The Physiology of Food And Economy in Diet

es .500iS'oo2OOOTotal Energy Value, 3300 calories Of course, the energy value must be greater if more work is done, and conversely : so that we may have such figures as these? Light work . 3000 calories Moderate work . 3500 ,, Heavy work . 4000 or more calories Since part of our food is consumed for the purpose of maintaining the body temperature, in cold weather the total calorie requirement is greater than in hot weather. Thus, according to Langworthy (1908), the average energy value of the diet of the Egyptian labourer is 2825. In the Tropics, indeed, where the external temperature may be higher than that of the body, it would clearly be of advantage if no heat were produced. But the machinery, as a whole, is not of the high degree of efficiency required for this to be the case. Heat, therefore, must be got rid of, chiefly by evaporation of sweat, but the actual production tends to be kept as low as possible by reduction of unnecessary muscular work. It may be noticed that chief stress seems to be laid in diet tables on the energy or calorie value of the food. This is justified by the fact, already mentioned, that, if anyreasonable kind of combination of foodstuffs be consumed, it will be found that, if taken in the amount necessary to afford the energy value, sufficient protein will be contained in it without further addition. Natural foodstuffs, even potatoes, contain more protein than is often supposed to be the case. Pure products extr...