332 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



evidence is, however, sufficiently extensive and the general trend is such 

 as to justify the conclusion that the ingestion of a diet containing a pre- 

 ponderance of fat has a distinct effect upon the metabolism, although 

 this was much less than that found with either protein or carbohydrate. 

 The findings are so irregular that it is probably unjustifiable to use the 

 single highest maximum value found, and we must therefore resort to 

 the average figure, which is not far from a maximum of 12 per cent. 



In the experiments with mixed diets, in which frequently the subject 

 took a sufficient number of calories in one meal to provide maintenance 

 for a man at severe muscular work the entire day, i. e., approximately 

 4,000 calories, the maximum increment reached 40 per cent or more. 



An absolute accuracy of 3 per cent in the measurement of the basal 

 metabolism on any given day is hardly obtainable. Furthermore, 

 variations in the body position have an effect upon the basal metabo- 

 lism. It has been shown that the basal value obtained with the subject 

 lying quietly without food in the stomach may be increased slightly by 

 having the subject sit upright in a chair. 1 On the other hand, Du 

 Bois 2 finds that with the subject sitting properly supported in a steamer 

 chair, the basal metabolism is not increased over that found with the 

 subject in the lying position and in certain instances it was even de- 

 creased. Standing upright has been found to increase the metabolism 

 approximately 10 per cent. 3 



The maximum effects obtained with carbohydrates, protein, and 

 mixed diets are, however, very considerably greater than those due to 

 ordinary changes of position. While one might state tentatively that 

 the increments with food, at least at the height of digestion, are such as 

 would be expected when man is performing light muscular work, the 

 inadequate definition of the term " light muscular work" is such as to 

 make this of little significance. Too little knowledge is available at 

 present regarding the increments in metabolism accompanying simple, 

 every-day customs; hence we find ourselves at a loss to compare the 

 increments for these food materials with those accompanying minor 

 muscular activity. 



The increments with food are certainly much less than those obtained 

 as a result of walking. On the other hand, since there is an increase in 

 both the respiration and the circulation, it is evident that the ingestion 

 of food and its effect upon metabolism are to be considered much more 

 broadly than as an increment in the gaseous metabolism. There is 

 unquestionably a stimulation in the muscular activity and general 

 muscular tonus, accompanied by a sense of increased vigor, which is 

 wholly out of proportion to the relatively small increase in the metab- 



and Riche, Am. Journ. Physiol., 1911, 27, p. 406. 

 'Soderstrom, Meyer, and E. F. Du Bois, Arch. Intern. Med., 1916, 17, p. 872. 

 'Benedict and Murschhauser, Carnegie Inst. Wash. Pub. No. 231, 1915. Benedict and Car- 



penter, Carnegie lust. Wash. Pub. No. 120, 1910. 



