Carbonaceous Foodstuffs
The carbonaceous foods are those used by the body for heat and energy and are so named because they contain a large proportion of carbon,—heat producing element. It is the carbon in wood, which, uniting with oxygen, produces heat and light.
The carbonaceous foods are all composed of carbon, hydrogen, and oxygen, the difference being in the different proportions in which these elements are combined.
They are divided into two classes, Fats and Carbohydrates. The carbohydratesembrace the sugars and starches and include such substances as the starches of vegetables and grains (notably corn, rice, wheat, and the root vegetables), and the sugar of milk, of fruits, vegetables, and the sap of trees. Their chief office is to create energy. They are almost entirely absent from meat and eggs, the animal having converted them into fats.
Carbohydrates are easily digested.
Fat
Fat is the most concentrated form of fuel and is readily oxidized. It is almost pure carbon, hence less chemical work is required to convert it into fuel, but more oxygen is needed. A pound of fat has about three times as much fuel value as a pound of wheat flour, which consists largely of starch.
Fat forms about fifteen per cent of the weight of the normal body, and it has about twice the fuel value of carbohydrates.
Carbohydrates and fats are each composed of carbon, hydrogen, and oxygen, the difference being that there is less oxygen in fat, hence, more oxygen from the air is required for combustion of fat than for carbohydrates. One pound of starch requires one and one-fifth pounds of oxygen for perfect combustion, while onepound of suet requires three pounds of oxygen. For this reason the Eskimo, who depends largely upon the fats for body heat and energy, must have plenty of fresh air. One ounce of fat yields two and one-half times as much energy as an ounce of sugar or starch.
If sufficient fat is not consumed, or is not formed from the carbohydrates (starches and sugars), a certain portion of the protein of the body is converted into fat and used in energy. When the food supply is short, or much energy is called for, the surplus supply of carbohydrates is first used, and, if the carbohydrates are not sufficient, the proteins are used. Of the proteins, the gelatinoids are used first, and next the albuminoids, or tissue builders. If the demand, either in mental or physical energy, exceeds the daily supply for a length of time, the body becomes lean.
In warm weather little fat is needed for fuel and nature provides fresh, green vegetables to replace the root vegetables of the winter, which, consisting largely of starches and sugars, are readily converted into heat. In cold weather, especially in high altitudes or latitudes, more fuel foods are required to keep the body warm and more fat is eaten in winter.
Those who store up an abundance of fat suffer most from a rise in temperature, because combustion not only creates heat, but heat also aids combustion.
Fats are not digested in the stomach. The connective tissue about the fat is digested here, and the fat is passed on into the small intestine, where it is acted upon by the carbonates and by lipase, one of the enzymes of the intestinal juices. These first change the fat into an emulsion and then into a form of soap and glycerine. In this saponified form, it is in condition to be absorbed into the circulation and carried out to the tissues, where it is assimilated and used in energy; a similar chemical change is produced in the conversion of oil into soap.
Common examples of fats are butter, cream, the fat of meats and of nuts, and the oil of grains and seeds,—notably the cocoanut, olive, and, of the grains, oatmeal.
The fact that more oxygen is required for combustion of fat than of starches and sugars is an important item for those who wish to call upon the fats stored within the body for daily heat and energy and thus reduce in weight. If sufficient starches, sugars, and fats are not consumed in thefood to supply the daily heat and energy released by exercise, the body calls upon the sugars and starches temporarily stored up and, when these have been consumed, upon the reserve of fat. If much fat is consumed in the daily food this fat in the blood will be oxidized before the fat stored about the muscular tissue. The scientific reduction of weight, therefore, lies in the regulation of the supply of starches, sugars, and fats consumed, and, the oxidation of more of these substances through an increase in the daily exercise. Deep breathing of pure air should accompany all exercises, to supply sufficient oxygen for combustion, or oxidation.
Manual laborers require more fat for energy than do people whose habits are sedentary. School children, or children who play hard, should have sufficient fat, and where fats are withheld, sugar should be freely supplied.
The supply of fat stored in the body depends upon the quantity consumed with the food, upon the quantity used up in heat and energy, in muscular exercise, or in mental force. The quantity thus consumed depends somewhat upon the condition of the nerves. If the nerves are weak, they do not properly direct digestion andassimilation and less fat is consumed in the digestive and assimilative processes.
Butter and Cream.The fat present in milk depends, of course, upon the quality of the milk. There is as much butter fat in a glass of fresh Jersey milk as in a glass of cream, which has been separated, by machinery, from the milk of some other cows. The cream from some Jersey cows is almost all butter. Skimmed milk contains very little fat. If milk is drunk by the adult, as a means of storing up more fat within the body, the cream should be stirred into it.
The Fat of Meatshould be thoroughly cooked and cooked with moisture. All meats in the process of baking or frying should be covered, in order to retain the moisture. To make fat easily digestible it should be well masticated.
Bacon, if fully immersed in its own grease, in the process of frying, is a common source of fat and is easily digested.
Cod Liver Oilfrom the liver of the codfish, is more easily absorbed and assimilated than any other fat. The odor is not pleasant and a little lemon juice, salt, baking soda, or any substance for pungency and flavor, may be added to make it palatable. The pure oil taken in this way isperhaps preferable to the prepared emulsions. One has the advantage, at least, of knowing what he is taking.
Olive Oilis crushed from ripe olives. It is often used where cod liver oil is prescribed, because more palatable. Cotton seed oil is often substituted or mixed with the cheaper grades of olive oil. It is wholesome, if fresh, but has not the pleasing flavor of the olive.
Many take olive oil for the purpose of rounding out the figure with fat. If the system will assimilate fat, taken in quantities, the fat may be stored up, but, as a rule, one is underweight because of a failure to assimilate the regular diet and the overloading with fat would not cause a better assimilation.
Olive oil in moderation is a good food where much heat and energy are expended, but if ones occupation is sedentary, much fat is not required.
Nut Oilsare good, but, with the exception of peanut butter, are not often used.
Sugar
The sugars are cane and beet sugar, maple sugar, and glucose.
All sugars are carbohydrates,—carbon, hydrogen, and oxygen,—the oxygen and hydrogen being in the same proportions asin water, (two atoms of hydrogen and one of oxygen), the difference is that the carbon is missing from the water.
Sugar is said to consist of about ninety-five per cent nutritive value.
Glucoseis made by converting the starch in corn into sugar. It is pure, wholesome, and cheap, and, for this reason, it is often used to dilute other sugars. It is not as sweet as other sugars, and it ferments more readily. Many of the syrups on the market are made from it.
The common, granulated sugars are made from sugar cane or beets; beet sugar is becoming more generally used.
Brown sugar is granulated sugar in the early stages of refinement.
Maple sugar is obtained by boiling down the sap of the maple tree. It is often adulterated with other sugars or with glucose, because they are cheaper. This adulteration does not make it unwholesome, but when mixed with these it loses its distinct, maple taste and is more mild.
Before sugar can be used by the human system, it is changed into grape sugar, or dextrose, (another form of sugar) by a ferment in the small intestine called lactose. Milk sugar needs less chemical changethan other sugars and is taken almost at once into the circulation.
When an excess of sugar is consumed, it is stored within the body as glycogen, until required.
Sugar is perhaps a better food than starch, because less force is required for its digestion and it is easily assimilated, being more readily converted into dextrose than are starches. Moreover it furnishes the needed heat and energy to organisms that have no power to digest starch. Milk sugar is a part of the natural food for the infant, because the infant has not developed the ferment necessary for starch digestion.
Sugar may be oxidized within a few minutes after eating, and, for this reason, it is eaten by those who require to use an undue amount of muscular strength. It yields heat and energy within thirty minutes after eating and, in times of great exertion or exhausting labor, the rapidity with which it is assimilated gives it advantage over starch. Used in limited quantities, therefore, according to the muscular or brain power exercised, sugar is one of the best foods for the production of energy. Where much sugar is eaten less starch is required.
It is also said to prevent fatigue, a man being able to do seventy-five per cent more muscular work with less fatigue after consuming about seventeen and one-half ounces of sugar dissolved in pure water.
It might be inferred from the above, that starches could be discarded and replaced by sugars, but a small quantity of sugar soon surfeits the appetite and if the foods were confined to those with a surplus of sugars, sufficient food would not be eaten for the needs of the body. This lack of appetite, occasioned by an excess of sugars, is due, partly, to the fact that the gastric juice is not secreted as freely when there is much sugar in the stomach.
Because of the slower secretion of gastric juice and the surfeit of the appetite, sweetened foods are not used at the beginning of a meal, and, while a moderate amount of sugar is desirable, a surfeit is to be deplored.
While sugar is not converted into fat, it is so readily oxidized and thus supplies heat and energy so promptly that the starches and fats are not called upon until the latent energy in the sugar is used. Those who wish to reduce in flesh should eat it sparingly that the starches and fats may be called upon to furnish energy, butsugar should be as freely used as the system can handle it, by those who wish to build up in flesh.
Broadly speaking, about one-fourth of a pound of sugar, daily, in connection with other foods, is well utilized by the system, the quantity depending upon whether one leads an active or a sedentary life.
Candy is often made from glucose instead of molasses or cane sugar, and while glucose is wholesome, it undergoes fermentation readily. Much candy, unless one is actively exercising, tends to indigestion.
The desire of the child for sweets is a natural one, because it uses so much energy, and sugar supplies this energy with less effort of the digestive system. When the child begins to eat more solid foods, if sugar is used in abundance for sweetening, it is no longer attracted by the mild sweetness of fresh milk, and it is well to cut down the allowance of sugar, when the child turns against milk, in the hope of restoring the taste for this valuable food. Many of the best authorities state that the child, up to its third year, should never be allowed to taste sweets, in order that the appetite may not be perverted from the natural sweets of milk.
Sugar is better supplied the child in a lump or in home-made candy, rather than in the sweetening of porridge, oatmeal, or bread and milk, etc.
Sweet fruits, fully ripened, contain much sugar and should be freely given to the child. The natural flavor of fruits and grains is very largely destroyed by sugar, which is used too freely on many articles of diet.
Most vegetables and fruits contain sugar,—indeed sugar is the only nutriment in many fruits. The sweet taste in all fruits and vegetables is due to its presence. Sweet potatoes, beets, carrots, parsnips, turnips, grapes, figs, and dates are especially rich in sugar and when these are furnished with a meal, in any appreciable quantity, the starches should be restricted—notably bread, potatoes and rice.
Harvesters, road-makers and others, who do hard work in the open air, can consume large quantities of sugar in pie, pastry, etc., which are difficult to digest, while one who lives an indoor life, should refrain from an undue indulgence in these.
For one who is undernourished, sugar is a desirable food, if the starch be diminished in proportion as the amount of sugar is increased; but the inclination in sweeteningfoods is to take more starch than the system requires, since it is the carbohydrate foods which are ordinarily sweetened,—not the proteins.
On account of the latent heat and energy, sugars are more desirable in cold weather than in warm. Nature supplies them more abundantly in root vegetables for this season. More puddings and heavier desserts are eaten in winter.
Starch
Starch is one of the most important carbohydrates used for nutrition. It is formed by the chemical action produced by the sun’s rays upon the cells of living plants, from the carbon-dioxid and water in the air and in the soil.
Corn starch, sago, tapioca, and arrowroot are practically pure starch. Cornstarch is from young maturing corn; tapioca is from the meal of a tropical plant, cassava; sago is from the pith of the sago palm; arrowroot is from a plant of the same name, a native of the West Indies. Rice is almost pure starch, while wheat and other cereals contain from sixty to seventy per cent.
Starch lacks flavor and for this reason all starchy foods are seasoned.
All starches must undergo much chemical change by action of the saliva, the intestinal juice and by the liver, before they can be used by the body. They are first converted into dextrine and then into maltose (animal sugar). The digestion is begun by the saliva in the mouth and continued in the stomach by the saliva swallowed with the food. If the saliva fails to digest all of the starch, either in the mouth or the stomach, it passes unchanged into the intestines, where it is converted by the amylase of the intestinal juice, first into dextrine and then into maltose, or sugar. It is absorbed into the blood as sugar. After the digested starch (maltose) passes into the blood it is spoken of as sugar. Before it is converted into energy it is again changed in the liver into animal starch (glycogen) and stored for a time in the liver. When the system is ready for it, it is again broken down into sugar, because in the form of glycogen it cannot be absorbed into the blood.
The chemical process used in the formation of glucose, from the starch in corn, is allied to the change in the liver, from starch into sugar.
The starches and sugars are really the “reserves” or “go-betweens” of the body, being stored until needed.
If starches are consumed in unduly large quantities, without sufficient exercise to burn them up, they overload the liver and clog the system.
Starchy foods should not be given to children before the starch converting ferments are formed, nor to one in disease where these ferments are interrupted.