132 A STUDY OF FOODS AND DIETARIES 



protoplasm, as well as an amount necessary to supply energy to 

 the body. It has been found, as a result of studies by Atwater 

 and others, that a man who does muscular work requires nearly 

 one quarter of a pound of protein, the same amount of fat, and 

 a little less than one pound of carbohydrate to pro\dde for the 

 growth, waste, and repan of the body and the energy used up in 

 one day. The proportion of protein in the diet is called the nutri- 

 iive ratio. 



The Daily Calorie Requirement. — Put m another way, At- 

 water says that for every 100 calories furnished by the food, 14 

 should be from protein, 32 from fat, and 54 from carbohydrate. 

 Professor Chittenden of Yale University, another food expert, 

 thinks we need proteins, fats, and carbohydrates in about the pro- 

 portion of 1 to 3 to 6, thus differing from Atwater in giving less 

 protein in proportion. For every 100 calories furnished by the 

 food, 10 should be from protein, 30 from fat, 60 from carbohydrate. 

 A German named Voit gives as ideal 25 calories from proteins, 20 

 from fat, and 55 from carbohydrate, out of every 100 calories ; this 

 is nearer our actual daily ration. In addition, an ounce of salt 

 and nearly one hundred ounces of water are used in a day. 



A Mixed Diet Best. — Knowing the proportion of the different 

 nutrients required by man, and the foods containing vitamins, 

 it will be an easy matter to determine from the foregoing 

 tables and charts the best foods for use in a mixed diet. Meats 

 contain so much nitrogen that they should be eaten with other 

 foods. In milk, the proportion of proteins, carbohydi'at^s, and 

 fats is nearly right to make protoplasm, a considerable amount 

 of mineral matter also being present. For these reasons, milk is 

 extensively used as a food for children, as it combines food material 

 for the forming of protoplasm with mineral matter for the building 

 of bone, and it also contains the vitamins. Some vegetables (for 

 example, peas and beans) contain a large amount of nitrogenous 

 material, but not all the amino-acids needed for growth seem to be 

 present. A purely vegetable diet contains much waste material, 

 such as the cellulose forming the waUs of plant cells, which is in- 

 digestible. 



Basal Metabolism. — The life activities of a plant or animal, 

 which include all the chemical processes that go on in the body, 



