THE PROTEIN REQUIREMENTS OF MANKIND 97 



value is not of such great importance as would be the case in 

 European dietaries. The reason for this is that tropical food, 

 being largely of a vegetable nature, any dietary that affords 

 a sufficiency of the protein element is very unlikely to be deficient 

 in carbonaceous material, but, indeed, will usually provide a 

 potential energy considerably in excess of the ordinary dietary 

 standard. 



In connection with the work on dietaries in India, except 

 where the potential energy is evidently of importance, we shall 

 limit our consideration of the subject to the protein element. 



There is just one aspect of carbon metabolism that we should 

 like to refer to at once, as it has impressed itself very urgently 

 on us whilst working with diets that provide a large fuel value, 

 such as the gaol dietaries of Bengal. The usually accepted state- 

 ments place the coefficient of carbohydrates absorption from 

 different foodstuffs very high as a rule, from 96 to 99 per cent. 

 This result is arrived at by comparing the loss of carbohydrate, 

 capable of being hydrolyzed into sugar, in the faeces with the 

 total quantity presented in the diet. Now the Bengal gaol diets 

 provide, in comparison with European standards, a very exces- 

 sive amount of carbohydrates, sufficient in most cases to raise 

 the energy metabolism to 60, or over 60, calories per kilo of 

 body weight. Apparently the large quantities of carbohydrate 

 matter necessary for this great heat value are practically all 

 absorbed, as only a very small percentage could be recovered 

 from the fseces. 



On thinking over the question how this great potential energy 

 is made use of by Bengali prisoners, we have experienced con- 

 siderable difficulty in accepting the customary explanation that 

 it leaves the body in the form of heat and mechanical work, or 

 is retained as fat. The ordinary working Bengali is a particu- 

 larly thin individual, decidedly wanting in body fat, and his 

 desire for, or capabilities of, muscular exertion are less than in 

 any other race with whom we have had to do. The large masses 

 of carbohydrate cannot, therefore, be burnt off in providing 

 energy for muscular exertion, neither can it be fixed and stored 

 in the body as fat. The demands for fuel for the maintenance 

 of body heat in a tropical country should not be anything like 

 so great as in colder climates ; and yet the accepted standard 

 for Europeans is from 40 to 45 calories per kilo of body weight, 

 whilst prisoners in Indian gaols are provided with 60 to 70 calories. 



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