| Age in Years | Calories per Pound of Normal Body Weight | Calories per Day |
| Under 1 year | 50-45 | 280-900 |
| 1-2 | 45-40 | 900-1200 |
| 2-5 inclusive | 40-35 | 1200-1500 |
| 6-9 ” | 35-30 | 1400-2000 |
| 10-13 ” | 30-25 | 1800-2200 |
| 14-17 ” | 25-20 | 2300-3000 |
| 18-25 ” | 16-18 | 2000-3400 |
Proportions of Food Elements. To furnish what is termed a “balanced ration”, the protein, carbohydrate, and fat should each constitute, in the total calories for the day, approximately the following proportions: protein 10 to 15 per cent., carbohydrate 50 to 60 per cent., fat 25 to 35 per cent. To some extent the fat and carbohydrate are interchangeable, but a great excess of fat or carbohydrate produces indigestion, and great insufficiency of fat starves the nerves. Each gram (about 1/28 ounce) of protein or carbohydrate furnishes four calories of heat; each gram of fat furnishes nine calories. Without sufficient protein, the child will not increase in growth. An excess of protein is no less injurious, as it cannot be stored in the body, but must be eliminated. Especially injurious is an excess of proteins containing purin-bodies, which produce urea and uric acid, thereby causing forms of kidney disease, gout, and rheumatisms. Excess of food, combined with sluggish elimination, produces putrefaction and fermentation in the intestine, resulting in auto-intoxication from the poisonous gases and chemicals, thereby inducing irritability, nervousness, languor, low resistance to germ diseases, colds.
In childhood and maternity a purin-free diet and one least likely to produce auto-intoxication is especially important.
A sufficient proportion of minerals is no less essential to life and health, although these are needed in minute quantities. Research in physiological chemistry has only recently discovered the vital significance of minerals. The quantities needed in childhood are not yet exactly known. Not only the bones and teeth but each cell and fluid requires mineral matter. The digestion and assimilation of food, the absorption of oxygen and the elimination of carbonic acid gas by the blood, the normal action of the heart, the generation of energy, the sensitiveness and reaction of the nerves, are all dependent upon the mineral supply in the system. There are no less than twelve, the principal ones being calcium, phosphorus, iron, soda, potash, sulphur. Calcium (lime) is especially needed for bones and teeth, phosphorus for growth and for nerve cells, iron for red blood corpuscles, soda for elimination of carbonic acid gas. The daily requirements for a man are:
Lime .7 gram; Phosphorus 2.75 grams; Iron .015 gram.
The allowance for a child should probably approximate this, and growing children probably need more of lime and phosphorus.
Minerals supplied to the body in vegetable and animal tissues or fluids have in some way been vitalized and made organic, so they are readily assimilated by the system. Mineral matter as dug from the earth and purchased at the drugstore is inorganic and is not assimilated either so thoroughly or readily.
Vitamines are equally essential in the food. These are subtle organic substances, as yet little understood, but necessary for perfect assimilation. Cooking, especially at a high temperature or for a long period, usually diminishes the vitamines in foods. This is one special objection to boiled, condensed, and powdered milk, patent baby foods, canned vegetables, canned, dried and salted meats. Children kept exclusively on such foods and boiled water do not thrive. Such a diet produces scurvy. Some fresh, uncooked food, such as raw milk, uncooked fruit or fruit juices, uncooked vegetables, is needed every day.
Laxative elements are also essential. These are (a) cellulose, found in the husk of whole wheat, and the fibers of vegetables and fruits; (b) water, found in milk, vegetables, and fresh or stewed fruits; (c) oil, found in cream, olive oil, and fatty nuts; (d) sugars, found in honey, molasses, dried fruits; (e) vegetable acids, found in fruits.
Hard foods, requiring work of the jaws, are needed every day, especially from nine months to seven years of age, while the first and second teeth are coming. Hard foods exercise and develop the jaws and teeth, and promote a good circulation through the jaws, mouth, and nose. They may be supplied by a chicken or chop bone wiped free of the cooked meat, or after nine months by hard crust, hard toast, zwieback, or educator crackers, given at one or two meals every day. Soft, mushy foods as a steady diet are injurious, not only because they fail to supply the needed exercise and circulation, but also because they cling to the teeth, and by fermenting produce their early decay.