|0.28| 0.99 | 3520 | 5.8
Man with active muscular work | 0.33 |0.33| 1.10 | 4060 | 5.6
Man with hard muscular work | 0.39 |0.55| 1.43 | 5700 | 6.9
==========================================================================

In the table it will be seen that the quantity of nutrients increases
with the labor to be performed. In order to secure the necessary heat
and energy, rations for men at heavy labor contain proportionally more
fat and carbohydrates than are required for light work. All dietary
standards, however, should be regarded as tentative only. Opinions
differ greatly on different points; for example, as to the amount of
protein a ration should contain. This is a matter that can be determined
only from extended investigations under a variety of conditions, and as
yet results are too meager to formulate other than tentative standards.
Chittenden has found that the body can be sustained on very much less
protein than is called for in the standard ration.[77] The amount of
protein in the ration should be ample to sustain the body weight and
maintain a nitrogen equilibrium; that is, the income and outgo of
nitrogen from the body should be practically equal.

[Illustration: FIG. 58.--DIETARIES AND DIETARY
STANDARDS.

(From Office of Experiment Stations Bulletin.)]

"While one freely admits that health and a large measure of
muscular strength may be maintained upon a minimum supply of
protein, yet I think that a dispassionate survey of mankind will
show that races which adopt such a diet are lacking in what, for
want of a better word, one can only describe as energy." [28]

On the other hand, excessive and unnecessarily large amounts of protein
are sometimes consumed, adding greatly to the cost of the ration and
necessitating additional labor on the part of the body for its
elimination.

247. Number of Meals per Day.--Some persons advocate two meals per day
rather than three, but dietary studies show that the best results are
secured when the food is divided among three rather than two meals, and
with a two-meal system the tendency is to consume a larger total amount
of food than when three meals are eaten. It is not essential that the
food be equally divided among the three meals. Any one of them may be
lighter or more substantial as the habits and inclinations of the
individual dictate. If it is found necessary to reduce the total
quantity of food con