USE AND PREPARATION OF FOOD. people use np less, due to a general slowing down of the body processes. C. Little, if any, additional fuel is needed for mental activity. 3. Method of estimating the amount of fuel needed: A. The fuel value of foods is measured by the calories. (See Unit XII, Lesson 3.) The number of calories needed per day for an}' individual may be calculated from the following table: Tabic for calculating energy requirements. Kind of activitv. Sleeping Sitting quietly Standing Light exercise. Calories per pound of body weight per hour. Kind of actnity. Moderate exercise Active exercise. . . Severe exercise... Calories per pound of body weight per hour. IJ to2 3 or more. 4. Foods which furnish fuel : A, The principal sources of energy are the foods which supply carbohydrate (or starches and sugar) and those supplying fat. (1) Starch is used in the average diet as the principal source of energy. Comparatively large amounts can easily be used by the body because of the bland flavor and because of the ease and completeness of digestion. The largest amount of starch is sup- plied by cereals, including flours, meals, breakfast foods, and breads of various kinds. Dry cereals average about 1,G00 calories to the pound. A considerable amount of starch is also furnished by the legumes and by potatoes and other starchy vegetables. (2) Sugars. — These include various household forms of su- gars and sirups as well as the sugar found in milk, fresh and dried fruit, or other foods. Sugar is used in the diet both to supply energy and to furnish flavor. It digests more rapidly than other foods; therefore, it is a quick source of heat in the bodj^, but on acount of the high flavor and a tendency to cause irritation, it should not be eaten in large quantities. Sugar can more easilj^ be omitted from the diet than any other class of foods since the energy furnished by it can be supplied just as well by the starchy foods. (3) Fats. — These are the most concentrated forms of energy, a given amount furnishing two and one-quarter times as much fuel as an equal weight of sugar or starch. They are used in the diet to furnish fuel and also to furnish flavor. Fats digest more slowly than either starches or sugars, hence are valuable to give food a "staying" quality and to furnish a sense of satisfaction after eating. When fats are scarce, the}' may be reduced to the USE AND PREPARATION OF FOOD. 205 minimum (14 ounces per day), but they should not be entirely omitted. Some kinds of fats contain substances extremely valu- able to the body. (See Lesson 5.) Protein foods may be used to furnish some fuel, but their extensive use for this purpose is uneconomical. 5. Eifect upon the body of too much fuel food; too little fuel food: A. When fuel foods are taken into the body, they are digested, absorbed, and burned, furnishing heat and leaving a harmless resi- due. When more fuel is taken in than the activity of the body de- mands, it is stored chiefly as body fat and kept in reserve. If at any time too little fuel food is eaten, the body draws upon this reserve of fat and converts it into energ3\ For this reason people suffering from overweight or underweight may frequently remedy the condi- tion by decreasing or increasing the amount of starch, sugar, and fat in the food.

AI-modernized reading of the original text

people use no less, due to a general slowing down of the body processes. C. Little, if any, additional fuel is needed for mental activity. 3. Method of estimating the amount of fuel needed: A. The fuel value of foods is measured by the calories. (See Unit XII, Lesson 3.) The number of calories needed per day for an}' individual may be calculated from the following table: Tabic for calculating energy requirements. Kind of activitv. Sleeping Sitting quietly Standing Light exercise. Calories per pound of body weight per hour. Kind of actnity. Moderate exercise Active exercise. . . Severe exercise... Calories per pound of body weight per hour. IJ to2 3 or more. 4. Foods which furnish fuel : A, The principal sources of energy are the foods which supply carbohydrate (or starches and sugar) and those supplying fat. (1) Starch is used in the average diet as the principal source of energy. Comparatively large amounts can easily be used by the body because of the bland flavor and because of the ease and completeness of digestion. The largest amount of starch is supplied by cereals, including flours, meals, breakfast foods, and breads of various kinds. Dry cereals average about 1,G00 calories to the pound. A considerable amount of starch is also furnished by the legumes and by potatoes and other starchy vegetables. (2) Sugars. — These include various household forms of sugars and sirups as well as the sugar found in milk, fresh and dried fruit, or other foods. Sugar is used in the diet both to supply energy and to furnish flavor. It digests more rapidly than other foods; therefore, it is a quick source of heat in the body, but on account of the high flavor and a tendency to cause irritation, it should not be eaten in large quantities. Sugar can more easily be omitted from the diet than any other class of foods since the energy furnished by it can be supplied just as well by the starchy foods. (3) Fats. — These are the most concentrated forms of energy, a given amount furnishing two and one-quarter times as much fuel as an equal weight of sugar or starch. They are used in the diet to furnish fuel and also to furnish flavor. Fats digest more slowly than either starches or sugars, hence are valuable to give food a "staying" quality and to furnish a sense of satisfaction after eating. When fats are scarce, they may be reduced to the minimum (14 ounces per day), but they should not be entirely omitted. Some kinds of fats contain substances extremely valuable to the body. (See Lesson 5.) Protein foods may be used to furnish some fuel, but their extensive use for this purpose is uneconomical. 5. Eifect upon the body of too much fuel food; too little fuel food: A. When fuel foods are taken into the body, they are digested, absorbed, and burned, furnishing heat and leaving a harmless residue. When more fuel is taken in than the activity of the body demands, it is stored chiefly as body fat and kept in reserve. If at any time too little fuel food is eaten, the body draws upon this reserve of fat and converts it into energy. For this reason people sufferingfrom overweight or underweight may frequently remedy the condition by decreasing or increasing the amount of starch, sugar, and fat in the food.

Use and preparation of food