Under this class come cereals, legumes, nuts, milk, and milk products. In these foods the nitrogenous and carbonaceous elements are more evenly proportioned than in either the carbonaceous or nitrogenous groups. The different food elements in this group are so evenly divided that one could live for a considerable length of time on any one food. Some animals build flesh from nuts alone, while the herbivorous animals live on cereals and plants.
Cereals
Under cereals, used by man for food, come wheat, oats, rye, barley, rice, and corn. As will be noted by Table [V], cereals contain a large proportion of starch and are therefore used largely for heat and energy. Rice contains the largest proportion and next to rice, wheat flour.
TABLE V
Cereals
| Carbohydrates | ||||||
| FOOD MATERIALS | Water per cent. | Protein per cent. | Fat per cent. | Starch, etc. per cent. | Crude fiber per cent. | Ash per cent. |
| Wheat | 10.4 | 12.1 | 2.1 | 71.6 | 1.8 | 1.9 |
| Rice | 12.4 | 7.4 | 0.4 | 79.2 | 0.2 | 0.4 |
| Oats | 11.0 | 11.8 | 5.0 | 59.7 | 9.5 | 3.0 |
| Rye | 11.6 | 10.6 | 1.7 | 72.0 | 1.7 | 1.9 |
| Breads and Crackers: | ||||||
| Wheat bread | 32.5 | 8.8 | 1.9 | 55.8 | .... | 1.0 |
| Graham bread | 34.2 | 9.5 | 1.4 | 53.3 | .... | 1.6 |
| Rye bread | 30.0 | 3.4 | 0.5 | 59.7 | .... | 1.4 |
| Soda crackers | 8.0 | 10.3 | 9.4 | 70.5 | .... | 1.8 |
| Graham crackers | 5.0 | 9.8 | 13.5 | 69.7 | .... | 2.0 |
| Oatmeal crackers | 4.9 | 10.4 | 13.7 | 69.6 | .... | 1.4 |
| Oyster crackers | 3.8 | 11.3 | 4.8 | 77.5 | .... | 2.6 |
| Macaroni | 13.1 | 9.0 | 0.3 | 76.8 | .... | 0.8 |
| Flours and Meals: | ||||||
| Flour, wheat | 12.5 | 11.0 | 1.0 | 74.9 | .... | 0.5 |
| Corn Meal | 15.0 | 9.2 | 3.8 | 70.6 | .... | 1.4 |
| Oatmeal | 7.6 | 15.1 | 7.1 | 68.2 | .... | 2.0 |
The values as given in the table refer to the whole of the grain. When the outer coverings are removed, as in the white flour and the outer covering of rice, the proportion of carbohydrates is increased and the protein and ash are almost entirely eliminated.
There is no part of the world, except the Arctic regions, where cereals are not extensively cultivated. From the oats and rye of the north, to the rice of the hot countries, grains of some kind are staple foods.
An idea of the importance of cereal foods in the diet may be gathered from the following data, based on the results obtained in dietary studies with a large number of American families: Vegetable foods, including flour, bread, and other cereal products, furnished 55 per cent. of the total food, 39 per cent. of the protein, 8 per cent. of the fat, and 95 per cent. of the carbohydrates of the diet. The amounts which cereal foods alone supplied were 22 per cent. of the total food, 31 per cent. of the protein, 7 per cent. of the fat and 55 per cent. of the total carbohydrates—that is, about three-quarters of the vegetable protein, one-half of the carbohydrates, and seven-eighths of the vegetable fat were supplied by the cereals. Oat, rice, and wheat breakfast foods together furnished about 2 per cent. of the total food in protein, 1 per cent. of the total fat, and 4 per cent. of the carbohydrates of the ordinary mixed diet, as shown by the statistics cited. These percentage values are not high in themselves, but it must be remembered that they represent large quantities when we consider the food consumed by a family in a year.[4]
If one’s work calls for extreme muscular exertion, the cereals may be eaten freely, but if one’s habits are sedentary, and the cereals are used in excess, there is danger of clogging the system with too much starch. Indeed, for one whose occupation is indoors and requires little muscular activity, a very little cereal food, such as bread, cake, etc., will suffice; the carbohydrates will be supplied, in sufficient quantity, in vegetables.