Hereditary factors in body build

Abstract

Some physiologists of nutrition seem inclined to conclude that all obesity is exogenous or nutritional obesity; that any excess of energy of intake over what is required to maintain the temperature of the body, and to enable it to do its work, due allowance being made for loss in feces and urine, must be stored as body fat. That there are endogenous factors is shown in cases of hypothyroidism and disfunction of some other endocrine glands. But Van Noorden, for example, is inclined to reject heredity as a factor in obesity. It is, indeed, recognized that in some races and in some families the individuals have heavier body build than in others. Thus the Scotch are slender and the Greeks and Eastern Jews are stout. But the racial as well as the familial idiosyncracies in build he would explain on the grounds of what may be called social heredity i. e., the handing on of traditions of feeding. On the other hand the degree of functioning of the endocrine glands is hereditary.

To see if there are hereditary factors in build, a mass of between 2,000 and 3,000 sets of measurements of build, taken chiefly from random family records was distributed by the indices of build, and the number of individuals possessing each index was determined. This gives Figure 1. Figure 1 is the distribution of build of adults referred to about 50 years of age. These adults are grouped in five large classes: Very Slender, Slender, Medium, Fleshy and Very Fleshy. A similar polygon might be made persons 18 years of age, 14 years, 12 years, 8, 4, and 1 year or at birth. The means at these different years would vary—thus from 55 per cent.