624 VI. OCCURRENCE OF LIPIDS IN THE ANIMAL 



the supply of ingested calories exceeds the quantity of outgoing calories. A 

 situation of this nature may be associated with an excessive appetite, with 

 disturbances of the endocrine glands, or with certain metabolic disorders 

 which result in the conversion of an abnormally large amount of the food- 

 stuffs into fat. The subject of obesity was reviewed in 1944 by Newburgh 494 

 from the standpoint of energy metabolism, and by Conn, 495 who considered 

 the biological aspects. Pennington 496 suggested that the simple "over- 

 feeding" hypothesis of obesity should be replaced either by one which attri- 

 butes this condition to psychic stress exerted upon the hypothalamus by 

 way of the autonomic nervous system, as suggested by Waife, 497 or by the 

 hypothesis of the so-called "lipophilia" 498 (tendency of adipose tissue to 

 accumulate fat) . Since the same reduction in metabolism obtains in obese 

 individuals subjected to undernutrition as is the case with normal indivi- 

 duals on low-caloric diets, Pennington 499-501 is of the opinion that the treat- 

 ment of obesity should involve a decrease in dietary carbohydrate which will 

 result in reducing excessive energy stores; this would allow a weight re- 

 duction without any decline in energy expenditure, and without the need 

 for caloric restrictions. 



a. Obesity Resulting from Overconsumption of Foodstuffs. New- 

 burgh 494 defines obesity as the condition in which the body contains an ab- 

 normally large amount of adipose tissue. This excessive fat may be evenly 

 distributed, or may be localized in one or more discrete, encapsulated mas- 

 ses. The latter condition is referred to as "lipomatosis." Most investiga- 

 tors regard excessive caloric intake as the primary cause of obesity. Al- 

 though, in many cases, the overconsumption is voluntary, the continuation 

 of this practice over an extended period is, in all probability, based upon cer- 

 tain well-defined physiologic principles. The consumption of high- 

 carbohydrate diets results in an increase in insulin production. This 

 brings about an efficient storage of the excess foodstuff in the form of glyco- 

 gen and fat. However, it results in a concomitant rapid depression in 

 blood sugar, and the resulting hypoglycemia constitutes a stimulus to the 

 ingestion of additional food, which again stimulates the production of more 

 insulin. As early as 1924, Bulatao and Carlson 502 proved that changes in 



494 L. H. Newburgh, Physiol. Revs., 24, 18-31 (1944). 



495 J. W. Conn, Physiol. Revs., 24, 31-45 (1944). 



496 A. W. Pennington, /. Clin. Nutrition, 1, 100-106 (1953). 



497 S. O. Waife, Am. Practitioner, 2, 47-50 (1947). 



498 J. Bauer, Arch. Internal Med., 67, 968-994 (1941). 



499 A. W. Pennington, Delaware State Med. J., 23, 79-86 (1951). 

 600 A. W. Pennington, /. Clin. Nutrition, 1, 343-348 (1953). 



501 A. W. Pennington, Am. J. Digestive Diseases, 20, 268-274 (1953). 



502 E. Bulatao and A. J. Carlson, Am. J. Physiol., 69, 107-115 (1924). 



