Dietary studies have been made in considerable numbers in different countries. The results of such studies and experiments to determine the amount of food required by men engaged in different occupations have resulted in the adoption of dietary standards. Some of these follow:

Standards For Daily Dietaries

Character of Work to be Performed.

Nutrients.

Fuel. Value.

Protein.

Fat.

Carbohydrates.

European:

Pound.

Pound.

Pounds.

Calories.

Man at moderate work...................

0.26

0.12

1.10

3,055

Man at hard work...................

.32

.22

.99

3,370

American:

Man without muscular work............

.20

3,000

Man with light muscular work............

.22

3,000

Man with moderate muscular work........

.28

3,500

Man with hard muscular work............

.39

4,500

The table of composition of food materials shows the amount of water, protein, fat, carbohydrates and ash content and the total fuel value per pound for each kind of food named. The protein, fat and carbohydrates all furnish energy. In addition to furnishing energy, protein forms tissue. Since protein and energy are the essential features of food, dietary standards may be expressed in their simplest form in terms of protein and energy alone.

Observation has shown that as a rule a woman requires less food than a man, and the amount required by children is still less, varying with the age. It is customary to assign certain factors which shall represent the amount of nutrients required by children of different ages and by women as compared with adult man. The various factors which have been adopted are as follows: