One of the commonest dietary superstitions of the day is a belief in instinct as a guide to dietary excellence ... with a corollary that the diets of primitive people are superior to diets approved by science ... [and even] that light might be thrown on the problems of human nutrition by study of what chimpanzees eat in their native forests. ... Such notions are derivative of the eighteenth-century fiction of the happy and noble savage.

The growth curves of the famous Hopkins' rats are familiar to anyone who has ever opened a textbook of physiology. One recalls the proud ascendant curve of the milk-fed group which suddenly turns downwards as the milk supplement is removed, and the waning curve of the other group taking its sudden milk-assisted upward spring, until it passes its fellow now abruptly on the decline. 'Feeding experiments illustrating the importance of accessory factors in normal dietaries', Jour. Physiol., 1912, xliv, 425, ranks aesthetically beside the best stories of H. G. Wells.

There is no existing ‘standard of protein intake’ that is based on the sure ground of experimental evidence. ... Between the two extremes of a very high and a very low protein intake it is difficult to prove that one level of intake is preferable to another. ... Physiologists, in drawing up dietary standards, are largely influenced by the dietary habits of their time and country.