236 THE HUMAN MECHANISM 



750 grams (1 to li pounds) of lean meat, although of course 

 the protein is not all taken in the form of meat. On the 

 other hand, experiments have shown that men may live for 

 years in good health on a protein intake of from 40 to 

 50 grams daily without loss of protein from the body. 



If then an adult man can maintain puotein equilibrium on 

 from 40 to 50 grams of protein daily, but ordinarily con- 

 sumes two to three times this quantity, the question arises 

 whether the additional 50 to 100 grams are in any way 

 harmful. Many students of this subject have strongly taken 

 the position that such is the case, and there can be no 

 question that the health of many people, especially when 

 leading sedentary lives, has been greatly improved by re- 

 ducing the consumption of protein to 60 or 70 grams, or 

 even to 40 or 50 grams daily. To what is this improvement 

 due ? Is it because the handling of so much protein by the 

 adult is necessarily harmful ? (See p. 239.) 



23. Possible harm and possible advantage in an abundant 

 protein diet. We can readily see at least two ways in. which 

 the greater protein intake may be harmful. In the first place, 

 it involves greater danger of incomplete protein digestion in 

 the small intestine and the consequent delivery by peristalsis 

 of excessive amounts of protein to undergo microbic putre- 

 faction in the large intestine. In general the presence of a 

 decidedly offensive odor to the feces suggests that more pro- 

 tein 1 is being eaten than can be properly digested, and justi- 

 fies at least an experimental reduction in the protein of the 

 food. It must, however, be remembered that putrefactive 

 odors may be due to other causes than excessive protein 

 diet (impaired digestion of fats, for example) and, on the 

 other hand, there may be excessive putrefaction and yet the 

 feces have no very offensive odor because the compounds 

 responsible therefor have been destroyed within the body. 



1 The substances responsible for the offensive odor are almost entirely 

 derivatives of protein. 



