.05 x 4 = .20 calorie from carbohydrate
or .692 calorie in all

But it is not necessary to estimate the fuel value of so small a
quantity as one gram, and, since the value of protein, carbohydrates
and fats is always the same it is more satisfactory to estimate the
amount of the organic constituents contained in the entire given
quantity of food, rather than stopping to figure out the fuel value of
the small quantity.

This is done by multiplying the entire number of grams of food given
by the amount of protein, fat and carbohydrate contained in one gram,
then multiplying these results by the physiological fuel factor of
each. Thus 100 grams of milk would yield

100 x .033 = 3.3 x 4 = 13.2 calories from protein
100 x .04 = 4.0 x 9 = 36.0 calories from fat
100 x .05 = 5.0 x 4 = 20.0 calories from carbohydrates
or a total of 69.2 calories from 100 grams of milk.

~The Standard or 100 Calorie Portion.~--Just as it has been more
convenient to estimate a larger rather than a smaller quantity of food
material, so it is frequently more desirable to estimate a hundred
calories, rather than one calorie. This is especially useful when
dietaries of high caloric (fuel) value are to be estimated, or
dietaries in which foods of like composition and fuel value are to be
interchangeable. In such cases it is a simple matter to select the
desired number of 100 calorie portions of those foods which are to
make up the dietary.[19]

~Method of Estimating the 100 Calorie Portion.~--The number of
calories yielded by 100 grams of food material is taken as a basis
upon which to estimate the 100 calorie portion, and X represents the
number of grams required to yield this portion. The problem is one of
"simple proportion," for example, take the 100 grams of milk just
estimated, we found that 100 grams (or c.c.) furnished 69.2 calories
of heat, then, 100:69.2 :: X:100--145; or 145 grams of milk are
required to furnish 100 calories of heat. Suppose it is desirable to
substitute eggs for a part of the milk in the diet, eggs have a higher
fuel value per unit of weight than milk, their average composition
being 13.4% protein, and 10.5% fat (no appreciable amount of
carbohydrates), 100 grams of eggs would yield

100 x .134 = 13.4 x 4 = 53.6 calories from protein
100 x .105 = 10.5 x 9 = 94.5 calories from fat,
or a total of 148 calories.

The Standard or 100 calorie portion of eggs would be,

100:148 :