Yeast breads made with a variety of flours serve as the constant bread of humanity. Bread dough, besides being itself made in many ways, is used as a basis for other foods, as doughnuts. These all vary somewhat. Some add fat that bread lacks. Others include more sugar, also fruit and nuts.

Such changes in bread usually increase its heat-energy, but may decrease somewhat its digestibility. They produce variety in the diet and are used for this purpose where the supply of fresh foods is limited and living is largely out-of-doors. These conditions in the early days of New England effected many such modifications in flour-foods not now essentially needed.

Starch, the principal food-ingredient in bread, because gradually digested, makes bread a food that so lasts as to prevent over-frequent need for food. Foods that increase fat and sugar give in these more rapidly available energy than starch can. Starch must be made into a kind of sugar before it can be digested. In bread-baking the starch in the crust is changed to dextrin (a soluble sugar). Hence the advice to give children crusty bread. Adults by thorough mastication of food bring it more fully within the activity of the digestive juices than little children can. Adults can therefore use what children should not even try to digest.

Baking-powder breads vary as do yeast breads. They may be plain or variously enriched. They are usually served hot, so require every care to make them digestible. They include muffins, breakfast and tea breads of all kinds, such as corn-bread, cereal and sweetened muffins, and biscuit.

Many such foods introduce a number of animal food elements in milk, butter, eggs, so are not as distinctly vegetable foods as bread itself may be. This does not decrease their value as foods, but modifies their use.