It has been estimated that persons 60 years of age require 10 per cent. less food than they formerly did; those 70 years old, 20 per cent. less; and those 80 years old, 30 per cent. less. Usually the appetite regulates this decrease in food, for the less active a person is, the less likely is the appetite to be stimulated. However, the fact that there is also a great difference in persons must not be lost sight of. Some men and women at 70 years of age are as young and just as active as others at 50 years. For such persons, the decrease in quantity of food should not begin so soon, nor should it be so great as that given for the more usual cases.
46. As there is a decrease in quantity with advancing years, so should there be a difference in the quality of the food taken. That which is easily digested and assimilated is preferable to food that is rich or highly concentrated. Usually, it is necessary to increase the laxative food in the diet at this time of life, but this matter is one of the abnormalities of diet and therefore belongs properly to medical dietetics rather than to a lesson on normal diet.
DIET FOR INFANTS AND CHILDREN
47. From birth until a child has attained full growth, the food requirement is high in proportion to the size of the child. This is due to the fact that energy must be supplied for a great deal of activity, and at the same time new tissue must be manufactured from the food taken. It should be remembered, too, that all body processes during growth are extremely rapid. At birth, the average child weighs about 7 pounds, and for several days after birth there is a normal loss of weight. In a few days, however, if the diet is correct, the child begins to increase in weight and should gain about 1/2 pound a week until it is 3 months old. From this time on, its weekly gain should be slightly less, but it should be constant. If the weight remains the same or there is a decrease for a number of consecutive days or weeks, it is certain that the diet is incorrect, that the quantity of food is insufficient, or that the child is ill. The reason for the loss should be determined at once and the trouble then corrected.
Normal diet for the infant is the mother's milk, but if this cannot be supplied, the next best diet is modified cow's milk, which for the young child must be greatly diluted. If it is found necessary to give proprietary, or manufactured, foods, raw food of some kind should be used in addition, the best way to supply this being with a little orange juice or other fruit juice. At the age of 3 months, this may be given in small quantity if it is diluted, and then the amount may be gradually increased as the child grows older.
48. EFFECT OF WEIGHT ON CHILDREN'S DIET.--The food requirement in the case of children is determined by weight. To decide on the proper amount, it is necessary to know the normal weight at certain ages. At birth, as has been stated, the normal weight is 7 pounds; at 6 months, 15 pounds; at 1 year, 21 pounds; at 2 years, 30 pounds. The food requirement for 24 hours per pound of weight is as follows:
| CALORIES PER LB. IN 24 HOURS | |
| Children up to 1 year | 45 |
| Children from 1 to 2 years | 40 |
| Children from 2 to 5 years | 36 |
From a study of these figures, it will be noted that there is a gradual decrease in the required number of calories per pound as the child grows older. The decrease continues until maturity is reached, and then the scale for adults applies.
49. EFFECT OF AGE ON CHILDREN'S DIET.--A child should not be kept exclusively on milk for more than 6 or 8 months, and then only in case it is fed on the mother's milk. Fruit juice, which has already been mentioned as an additional food, is recommended if the diet requires raw food or if it is necessary to make the child's food more laxative. When the child reaches the age of 6 months, it should be taught to take foods from a spoon or a cup; then when it must be weaned, the task of weaning will be much easier. At the age of 8 or 9 months, depending on the condition of the child, small amounts of well-cooked, strained cereals may be added to the diet, and these may gradually be decreased as the food is increased in variety. Up to 1-1/2 years of age, a child should have 8 ounces of milk three times a day, which amounts to 1-1/2 pints. At this age, half of a soft-cooked egg or a spoonful or two of tender meat chopped very fine, may be given, and for each such addition 4 ounces of milk should be taken out of the day's feeding. But from 1-1/2 years up to 5 years, at least 1 pint of milk a day should be included in the diet.