DAILY ENERGY REQUIREMENT.—One hears much concerning working efficiency, i.e. the ability to do the maximum amount of work of the highest type with a minimum waste of effort. There is no doubt that the kind and quantity of food that an individual consumes has much to do with his working efficiency, and that it is consequently a matter worthy of serious consideration. Enough gasoline is used in an automobile so that there is produced sufficient power to move the car at the desired speed. So sufficient food should be used by the individual that enough energy be supplied to his body for its greatest usefulness.

Since foods furnish the body with energy, the energy which the body spends in doing its work is a measure of the fuel food needed. If the body requires a certain amount of energy for its needs, this energy, measured in Calories, can be supplied by a definite quantity of combustible food. Hence, daily energy requirements can be measured in Calories.

Scientists have done much experimenting and investigating concerning the quantity of food that individuals require. They have concluded that many factors may be taken into consideration in determining daily food requirements or dietary standards. Some of these factors are: (1) weight; (2) occupation; (3) age.

(1) Relation of Weight, Size, and Shape to Daily Energy Requirement.—In general the quantity of food required increases with the size of an individual but not at the same rate as the body weight increases. Two persons may be equal in weight, yet very different in height and shape. A tall, slender person requires more food than a short, fleshy person of the same weight. For this reason, size and shape rather than weight are found more accurate in computing the daily food requirement. However, for practical purposes, energy requirement is generally based upon body weight.

(2) Relation of Occupation to Daily Energy Requirement.—From the previous consideration of energy, it is obvious that muscular exercise, even though very slight, requires some expenditure of energy. It has been found that, even during sleep and rest, energy is required to carry on the functions of the body (such as the beating of the heart, etc.). Since the energy for both the voluntary and involuntary activities of the body is furnished by the fuel foods, it is clear that one's occupation is an important factor in determining the kind and quantity of food an individual should use.

The man who is doing hard physical work needs more food than the man who sits quietly at his employment.

The following table, showing the energy required for different conditions of activity, has been formulated by scientists: [Footnote 96: Atwater and Benedict, United States Department of Agriculture, Yearbook 1904, p. 215.]

Man sleeping requires 65 Calories per hour
Man sitting at rest requires 100 Calories per hour
Man at light muscular exercise requires 170 Calories per hour
Man at active muscular exercise requires 290 Calories per hour
Man at severe muscular exercise requires 450 Calories per hour
Man at very severe muscular exercise requires 600 Calories per hour

From these data, it is possible to compute the dietaries of people of different occupations. For example, the energy requirement for a bookkeeper (male) leading an inactive muscular life is:

8 hours sleep (65 Calories per hour) 520 Calories 9 hours work at desk (100 Calories per hour) 900 Calories 4 hours sitting at rest and reading (100 Calories per hour) 400 Calories 3 hours walking (170 Calories per hour) 510 Calories ——————- 2330 Calories

The energy requirement for a man of severe muscular activity, such as excavating, is:

8 hours sleep (65 Calories per hour) 520 Calories 8 hours excavating (450 Calories per hour) 3600 Calories 1 hour walking (170 Calories per hour) 170 Calories 7 hours sitting at rest (100 Calories per hour) 700 Calories ——————- 4990 Calories

Another authority [Footnote 97: "Textbook of Physiology," p. 141,
Tigerstedt.] gives these data pertaining to men engaged in muscular work:

Shoemaker requires 2001-2400 Calories per day
Weaver requires 2401-2700 Calories per day
Carpenter or mason requires 2701-3200 Calories per day
Farm laborer requires 3201-4100 Calories per day
Excavator requires 4101-5000 Calories per day
Lumberman requires 5000 or more Calories per day

The following data regarding the energy requirements of the average woman in some of her common occupations have been formulated [Footnote 98: See "Feeding the Family," p. 76, by Mary Swartz Rose, Ph.D.]:

At rest 1600-1800 Calories per day
Sedentary occupations 2000-2200 Calories per day
Milliners Teachers
Bookkeepers Seamstresses
Stenographers Machine operatives
Occupations involving standing, walking,
or manual labor 2200-2500 Calories per day
Cooks in family groups Chamber maids
General housekeepers Waitresses
Occupations developing muscular
strength 2500-3000 Calories per day
Laundresses Cooks for large groups

(3) Relation of Age to Daily Energy Requirement.—Young children, i.e. those under eight or nine years of age, do not require as much food as adults. The food requirement of a child and of an adult is not proportional to weight, however. In proportion to his weight a child requires more food than an adult. The growing child needs food, not only to give energy to the body and rebuild tissue, but to build new tissue. An aged person needs less food to build new tissue. Furthermore, since an old person's strength is somewhat lessened, he needs less food to carry on the activities of the body. Hence, the aged person requires less food than the adult of middle life. The following table [Footnote 99: From "Chemistry of Food and Nutrition," Second Edition, by Henry C. Sherman, Ph.D., p. 197.] gives the differences in energy requirement of children from one to seventeen years inclusive. It is thought that after the age of seventeen, food requirement will depend quite as much upon occupation as upon age. Hence, the foregoing tables can be used to estimate energy requirement for all ages above seventeen:

Children of 1-2 years inclusive 1000-1200 Calories per day
Children of 2-5 years inclusive 1200-1500 Calories per day
Children of 6-9 years inclusive 1400-2000 Calories per day
Girls of 10-13 years inclusive 1800-2400 Calories per day
Boys of 10-13 years inclusive 2300-3000 Calories per day
Girls of 14-17 years inclusive 2200-2600 Calories per day
Boys of 14-17 years inclusive 2800-4000 Calories per day

The fact that the energy requirement of the boy from 10 to 17 years is greater than that of the girl of equal age is due probably to the greater restlessness or muscular activity of the boy.

DAILY PROTEIN REQUIREMENT.—If a person's energy requirement were 2500 Calories, sufficient energy might be supplied by using butter or beef steak for a day's ration. Yet this would be extremely unpalatable and would not meet the needs of the body. The body should be nourished by all the combustible foodstuffs,—carbohydrates, fat, and protein. Now the question arises: How many of the required Calories shall be supplied by each of these foodstuffs?

Too much or too little protein is often harmful and produces serious results. As mentioned previously, too much protein may cause intestinal disturbances, and an overtaxing of the excretory organs. On the other hand, the use of too little protein may produce imperfect nourishment. Concerning the quantity of protein used in diet, there has been much difference of opinion. Atwater, an American authority, thought that there should be a generous supply, i.e. a surplus of protein, to supply the demands of body-building. Chittenden, another American authority, believes in just enough protein to meet the demands of the body. However, the use of sufficient protein food to produce from ten to fifteen per cent of the total Calories has been found both practical and satisfactory.

Daily Carbohydrate and Fat Requirement.—Although protein may furnish the body with energy, it should not serve as the principal source of fuel. Its more essential function is to help build the body. If carbohydrates and fat are present with protein, the former supply energy and allow the protein to perform its more important function of body-building. There should always be enough carbohydrates and fat to furnish energy to the body, so that the protein can be used chiefly for body-building. In the growing period of youth or after a wasting disease, it might seem that "flesh" could be "put on" by increasing the quantity of bodybuilding food. But such is not the case. The most effective work in building the body can be accomplished by using a normal amount of food rich in protein and a generous supply of foods rich in ash, carbohydrates, fat, and vitamines. With such a combination, the protein can be used to best advantage for body-building.

For practical purposes, the following general statement concerning the carbohydrates and fat requirement is believed to be adequate: If the total Calories and the number of Calories yielded by protein meet the requirement of a dietary standard and the food composing the diet is varied in composition, the carbohydrates and fat will exist in satisfactory proportion.

DAILY ASH REQUIREMENT.—Since ash is not a combustible foodstuff, it cannot be included in the foodstuffs whose energy requirement can be measured. Although ash exists in small quantity in food, the use of certain ash constituents is considered as necessary as the use of protein. A diet may meet the total energy, the protein, the carbohydrate, and the fat requirements, yet may be lacking in certain essential mineral materials. It is especially necessary to include food containing phosphorus, iron, and calcium in one's diet.

THE APPETITE AND FOOD REQUIREMENT.—The appetite is the most common measure of daily food requirement. If one relies upon his appetite as an index of the quantity of food he should consume, and if his health and weight remain normal, the appetite may serve as a guide for daily food requirement. But one may be a little over weight or under weight, and yet have normal body functions.

There can be no doubt, however, that the whims of the appetite often lead to unwise selection of food. A study of food composition is absolutely essential in overcoming this fault. Lack of energy or loss of flesh may be due to improper feeding. If the needs of the body and the kind and quantity of food that will supply these needs are understood by the home- keeper, she may do much in maintaining the health, happiness, and usefulness of the members of the family.

WEIGHT AS AN INDEX TO PROPER NOURISHMENT.—It has been found that the diet of an individual has a most decided effect upon his weight. Dr. Thomas D. Wood has prepared tables showing the normal height and weight of girls and boys of various ages. These tables are most valuable in determining whether or not a girl or boy is of the proper weight for his height. If the weight of a girl or boy is less than it should be, he is likely to be malnourished.

HEIGHT AND WEIGHT TABLE FOR GIRLS

HEIGHT 5 6 7 8 9 10 11 12 13 14 15 16 17 18 INCHES YRS YRS YRS YRS YRS YRS YRS YRS YRS YRS YRS YRS YRS YRS

39 34 35 36
40 36 37 38
41 38 39 40
42 40 41 42 43
43 42 42 43 44
44 44 45 45 46
45 46 47 47 48 49
46 48 48 49 50 51
47 49 50 51 52 53
48 51 52 53 54 55 56
49 53 54 55 56 57 58
50 56 57 58 59 60 61
51 59 60 61 62 63 64
52 62 63 64 65 66 67
53 66 67 68 68 69 70
54 68 69 70 71 72 73
55 72 73 74 75 76 77
56 76 77 78 79 80 81
57 81 82 83 84 85 86
58 85 86 87 88 89 90 91
59 89 90 91 93 94 95 96 98
60 94 95 97 99 100 102 104 106
61 99 101 102 104 106 108 109 111
62 104 106 107 109 111 113 114 115
63 109 111 112 113 115 117 118 119
64 115 117 118 119 120 121 122
65 117 119 120 122 123 124 125
66 119 121 122 124 126 127 128
67 124 126 127 128 129 130
68 126 128 130 132 133 134
69 129 131 133 135 136 137
70 134 136 138 139 140
71 138 140 142 143 144
72 145 147 148 149

ABOUT WHAT A GIRL SHOULD GAIN EACH MONTH

Age Age 5 to 8 6 oz. 14 to 16 8 oz 8 to 11 8 oz. 16 to 18 4 oz 11 to 14 12 oz.

Weights and measures should be taken without shoes and in only the usual indoor clothes

CHILD HEALTH ORGANIZATION 156 Fifth Avenue, New York

Courtesy of Child Health Organization. Prepared by Dr. Thomas D. Wood.

HEIGHT AND WEIGHT TABLE FOR BOYS

HEIGHT 5 6 7 8 9 10 11 12 13 14 15 16 17 18
INCHES Yrs Yrs Yrs Yrs Yrs Yrs Yrs Yrs Yrs Yrs Yrs Yrs Yrs Yrs

39 35 36 37 40 37 38 39 41 39 40 41 42 41 42 43 44 43 43 44 45 46 44 45 46 46 47 45 47 47 48 48 49 46 48 49 50 50 51 47 51 52 52 53 54 48 53 54 55 55 56 57 49 55 56 57 58 58 59 50 58 59 60 60 61 62 51 60 61 62 63 64 65 52 62 63 64 65 67 68 53 66 67 68 69 70 71 54 69 70 71 72 73 74 55 73 74 75 76 77 78 56 77 78 79 80 81 82 57 81 82 83 84 85 86 58 84 85 86 87 88 90 91 59 87 88 89 90 92 94 96 97 60 91 92 93 94 97 99 101 102 61 95 97 99 102 104 106 108 110 62 100 102 104 106 109 111 113 116 63 103 107 109 111 114 115 117 119 64 113 115 117 118 119 120 122 65 120 122 123 124 125 126 66 125 126 127 128 129 130 67 130 131 132 133 134 135 68 134 135 136 137 138 139 69 138 139 140 141 142 143 70 142 144 145 146 147 71 147 149 150 151 153 72 152 154 155 156 157 73 157 159 160 161 162 74 162 164 165 166 167 75 169 170 171 172 76 174 175 176 177

ABOUT WHAT A BOY SHOULD GAIN EACH MONTH

AGE AGE 5 to 8 6 oz 12 to 16 16 oz 8 to 12 8 oz 16 to 18 8 oz

Courtesy of Child Health Organization Prepared by Dr Thomas D Wood

Dr. Wood's tables also indicate the proper rate of increase in weight. The rate of increase in weight is thought to be quite as important as is the correct proportion between weight and height. The use of scales in the home and school is to be recommended. They furnish a means of determining whether the proper amount is being eaten.

QUESTIONS

Compute the energy requirement of at least two members of your family.
Compute your own energy requirement from this table.

Determine your height and weight. How does your weight compare with the normal weight given in the table for one of your height? If you are under weight, discuss with your teacher the kind and quantity of food needed to increase your weight. At the end of a month, again determine your weight. How does the gain compare with that given in the table for one of your age?