Rye. Rye also contains a considerable amount of gluten, but is much poorer in starch than wheat is; and the bread made out of its flour—the so-called "black bread" of France and Germany—is dark, sticky, and inclined to sour readily. Most of the "rye" bread sold in the shops, or served on our tables, is made of wheat flour with a moderate mixture of rye to give the sour taste.
Rice. Rice consists chiefly of starch, and makes nutritious puddings or cakes, and may be used as a vegetable, in the place of potatoes, with meat and fish. It is, however, lacking in flavor, and when properly cooked, contains so much water that it has to be eaten in very large amounts to furnish much nutrition.
Potatoes. The only important starchy food outside of the grains is potatoes. These contain considerable amounts of starch, but mixed with a good deal of cellulose, or vegetable fibre, and water, so that, like rice, large amounts of them must be eaten in order to furnish a good fuel supply. They, however, make a very necessary article of diet in connection with meats, fish, and other vegetables.
As a rough illustration of the fuel value of the different starch foods, it may be said that in order to get the amount of nourishment contained in an ordinary pound loaf of wheat or white bread, it would be necessary to eat about seven pounds of cooked rice, as it comes on the table; about twelve pounds of boiled potatoes; or a bowl of oatmeal porridge about the size of a wash-basin.
SUGARS
Where Sugar is Obtained. The other great member of the starch, or carbohydrate, group of foods is sugar. This is a scarcer and more expensive food than starch because, instead of being found in solid masses in grains and roots like starch, it is scattered, very thinly, through the fruits, stems, and roots of a hundred different plants, seldom being present in greater amounts than two or three per cent. It is, however, so valuable a food, with so high a fuel value, and is so rapidly digested and absorbed, that man has always had a very keen desire for it, or, as we say, a "sweet tooth," and has literally searched the whole vegetable kingdom the world over to discover plants from which it could be secured in larger amounts. During the last two hundred years it has been obtained chiefly from two great sources: the juicy stem of a tall, coarse reed, or cane, the sugar-cane, growing in the tropics; and (within the last fifty years) the sweet juice of the large root of a turnip-like plant, the beet. Another source of sugar, in the earlier days of this country, was the juice or sap of the sugar maple, which is still greatly relished as a luxury, chiefly in the form of syrup.
Honey is nearly pure sugar together with certain ferments and flavoring extracts, derived in part from the flowers from which it is gathered, and in part from the stomach, or crop, of the bee.
The Food Value of Sugar. In the early days of its use, sugar, on account of its expensiveness, was looked upon solely as a luxury, and used sparingly—either as a flavoring for less attractive foods, or as a special treat; and like most new foods, it was declared to be unwholesome and dangerous. But sugar is now recognized as one of our most useful and valuable foods. In fuel value, it is the equal, indeed the superior, weight for weight, of starch; and as all starch has to be changed into it before it can be used by the body, it is evident that sugar is more easily digested and absorbed than starch, and furnishes practically a ready-made fuel for our muscles.
How We should Use Sugar. The drawbacks of sugar are that, on account of its exceedingly attractive taste, we may eat too much of it; and that, because it is so satisfying, if we do eat too much of it either between meals or at the beginning of meals, our appetites will be "killed" before we have really eaten a sufficient supply of nourishing food. But all we have to do to avoid these dangers is to use common sense and a little self-control, without which any one of our appetites may lead us into trouble.