OBESITY 33 



Means and Woodwell discuss the comparative accuracy of the various 

 methods of calculating normal basal metabolism. They conclude that the 

 average deviation of the predicted from the actual metabolism is essen- 

 tially the same as calculated by the Du Bois height-weight chart, the 

 Harris-Benedict prediction tables, and the Dreyer body-weight formula, 

 and suggest that the Du Bois method be followed, since it is already in 

 common use. 



The Effect of Food on the Metabolism. The taking of food raises 

 the metabolism materially. The ingestion of protein in particular has 

 a very striking effect in this direction, which is called the specific dynamic 

 action of protein. Carbohydrates and fat have a similar, but lesser 

 effect. According to Magnus-Levy (&), the increase amounts to 17 per cent 

 of the caloric value of the food in the case of protein, 9 per cent for carbo- 

 hydrate, and 21/Q per cent for fat. The specific dynamic action of pro- 

 tein is very thoroughly discussed by Lusk(e), to whom we owe much of 

 our knowledge on this subject. The extra heat production on a mixed 

 diet amounts to about 14 per cent of the basal metabolism, so that this 

 much extra must be taken if the body is to be maintained in equilibrium 

 in a state of rest. 



Energy Requirements on Account of Work Performed. Muscular 

 exercise increases the metabolism more than any other factor. Thus it 

 has been found that moderate exercise increases it about three times, and 

 very severe exercise as much as nine times. It is usually stated that 

 a man requires about 36 calories per kilo if doing light work, and 

 from 45 to 50 calories per kilo if doing heavy work, or about 2500 calories 

 and 3500 calories respectively for a person weighing 70 kilos. 



Clinical Description of Obesity 



Obesity in general may be divided into two main groups, the exogenous 

 and the endogenous. 



Exogenous obesity is the ordinary form, in which the condition is 

 simply the result of an excess of intake over outgo in an otherwise healthy 

 organism. 



In the endogenous form there is usually, perhaps always, an altera- 

 tion of function of one or more of the endocrin glands, which appears 

 to be the cause, either directly or indirectly, of the obesity. In most 

 instances the basal metabolism has been found normal, in a few it has been 

 found definitely decreased. There is a theoretical possibility that an 

 endogenous form may exist independent of disease of the endocrins, 

 with lowered metabolism resulting from a primary lessened activity of 

 the body cells, but such a type has not been proved to exist. 



