1 ounce of sugar contains no protein, no fat, and 1 ounce carbohydrates. 1 ounce sugar yields (113 x 1 =) 113 Calories.
HOW THE WEIGHT OF FOOD MATERIALS PRODUCING 100 CALORIES IS MEASURED.—For practical work in computing the fuel value of foods, it has been found more convenient to reduce all data to terms which express equal fuel value instead of equal weight as in the foregoing paragraph. One hundred Calories is the unit chosen. The weight of a food which, when "burned" in the body, will produce one hundred Calories is the desired data. This weight is termed a standard portion or a 100-Calorie portion (see Figures 83 and 84).
From the previous work, it is a simple matter to compute in ounces the quantity of food materials which will yield 100 Calories.
If 1 ounce of flour yields 100.98 Calories and x represents the number of ounces of flour which will yield 100 Calories, then x/1=100/100.98 or x=0.99, the number of ounces of flour which yield 100 Calories, i.e. a 100-Calorie portion of flour.
If 1 ounce of butter yields 217.88 Calories and x represents the number of ounces of butter which will yield 100 Calories, then x/1=100/217.88 or x=0.45, the number of ounces of butter which yield 100 Calories, i.e. a 100-Calorie portion of butter.
[Illustration: FIGURE 84—100-CALORIE PORTIONS OF FOODS. a, banana, b, butter, c, eggs d, meat; e, bread.]
If 1 ounce of sugar yields 113 Calories and x represents the number of ounces of sugar which will yield 100 Calories, then x/1=100/113 or x=0.88, the number of ounces of sugar which will yield 100 Calories, i.e. a 100-Calorie portion of sugar.
HOW THE FUEL VALUE OF A COMBINATION OF FOOD MATERIAL IS MEASURED.—It is possible to compute the fuel value of a food that is made up of several food materials. To do this one must know or find:
(a) Recipe for food. (b) Weight and measure of combustible food materials. (c) Number of Calories yielded by one ounce of each of the combustible foodstuffs.
The recipe for one loaf of bread is: