the blood, but they give better results. Chemically there is but small difference between starch and sugar. The starch must be changed into dextrose, a form of sugar, before it can be utilized by the body.

The human body contains a small amount of a substance called glycogen, which is an animal starch or sugar. This glycogen is burned. Sugar is a force food. It combines with oxygen and gives heat and energy. The waste product is carbonic acid gas, which is carried by the blood to the lungs and then exhaled.

Honey and maple sugar are good foods, but overconsumption is harmful.

Sugar eating is largely a habit. Because the sugar has so much of the life and so many of the necessary salts removed in its refinement it is a good food only when taken in small quantities. Nature demands of us that we do not get too refined in our habits, for excessive refinement is followed by decay. It is easy to overcome the tendency to overeat of sugar.

Some spoil the most delicious watermelon by heaping sugar or salt, or both, upon it. In this way the flavor is lost. There is not a raw fruit on the market which is as finely flavored after it has been sugared as it was before. True, those who have ruined their sense of taste object to the tartness and natural acidity of various foods, but they are not judges and can not be until they have regained a normal taste, which can only be done by living on natural foods for a while.

Fats are obtained most plentifully from nuts, legumes, dairy products and animal foods. They are the most concentrated of all foods, yielding over twice the amount of heat or energy that we can obtain from the same weight of pure sugar, starch or protein. Many who think they are moderate eaters consume enough butter to put them in the glutton class.

Salts are present in all natural foods of which we partake.

Water is indispensable, for the body has to have fluids in order to perform its functions.

Foods are burned in the body. They are valuable in proportion to the completeness with which they are digested and assimilated and the ease with which this process is accomplished. It takes energy to digest food and if the food is very indigestible it takes too much energy.

The following remarks on digestibility are according to the best knowledge we have on the subject:

As a general rule, the protein of meat and fish is more completely and more quickly digested than the protein in vegetable foods. The reason is that the vegetable protein is found in cells which are protected by the indigestible cellulose which covers each cell. This covering is not always broken and then the digestive juices are practically powerless.

The legumes, which are rich in protein, are comparatively hard to digest. If properly prepared and eaten, they give little or no trouble, but they are generally cooked soft and the mastication is slighted. The result is fermentation. Beans, peas and lentils should be very well chewed, and eaten in moderation, for they are rich both in starch and protein.

Nuts are as a rule not as completely digested as meats and animal fats, and the principal reason is that they are eaten too rapidly and masticated too little. Nuts properly masticated, taken in correct combinations and amounts agree very well. It is not necessary, as many believe, to salt them in order to prevent indigestion.

In the following pages will be found a number of diet tables, giving compositions and fuel values of various foods which have been grouped for the sake of convenience, for the foods in each group are quite similar. These tables are not complete, for to list every food would take too much space. I have simply selected a representative list from the various classes of foods. Under flesh are given fish, meats and eggs. Under succulent vegetables are given both root and top vegetables, because of their similarity. Nuts, cereals, legumes, tubers and fruits are each grouped because it is easy to gain an understanding of them in this way. Milk is given a rather long chapter of its own because of its great importance in the morning of life.

Allow me to repeat that it is impossible to figure out the calories in a given amount of food and then give enough food to furnish so many calories and thus obtain good results. I have already given the key to the amount of food to eat, and it is the only kind of key that works well. However, it is very helpful to have a knowledge of food values.

The calorie is the unit of heat, and heat is convertible into energy. A calorie is the heat required to raise the temperature of one kilogram of water one degree C. To translate into common terms, it is the heat required to raise one pound of water four degrees F.

One pound of protein produces 1,860 calories.
One pound of sugar produces 1,860 calories.
One pound of starch produces 1,860 calories.
One pound of oil or fat produces 4,220 calories.

For the scientific facts regarding foods I have consulted various works, especially the following: Diet and Dietetics, by Gauthier; Foods, by Tibbles; Food Inspection and Analyses, by Leach; Foods and their Adulteration, by Wiley; Commercial Organic Analysis, by Allan. However, I am most indebted to the numerous bulletins issued by the U. S. Department of Agriculture. All who make a study of foods and their value owe a great debt to W. O. Atwater and Chas. D. Wood, who have worked so long and faithfully to increase our knowledge regarding foods.

As we consider the various groups of foods, directions are given for the best way of cooking, but no fancy cooking is considered. Those who wish fancy, indigestible dishes should consult the popular cook books.

The women have it in their power to raise the health standard fifty to one hundred per cent by cooking for health instead of catering to spoiled palates, and by learning to combine foods more sensibly than they have in the past. The art of cooking has made its appeal almost entirely to the palate. This art is not on as high level as the science of cooking, which gives foods that build healthy bodies. The right way of cooking is simpler, quicker and easier than the conventional method, and gives food that is superior in flavor. After the normal taste has been ruined, it takes a few months to acquire a natural taste again so that good foods will be enjoyed.