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WORK AND FOOD REQUIREMENT. 937
It is certainly true that the amount of nutriment required by the body
is not directly proportional to the body weight, for a small body consume!
relatively more substance than a larger one, and varying quantities of
fat may also cause a difference; but a large body, which must maintain
a greater quantity, consumes an absolutely greater amount of substance
than a small one, and in estimating the nutritive need one must also
always consider the weight of the body. According to Voit, the diet
for a laborer with 70 kilos body weight requires 40 calories for each kilo.
Ekholm 1
calculates, basing it upon his experiments, that for a man
weighing 70 kilos, busied with reading and writing, the net calories are
24 .",0 and the gross calories 2700, or 35 and 38.6 calories per kilo. In the
ordinary sense for a resting man, the general food requirement is calculated
in round numbers as 30 calories for every kilo. The minimum figure
for metabolism during sleep and in as complete rest as possible has been
found by Sonden, Tigerstedt and Johansson 2
to be 24-25 calories.
As several times stated above, the demands of the body for nourish-
ment vary with different conditions of the body. Among these condi-
tions two are especially important, namely, work and rest.
In a previous chapter, in which muscular labor was spoken of, it was
seen that all foodstuffs have almost the same power of serving as a source
of muscular work, and that the muscles, it seems, select that foodstuff
which is supplied to them in the greatest quantity. As a natural sequence
it is to be expected that muscular activity requires indeed an increased
supply of foodstuffs, but no essential change in their relation as compared
to rest.
Still this does not seem to hold true in daily experience. It is a well-
known fact that hard-working individuals—men and animals—require
a greater quantity of proteins in the food than less active ones. This
contradiction, is however, only apparent, and it depends, as Voit has
shown, upon the fact that individuals used to violent work are more
muscular. For this reason a person performing severe muscular labor
requires food containing a larger proportion of proteins than an individual
whose occupation demands less violent exertion. Another fact is that
the diet rich in proteins is often concentrated and less bulky, and also
that in many cases of training, a diet yielding as little fat as possible is
selected.
If we compare the results for the needs of food in work and rest which
are obtained under conditions which can be readily controlled, it is found
that the above statements are in general confirmed. As example of this
1
Skand. Arch, f . Physiol., 11.
* Sonden and Tigerstedt, Skand. Arch. f. Physiol., 6; Johansson, ibid., 7; Tigerstedt,
Nord. Med. Arkiv. Festband., 1897.
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