460 THE HUMAN BODY 



der the guidance of the appetite, manages to make its fuel con- 

 sumption balance its fuel need. 



Since only such fuel as is not oxidized is stored as fat we might 

 conclude that those people who show a tendency to lay on fat are 

 the ones who habitually overeat. But overeating from the stand- 

 point of the energy requirement of the Body is quite distinct from 

 overeating in the sense of throwing upon the digestive organs too 

 heavy a burden. It appears that most of us, particularly when not 

 exercising vigorously, eat more than is necessary for the require- 

 ments of the Body, and so our bodies accommodatingly burn up 

 the surplus rather than to store it. In those whose bodies refuse to 

 get rid of the surplus in this way there is a deposition of fat under 

 similar circumstances. The degree of vigor of the bodily oxida- 

 tions is in large measure an idiosyncrasy, and one which is trans- 

 mitted in heredity from generation to generation, hence the 

 tendency of certain families to be fleshy and of others to be spare. 

 Changes in environment or in habit of life seem often to affect the 

 oxidation vigor, and so to change the tendency of the Body toward 

 fat-formation. We all know persons who in middle life have 

 changed from a spare to a fleshy tendency or the reverse, in a very 

 striking way. 



The Treatment for Obesity is obviously to make the energy re- 

 quirement equal, or even exceed the fuel intake. Vigorous mus- 

 cular exercise accompanied by strict dietary limitation may pro- 

 duce the desired result, but the good effects continue only so long 

 as the flesh-reducing measures are persisted in. Exercise and 

 dieting are both conducive to good appetite, therefore as soon as 

 the treatment is relaxed a return to the former condition is vir- 

 tually inevitable. An ingenious treatment for obesity, and one 

 which appears to be effective, is based upon the observation 

 quoted in the paragraph on Mastication (Chap. XXVIII), that 

 prolonged chewing of the food diminishes the appetite and allows 

 one to conclude a meal with comfort when much less has been 

 taken than the ordinary individual would demand. Thus the 

 fuel intake may be reduced to the minimum energy requirement, 

 or for a time below this, without conscious self-denial. 



Source of the Body Fat. For a long time there was much dis- 

 cussion as to which of the three sorts of food-stuffs, proteins, 

 carbohydrates, or fats, is the source of the fat which is stored in 



