We need enough food to repair the waste, to perform our work and to furnish heat. Every muscle contraction uses up a little energy. Every breath deprives us of heat and carries away carbon dioxide, the latter being formed by oxidation of tissues in the body. Every minute we lose heat by radiation from the skin. Every thought requires a small amount of food. If we worry, the leak of nervous energy is tremendous, but at the same time we put ourselves in position where we are unable to replenish our stock, for worry ruins digestion. All this expenditure of energy and loss of heat must be made up for by the food intake. Only a small amount of surplus food can be stored in the body. Some fat can be stored as fat. Some starch and sugar can be put aside as either glycogen—animal sugar—or be changed into fat. This storing of excess food is very limited, except in cases of obesity, which is a disease.
Overeating invariably causes disease. It may take two or three years, yes even twenty or thirty years, before the overeating results in serious illness, but the results are certain, and in the meanwhile the individual is never up to par. He can use neither body nor mind to the best advantage.
To emphasize and illustrate these remarks, I shall copy a few diet lists, which their authors consider reasonable and correct for the average person for one day, and I shall give my comments. The first is taken from Kirke's Physiology, which has been used extensively as a text-book in medical colleges:
340 grams lean uncooked meat,
600 " bread,
90 " butter,
28 " cheese,
225 " potatoes,
225 " carrots.
An ounce contains 28.3 grams; a pound, 453 grams. It is easy to figure these quantities of food in ounces or pounds, which give a better idea to the average person.
It is self-evident that this is too much food. Over twelve ounces of lean, uncooked meat, over twenty-one ounces of bread, almost one-half of a pound each of potatoes and carrots, about an ounce of cheese and over three ounces of butter make enough food for two days, even for a big eater. He who tries to live up to a diet of this kind is sure to suffer disease and early death.
The average loaf of bread weighs about fourteen ounces. Here we are told to devour one-half of a pound of carrots (for which other vegetables such as turnips, parsnips, beets or cabbage may be substituted), one-half of a pound of potatoes, three-fourths of a pound of lean raw meat, which loses some weight in cooking, a loaf and one-half of bread, besides butter and cheese. The vast majority of people can not eat more than one-third of this amount and retain efficiency and health, but many eat even more.
The next table is taken from Dr. I. Burney Yeo's book on diet, and is given as the food required daily by a "well nourished worker":
151.3 grams meat,
48.1 " white of egg,
450.0 " bread,
500.0 " milk,
1065.9 " beer,
60.2 " suet,
30.0 " butter,
70.0 " starch,
17.0 " sugar,
4.9 " salt.
This worker is too well fed. Often those who are so well fed are poorly nourished, for the excessive amount of food ruins the nutrition, after which the food is poorly digested and assimilated. This worker eats so much that he will be compelled to do manual labor all his days, for such feeding prevents effective thinking.