Compare this with the number of calories furnished by the ingredients in the hundred-calorie portions. WEIGHT OP CALORIES FROM 100-CALORiE PORTION Protein Fat Carbohydrate Boiled potato . . 3| OZ. 11 1 88 Wheat flour . . loz. 12 3 85 It is at once evident that they are not so unlike in their nutritive elements, but that about four times as much weight of potato must be had to provide the same amount of energy. If potatoes cost five cents for three pounds (If ^ per pound) and flour is five cents a pound, it is easy to cal- culate that four pounds of potatoes would cost six and two-thirds cents, while a pound of white flour would fur- nish the same amount of fuel value for five cents. Compare milk with flour. WATEB PROTEIN FAT CARBO- HYDRATE Flour . . . » . 12.8% 10.8% 1.1% 74.8% Milk 87.0% 3.3% 4.0% 5.0% The difference in the percentage of water present in the two makes it hard to decide which really furnishes the more protein, or fat, or carbohydrate. WEIGHT OF IOO-CALORIE PORTION CALORIES FROM Protein Fat Carbohydrate Flour .... Milk 1 OZ. 5+oz. 12 19 3 52 85 29 THE AMOUNT OF FOOD NECESSARY 157 It may be seen at once, by the second table, that over five times as much milk is necessary to equal the total calories in flour, but that the milk will furnish almost twice as many calories from protein. If milk costs four cents a pint (about a pound), it is evidently much more expen- sive both as a source of energy and as a source of protein. Such comparisons are of great interest, for food value and cost, curiously, have no connection with each other. Some of the government pamphlets show by graphs the amount of fuel value which can be purchased in different foods for a given amount of money, but the price of foods changes so rapidly that these quickly become antiquated. In addition to the recognized food principles, there seems to be another class of substances present in foods, which are known as vitamines. These are present in natural foodstuffs in only small amounts, but they seem necessary, some for nutrition and others for growth. Fruits, vegetables, and milk are our best sources for these substances, so far as is known at present. The whole subject of vitamines is under investigation, and it is to be hoped that before long we shall be able to speak more definitely concerning them. However, they furnish an excellent additional reason for the inclusion of fruits and vegetables in our diet. In all these discussions, it should be remembered, no account has been taken of mineral matter. Sherman says that of the mineral elements, only calcium, iron, and phos- phorus need to be considered, if the diet be sufficient and balanced. (See the Appendix.) Since many of our servings of food are about a hun- dred-calorie portion or bear a simple relation to it, it is convenient to use such a table in estimating the fuel value of a meal. A table of this kind will be found in the Appendix. 158 FOOD STUDY REFERENCES U. S. Dept. of Agriculture. Office of Exp. Sta. Bulletin No. 28. "The Chemical Composition of American Food Materials." QUESTIONS 1. Describe Swiss chard. Why is it not commonly found in the market? 2. List leaves which may be substituted for spinach as "greens." 3. Can the outer leaves of lettuce, not desirable for salad, be used in this way ?

AI-modernized reading of the original text

Compare this with the number of calories furnished by the ingredients in the hundred-calorie portions. WEIGHT OP 100-CALORiE PORTION Protein Fat Carbohydrate Boiled potato . . 3| OZ. Wheat flour . . . loz. It is at once evident that they are not so unlike in their nutritive elements, but that about four times as much weight of potato must be had to provide the same amount of energy. If potatoes cost five cents for three pounds (If ^ per pound) and flour is five cents a pound, it is easy to calculate that four pounds of potatoes would cost six and two-thirds cents, while a pound of white flour would furnish the same amount of fuel value for five cents. Compare milk with flour. WATEB FAT CARBO- HYDRATE Flour . . . » . 12.8% 10.8% 1.1% 74.8% Milk 87.0% 3.3% 4.0% 5.0% The difference in the percentage of water present in the two makes it hard to decide which really furnishes the more protein, or fat, or carbohydrate. WEIGHT OF IOO-CALORIE PORTION Protein Fat Carbohydrate Flour .... Milk 1 OZ. 5+oz. It may be seen at once, by the second table, that over five times as much milk is necessary to equal the total calories in flour, but that the milk will furnish almost twice as many calories from protein. If milk costs four cents a pint (about a pound), it is evidently much more expensive both as a source of energy and as a source of protein. Such comparisons are of great interest, for food value and cost, curiously, have no connection with each other. Some of the government pamphlets show by graphs the amount of fuel value which can be purchased in different foods for a given amount of money, but the price of foods changes so rapidly that these quickly become antiquated. In addition to the recognized food principles, there seems to be another class of substances present in foods, which are known as vitamines. These are present in natural foodstuffs in only small amounts, but they seem necessary, some for nutrition and others for growth. Fruits, vegetables, and milk are our best sources for these substances, so far as is known at present. The whole subject of vitamines is under investigation, and it is to be hoped that before long we shall be able to speak more definitely concerning them. However, they furnish an excellent additional reason for the inclusion of fruits and vegetables in our diet. In all these discussions, it should be remembered, no account has been taken of mineral matter. Sherman says that of the mineral elements, only calcium, iron, and phosphorus need to be considered, if the diet be sufficient and balanced. (See the Appendix.) Since many of our servings of food are about a hundred-calorie portion or bear a simple relation to it, it is convenient to use such a table in estimating the fuel value of a meal. A table of this kind will be found in the Appendix. U. S. Dept. of Agriculture. Office of Exp. Sta. Bulletin No. 28. "The Chemical Composition of American Food Materials." 1. Describe Swiss chard. Why is it not commonly found in the market? 2. List leaves which may be substituted for spinach as "greens." 3. Can the outer leaves of lettuce, not desirable for salad, be used in this way ?

Food study