256. Dietary Studies in Public Institutions.—Dietary studies in public institutions, as prisons, and asylums for the insane, show that it is possible to secure greater variety of food containing a larger amount of nutrients, and even at a reduction in cost.[[84]] In such institutions it is important that the food should be not only ample in amount, but wholesome and nutritious, as many of the inmates respond both physically and mentally to an improved diet. For humanitarian as well as economic reasons institutional dietetics should more generally be placed under the supervision of skilled dietists.
CHAPTER XVIII
RATIONAL FEEDING OF MAN
257. Object.—Rational feeding of man has for its object the regulation of the food supply in accord with the demands of the body. It is based upon the same principles as the rational feeding of animals; in each, the best results in the way of health, amount of labor performed, and economy are secured when the body receives nutrients sufficient for the production of heat and energy and for the repair of worn-out tissues. Rational feeding is simply regulation of the food, both as to kind and amount, to meet the needs of the body.[[72]]
258. Standard Rations.—In human feeding, as in animal feeding, it is not possible to lay down hard and fast rules as to the quantity of nutrients required for a standard ration.[[85]] As stated in the chapter on Dietary Studies, such standards have been proposed, but they are to be considered as tentative rather than absolute, for the amount of food required by different persons must necessarily vary with the individuality. While it is impossible to establish absolute standards, any large variation from the provisional standards usually results in lessened ability to accomplish work, ill health, or increased expense.
259. Amounts of Food Consumed.—The approximate amounts of some food articles consumed per day are as follows:
| Range | Approximate Amount in Lbs. | |
|---|---|---|
| Bread | 6 to 14 oz. | 0.50 |
| Butter | 2 to 5 oz. | 0.12 |
| Potatoes | 8 to 16 oz. | 0.75 |
| Cheese | 1 to 4 oz. | 0.12 |
| Beans | 1 to 4 oz. | 0.12 |
| Milk | 8 to 32 oz. | — |
| Sugar | 2 to 5 oz. | 0.20 |
| Meats | 4 to 12 oz. | 0.25 |
| Oatmeal | 1 to 4 oz. | 0.12 |
In the calculation of rations it is desirable that the amount of any food article should not exceed that designated, unless for some special reason it has been found the food can consistently be increased. The amount of nutrients given in dietary standards is for one day, and the nutrients may be divided among the three meals as desired. It is to be noted that, ordinarily, the foods which supply carbohydrates are flour, corn meal, cereal products, potatoes, beans, sugar, and milk; those which supply fat are milk, butter, lard, and meats; and those which supply protein in liberal amounts are beans, cheese, meats, oatmeal, cereals, bread, and milk.
260. Average Composition of Foods.—The amounts of nutrients in foods are determined from the average composition of the foods. These figures for average composition are based upon analyses of a large number of samples of food materials.[[7]] In individual cases it will be found that foods may vary from the standards given; as for example, milk may contain from 2.5 to 5 per cent of fat, while the protein and fat of meats vary appreciably from the figures given for average composition. With the cereals and vegetable foods, variations from the standards are small. In the table, the composition of the food as purchased represents all of the nutrients in the food, including those in the refuse, trimmings, or waste, while the figures for the edible portion represent the nutrients in the food after deducting what is lost as refuse. In making calculations, the student should use the figures given for the foods as purchased, unless the weights are of the edible portion only. The figures in the table are on the basis of percentage amounts, or nutrients in 100 pounds of food. By moving the decimal point two places to the left, the figures will represent the nutrients in one pound, and if this is multiplied by the number of pounds or fraction of a pound used, the quantity of nutrients is secured. For example, suppose bread contains 9.5 per cent of protein and 56 per cent of carbohydrates, 1 pound would contain 0.095 pound of protein, 0.56 pound of carbohydrates; and 0.5 of a pound would contain approximately 0.05 pound of protein and 0.28 pound of carbohydrates. In calculating rations, it is not necessary to carry the figures to the third decimal place.