FUEL VALUE OF FOODS

Expressed in terms of English weight, the fuel value of the three different food elements would be:

1 ounce of carbohydrates127.5 calories
1 ounce of proteins127.5 "
1 ounce of fat289.2 "

It will be observed that fat contains more than twice as much heat as the carbohydrates. This is due to the fact that fat contains more carbon than either starch or sugar. Next to fats, starches and sugars are the most important fuel elements. Protein is a very extravagant form of food for fuel purposes. Proteins are the most expensive elements of human food; they are incompletely burned in the body, and inasmuch as they leave behind distressing and disease-producing ashes, it is clearly evident that only sufficient amount of proteins should be eaten each day to supply the demand of the body for repairs. We should depend more largely upon the carbohydrates and fats for heat and energy.

A large part of our food is required to furnish heat to take the place of that lost by radiation from the skin, and this is why children require more food than adults—they have a larger skin surface in proportion to their weight, and therefore lose more heat by radiation, and it is for this reason that the food for the growing child must be wisely and carefully selected.