APPETITE 123 



how much. Under ordinary conditions, however, the ap- 

 petite is for various reasons often misleading. Appetite 

 itself is a diffused sensation of discomfort, which is 

 caused partly by the failure of the tissues to receive 

 as much food as they need and partly by the failure 

 of the stomach to be adequately filled with the food 

 which it has been trained to expect. For the appetite 

 to be a reliable guide, it must be aroused only when 

 the tissues need food and the stomach needs filling. 

 If a person is habitually overeating, the stomach trained 

 to expect food at given intervals, gives the signal through 

 the appetite that it is time for more food, in spite of 

 the fact that the tissues do not need it and so must 

 store the excess as fat. If, on the contrary, a person 

 habitually eats too little, the stomach accustomed to ex- 

 pect and to take care of but small amounts, may fail 

 to produce the appetite for food, although the tissues 

 are actually in need of it. 



Its unreliability. Another factor which contributes 

 to the unreliability of the appetite is that it often out- 

 lives its cause and so leads to the taking of a larger 

 amount of food than is necessary. The stomach may 

 be filled sufficiently by a meal to satisfy the needs of 

 the tissues and yet the appetite persist, especially if 

 the food has been swallowed without much chewing. 

 If the appetite is further reinforced by pleasure in eat- 

 ing, the probability of overeating is greatly increased. 

 To avoid this, food should be eaten slowly, that the 

 appetite for it may tend to cease when enough has been 

 eaten. 



A third most important cause of an unreliable appe- 

 tite is eating between meals. This practice not only in- 

 terferes with the rest which the stomach needs but also 

 prevents the proper recurrence of appetite. When for 



