Calories

With these thoughts in mind, let's review other changing attitudes that underlie today's thinking about nutrition. A too naive theory used to prevail for explaining regeneration through food.

The human system was thought of as an engine, and you kept it stoked with foods to produce energy. Food can be and still is measured in units of heat, or calories, a Calorie being the amount of heat needed to raise one kilogram of water one degree Centigrade.

Thus translated into food values, each gram of protein-egg, milk, meat, fish-is worth four calories; each gram of carbohydrate-starches and sugars-four calories; and each gram of fat-butters, vegetable oils, drippings, etc.-about nine.

The mere stoking of the body's engine with energy-producing foods may keep life going in emergencies. But food, to maintain health, must also have, besides its energy values, the proper proportions of biologic values.

Proteins, vitamins, enzymes, hormones, minerals and their regulatory functions are still too complicated to be fully understood. But fortunately for us the body is able to respond to them intuitively and instantly.

What we really possess, then, is not just a simple stoking mechanism, but a computing setup far more elaborate and knowledgeable than anything that man has been able to devise.

The body sorts and routes nutrients on their way as soon as they are ingested. Our job is to help it along as much as possible, neither stinting it nor overloading it.

Depending on age, weight and activity the following is a rough guide to the favorable division of daily caloric intake: about 15% for proteins, under 25% for fats and about 60% for carbohydrates.