It may easily be shown that most of all the hardships which the civilized world is suffering as regards food supply is due to lack of understanding and of foresight.
The fundamental error is the popular faith in the high protein ration. The physiologists are at least partly at fault. Liebig's dictum, which made protein the essential food factor in supporting work, has misled the whole civilized world for more than half a century. The dietaries of institutions, armies, whole nations have been based upon a conception which modern science has shown to be utterly false, and the result has been an economic loss which staggers belief, and a destruction of human life and efficiency which overshadows every other malign influence.
To properly appreciate the place of nuts in the national dietary we must have in mind a clear conception of the nature of food as revealed to us in the light of modern laboratory studies of human nutrition and metabolism.
Food is to an animal what soil is to a plant. It is the soil out of which we grew. What we eat today is walking around and talking tomorrow. The most marvelous of miracles is the transmutation of common foodstuffs into men and women, the transfiguration of bread, potatoes and beefsteak into human intelligence, grace, beauty and noble action. We read in holy writ how the wandering Israelites were abundantly fed in the Assyrian desert with manna from the skies and marvel at the Providence which saved a million souls from death, forgetting that every harvest is a repetition of the same miracle, that each morsel of food we eat is a gift of Heaven conveyed to us by a sunbeam. Food is simply sunshine captured by the chlorophyll of plants and served up to us in tiny bundles called molecules, which, when torn apart in our bodies by the processes of digestion and assimilation release the captured energy which warms us with heat brought from the sun and shines out in human thought and action.
It is less than a century since Liebig and Lehmann and their pupils began to unravel the mystery of food. In recent years no subject has received more assiduous attention from scientific men, and none has been made the object of more constant or more profound research than the questions of food and food supply. The feeding of animals and men is without question the most pressing and vital of all economic problems.
The labors of Voit and Pettenkofer, Rubner, Zuntz, Atwater, Benedict, Chittenden, Mendel, Lusk and Hindhede have demonstrated that there is the closest relation between food supply or food selection and human efficiency. In fact, it has been clearly shown that the quality of the food intake is just as directly and as closely related to the question of human efficiency as is the quality and quantity of gasoline to the efficiency of an automobile.
In fact it has been established as a fundamental principle in human physiology that food is fuel. Life is a combustion process.
The human body is a machine which may be likened to a locomotive—it is a self-controlling, self-supporting, self-repairing mechanism. As the locomotive rushes along the iron road, pulling after it a thousand-ton cargo of produce or manufactured wares or human freight sufficient to start a town or stock a political convention its enormous expenditure of energy is maintained by the burning of coal from the tender which is replenished at every stopping place. The snorting-monster at the head of the rushing procession gets hungry and has to have a lunch every few miles along the way. After a run of a hundred miles or so the engine leaves the train and goes into a roundhouse for repairs; an iron belt has dropped out or a brass nut has been shaken off. Every lost or damaged part of the metal leviathan is replaced, and then it is ready for another century run.
The human body is wonderfully like the locomotive. It pulls or carries loads, it expends energy, it consumes fuel and has to stop at meal stations to coal up; it has to go off duty periodically for repairs. The body needs just what the locomotive needs—fuel to furnish energy and material for repair of the machinery.
Food differs from fuel chiefly in the one particular, that in each little packet of food done up by Mother Nature there is placed along with the fuel for burning a tiny bit of material to be used for repair of the machine. In other words, food represents in its composition both the coal and the metal repair materials of the locomotive. The starch, sugar and fat of foods are the coal and the protein or albumin is the metal repair stuff. Here we see at once the reason why starch and sugar and fat are so abundant in our foodstuffs, while protein or albumin is in quantity a minor element.