In estimating food requirements of those who are under twenty-five years old, we must bear in mind that the same materials which serve for fuel serve in part for building material. Protein is used for muscle building as well as for supplying energy, and the larger one grows, the greater the reserves of carbohydrate and fat which he can carry. Furthermore, internal activity is greater in the young than the middle aged or very old, and external activity is apt also to be greater. Think, for instance, how much running children do compared with their parents. For all these reasons, we cannot use the table for adults in calculating the energy requirement of young people. In the following table an attempt has been made to take ac-count of their greater needs, but the estimates include only moderate exercise; with hard work more will be required. Notice that the highest allowance per pound of body weight is for the youngest children.

Age in Years

Calories per pound per day

Under 1 ..........................................................

45

1-2 ..........

45-40

2-5 ..........

40-36

6-9 ..........

36-30

10-13 ..........

30-27

14-17 ..........

. 27-20

17-25 ......................................................... .........

not less than 18

With these two tables for calculating energy requirement we can determine about how much will be needed by each member of the family. A group consisting of a professional man, his wife, and three children under 16 will require about 10,000 Calories per day; a workingman's family with the same number of children from 12,000 to 14,000, because of the harder work which both parents and possibly the children will do.