Where does the body get its food? And how much does it require of each kind?
Children are different from adults in this respect. They require more nourishment as measured in calories and they also require more protein in order to allow for growth, and more minerals per pound of body weight for the same reason.
A child’s diet should have 50 per cent of the total calories in the form of carbohydrate. Thirty-five per cent of its food should be in the form of fats. Fifteen per cent of its food should be in the form of protein. As regards mineral intake, it requires fairly large quantities of calcium, phosphorus and iron. It requires all the vitamins. As to fluid, it requires at least four glasses of water a day, plus one quart of milk.
What function do these elementary food substances perform in the body?
Carbohydrates and fats supply energy and are rapidly used up, as gasoline supplies energy to an automobile and is rapidly used up.
Roughage is largely found in the carbohydrate content of breads and fruits, and is used to stimulate body excretion.
Minerals are held in solution in the fluids of the body, and maintain neutrality of blood, regularity of heart beat, and nervous equilibrium, the response of muscles, and are used to make sound teeth and strong bones.
Vitamins are necessary for health and growth and resistance to infection.
Water acts as a solvent for nutritive material, as a carrier for food and the removal of waste. It regulates body temperature.
The sources of these substances in the food are roughly as follows:
Carbohydrates come from sugars and starches, vegetables and fruits, bread, milk and cereals.
The fats come from butter, cream, egg yolk, and the fat part of meat.
The protein comes from milk, eggs, meat, and in some vegetable substances such as bread, cereal, beans and peas.
Minerals come from practically all the foods.
Calcium comes especially from milk and fruits.
Iron comes especially from eggs and spinach and green leafy vegetables.
Phosphorus comes from milk, eggs, bread, vegetables and fruits.
The vitamins are found in all foods, especially fresh foods such as milk, butter, yeast and fruits. The only vitamin which is not necessarily present in the average diet is Vitamin D, which may be substituted by the use of cod liver oil or viosterol.