554 VI. OCCURRENCE OF LIPIDS IN THE ANIMAL 



standard or ideal weight. Normal values have been established for dif- 

 ferent ages, height, and sex. The per cent deviation from the standard 

 can be expressed by the following equation 166 : 



M - M s 



A % « 100 



M s 



in which M is actual weight, M s is the standard weight, and A % gives 

 the extent of the deviation ; this latter value is positive in the case of over- 

 weight individuals and negative in those instances in which the body weight 

 is less than the predicted normal. The percentage deviation from normal 

 as expressed by relative weight (M R %), is obtained by the following ex- 

 pression : 



M 



Mb % = 100 jj£ 



However, neither of the above formulas takes into consideration the fact 

 that variations in weight may result from changes in composition of tissue 

 components other than fat. Even when evaluated with reference to the 

 size of the skeleton, body weight does not afford an accurate index of fat- 

 ness. This fact constitutes the fundamental limitation in the use of this 

 type of data for assessing the leanness or fatness of an individual. Keys 

 and Brozek 166 summarized in a comprehensive manner the limitations of 

 the standard weight method, as well as the results obtained by the employ- 

 ment of this technic. 



The best criteria for the indirect measurement of body composition 

 would appear to be anthropometric data, which include the determination 

 of subcutaneous fat deposits by making use of the skinfold technic or of 

 roentgengrams, the determination of body density, the estimation of total 

 water content, or the employment of the so-called fat-soluble indicators to 

 determine the fat content by dilution. Each of these procedures will be 

 described below. 



(6) The Use of Subcutaneous Fat Estimates. Since the subcutaneous 

 layer of adipose tissue constitutes an important proportion of the storage 

 fat, a physical measurement of this deposit can be used as an indirect 

 method for the estimation of the total depot fat. According to Wilmer, 167 

 the skin together with the subcutaneous fat layer comprises 17% of the 

 body weight of the adult man. This total can be divided into 6% for the 

 proportionate skin weight and 11.5% for that of the subcutaneous fatty 

 tissue. In the case of women, the weight of the skin is given as 6%, that of 

 the subcutaneous tissues as 23.7% of body weight. 



167 H. A. Wilmer, Proc. Soc. Exptl. Biol. Med., 48, 386-388 (1940). 



