Is it true that "one man's meat is another man's poison?" Is water one man's poison and food another's? Is calcium? Is phosphorus? Is sodium? No one makes such absurd claims, yet the foods that are said to be boons to one man and banes to another never enter the blood stream as whole foods. They are broken down in the process of digestion and enter the blood as amino acids, monosaccharides, fatty acids, minerals and vitamins. Little fish never swim around in the blood streams of fish eaters. Potatoes are not rolled through the arteries and veins like marbles.

It is protested that "we are not all constituted alike." But physiologists have not found evidence that life is as chaotic as this implies. We each start life as a fertilized ovum, pursue the same course of orderly evolution, are born with the same number and kinds of organs and with the same functions. We possess the same glands and the same digestive systems. We are composed of the same chemical elements in the same proportions. Each of us secretes the same number and kinds of digestive juices and the same digestive enzymes. Structurally and functionally, our digestive systems are so much alike that the physiologists cannot find that different constitution we hear so much about. Everything points to the conclusion that we are constituted upon the same principles, are constructed alike, have the same nutritive needs and are equipped to digest and utilize the same kinds and classes of foods.

No man has the constitution of the dog or the cow. All men have human constitutions. No one ever proclaimed that cows are so differently constituted that while some of them live well on grasses and herbs, others must have flesh-foods. No one pretends that while most lions live on flesh, blood and bones, some lions are so constituted that flesh is their poison and they must graze like an ox.

What is constitution? It is the composition of the body. It is the tout ensemble of organs and functions that constitute the body. Every organ and every function in the body of one man is subject to the same laws as are the organs and functions of the body of any other man. The laws of nature do not require one kind of practice in one man and another and opposite kind of practice in another man. Habits and circumstances that are precisely adapted to the laws of life in one man are practices and circumstances that are precisely adapted to the same laws in another man.

Because of this false doctrine that there are many kinds of human constitutions, requiring different habits and circumstances to conform to the laws of life, we are misled into all kinds of errors. "Tobacco does not harm my constitution" says one, while another confidently asserts that "coffee agrees with my constitution." Another possesses a constitution that requires large quantities of food, while another is so constituted that he requires very little sleep. There is hardly an injurious practice and indulgence in the whole long catalogue of man's abuses of himself, that is not defended by those who practice them, or indulge, on the ground that it agrees with their particular and peculiar constitution. None of them, so far as I have been able to ascertain, have ever found that jumping from the top of the Empire State Building agrees with their constitutions. But if life is as chaotic as they seem to think, there seems to be no reason why some constitutions should not be found that would need and require such jumps.

Life being what it is and natural laws being what they are, what is really and permanently best for one is best for all; and what is injurious for one, is so for all.

None of the above is to be interpreted to mean that human needs do not vary under different conditions and circumstances of life. No one would be foolish enough to declare that the three days old infant and the fifty years old man have identical needs; or that the needs of man in the tropics and his needs in frigid regions are identical. Nor are the needs of the sick and those of the healthy identical. This is not due to any change in the law, but to change in conditions. The same man has different needs under different conditions.

There are individual weaknesses and differences in resistance that call for temporary modifications of any program of living, but it is essential that the modifications comply with the laws of life. All programs or parts of programs that violate these laws are ultimately ruinous. Variations within the law are legitimate. No variations that step outside the law are ever permissible.