292 
NATURE 
when work is performed. The addition for hard 
but not excessive work amounts to 1400 Calories. 
Consequently, to meet this expenditure, a work- 
ing-man must be provided with more food to keep 
up the income side of his energy balance-sheet, 
the additional amount required being determined 
’ by the severity of the work and the conditions 
under which it is performed. 
The Daily Food Ration. 
For an ordinary day’s work of eight hours in 
this climate, it is reckoned that a man of average 
weight should receive, in his daily food, from 
3200 to 3300 Calories of available energy. A 
woman requires somewhat less, namely, 0°8 of a 
man’s ration, or 2560 to 2640 Calories. 
The former is provided by a ration which sup- 
plies the following :— 
As eaten, As digested, Net 
grams grams Calories 
Protein ... ae sf BOO) ».000), ORE cet AUT 
Fat os we TOO! 2 NOPE |. SA3 
Carbohydrate 500 485 1988 
Total 3248 
It need scarcely be said that to make out a 
ration of this kind a table of food- and energy- 
values such as is exemplified in the following short 
list is needed :— 
Composition and Energy-value of Some 
Common Foods. 
Per cent. Per pound weight 
c e_e. c ————— 
Carbo- Carbo- Energy 
Protein Fat pydrates Protein, Fat, hydrate, value, 
grams Calories 
Beef (medium grams grams 
fat); sss MeertS'O), 18'0. "=" G8i0W AiG — 1039 
Mutton’. ©... 13°5 25:0. — | 6172 1109 — 1282 
Bacon(average) 9°5 59°4 — 43'0 270°0 — 2687 
Herring (edible 
portion) 195 7% — 884 32°2 — 652 
Bread@’:5). 5.0 (Bio a2. Weg) hg6s 54 238 1175 
Milk’ x2 1023) AO. Ua RYN ih 4 er aan eer 
Plage... fic. igeen Bar), gO, ees 54°4 43°! —= 624 
Cheese (full 
cream) ... '25°9. 33°7. 2°4 117°5 152°8° o'9 1950 
Oatmeal 16°E = ‘712 GY°5, |” 73°04). 92:0) 406%2" 3860 
Potatoes wohl 75) Ot 20a 7°94 0°46 95°3 427 
Peas (green)... 7°90 O°5 16°9 31°75 22°70 966 465 
Peas (dried) .. 24°70 1°5 60° 108°8 68 2722 1626 
Butter ro. 85:0 “= 4°5 384°5 — 3600 
Margarine 12 840 | — 54 381% — 3566 
Dripping 0°25 96°45 — I'l 4375 — 4068 
Allowance has also to be made for waste in 
food purchased, such as bone, gristle, surplus fat, 
etc., of meat; skin, rind, core, etc., of vegetables. 
Langworthy calculates that a ration of 3200 
Calories utilised corresponds to one of 3500 
Calories as eaten, and of 3800 Calories as pur- 
chased. 
The Foodstuffs and Energy-value of Three 
Ordinary Meals. 
The following gives an illustration of how the 
foodstuffs and food energy necessary for an 
average day’s work are distributed over three 
simple meals. But it is not to be understood that 
this is in any sense an ideal set of meals. 
NO. 2459, VOL. 98] 
[DECEMBER 14, 1916 
BREAKFAST. ak 
Food Protein, Fat, nee aad 
grams grams grams. Calories . 
Bacon, 2 oz. 5°37 33°75 _ 336 { } 
I egg es 6°55 5°40 —- 7 
Bread, 4 |b. 18°15 2°70 119‘0 588) 
Butter, 4 oz. O14 12°00 — 1 /LERe se 
Tea, sugar I oz., = 
milk 4 pint 2°40 2°80 32°0.) Sian 
Total 32°61 56°65 Isto 1281 
DINNER ‘i 4 
Beef, 4 lb. 34°00 40°80 — 519 
Potatoes, rlb. ... 7°90 0°46 95°26 427. 
Vegetables, 2 02.... 0°43 0°08 2°26 12, 
Bread, 2 oz. 4°53 0°65 30°00 147° 
Cheese, LP.Gz2 8 77580 8:50 0°70 rns 
Tapioca a aes 
GH07)) 3°30 3°20 28°20 159 
Total 57°26 53°69 156'42 1375 
SUPPER. 
Porridge (oatmeal, : 
Pio) 2) lami peg ieee UIT «2) 4:07. 38°30 232 
Bread, } 1b. 9'07 1°35 59°50 294 
Butter, 4 0z. O'l4 12700 = 112 
Milk, 4 pint 9'60 11°30 14°20 =. 203 
Jam, I oz. 0°20 0'03 14°10 59 
Total 28°11 28°75 126710 ‘900 
Total for 3 meals... 117°98 139°09 433°52 3556 
To be relished, foods must be appetising and 
well cooked, and if good digestion is to be secured 
and retained, the meals must not be hurried over. 
It is of the greatest importance, therefore, that 
attention be paid to the cooking and serving of 
meals, and that time be taken for their enjoyment. 
Human Efficiency. 
If the table of expenditure of energy by 
the human body be referred to, it will 
be seen that more is lost in the form of 
heat than in any other way. In fact, the propor- 
tion of the whole food energy which usually re- 
appears as useful work is only from 10 to 15 per 
cent. of the intake. This, it may be recalled, is the 
case also in the ordinary locomotive or other form 
of heat engine. The matter may, however, be 
looked at in another way. For mere maintenance 
at complete rest the human body requires an in- 
take of 2000 Calories, for maintenance at ease 
2400 Calories, and for hard work an extra intake 
is needed of 1400 Calories. Of this extra intake 
of energy—the price paid for work—4oo Calories 
(28°5 per cent.) ordinarily reappears as useful 
mechanical work, and would correspond to 170,000 
kilogram-metrés or 1,220,000 foot-pounds for a 
day’s work of eight hours, to a condition of 
moderate fatigue. The human body has the 
power, however, of working more economically 
when severe and prolonged strain is required. 
Under such conditions it has been ascertained 
that one-half or even more of the chemical energy 
of the additional food taken may reappear in the 
form of useful external work. The human 
machine, all things considered, is therefore a very 
“efficient? one when at work, though an expen- 
sive one to maintain in idleness. Wise coal 
