for the house from the wood and coal we put into the furnace.
The fats yield two and one-quarter times as much energy for a given weight as do the starches and sugars. But they are more costly and more difficult to digest, more concentrated, and so we can use less of them, about one-quarter to one-third of our food being fats. Three-fifths of the ration should be from sugars and starches, the latter being our leading body fuel.
The grains lead as a starch supply, as they are three-fourths carbohydrates; the beans and peas come next with three-fifths, and the potato, as eaten, has one-fifth.
Another point to remember is that unless we have enough of the fuel foods (starches, sugars, and fats), the body will eventually burn its protein to get enough energy and warmth. So undernourishment, stunted growth, and general disability may all result indirectly from having too little of the fuel foods, as well as from having too few of the building proteins, vitamins, or minerals.
And whether we use the fuel foods for energy for doing work, or store them in the body in the form of fat, depends on our activities in relation to the amount of food eaten. The same amounts of sugar, butter, cereals, and breads may spell energy and muscle for the athlete, and dullness and fat for the Lady of the Hammock or for the Man-Behind-the-Desk who exercises his brains only![ 19 ]
