38 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



weight and are thin and well trained down. In view of the experience 

 of the German nation, it seemed feasible to alter experimentally the 

 food intake and in consequence probably alter the nutritional level. 



It was first thought that such a study could be made with a group of 

 men who had already considerably reduced their body-weight by 

 dietetic alterations. Athletes who had suddenly lost much flesh in 

 preparation for an athletic contest were first considered, but it was 

 decided that athletes are trained not only to lose flesh but at the same 

 time to retain their excessive strength. Dr. George P. Denny, who 

 was at this period a collaborator at the Nutrition Laboratory, then 

 offered to secure the services of a number of coxswains from the boat 

 crews of Harvard University. Such men should be well suited for 

 observations of this kind, as it is necessary for them to train down to a 

 low body-weight, but at the same time no special strength is required in 

 their duties. Simultaneously with the inception of this project, war 

 was declared between the United States and Germany and the athletic 

 plans of Harvard University were entirely revolutionized. It was 

 therefore necessary to give up the idea of a research with coxswains and 

 seek elsewhere for the ideal subjects for the contemplated study. It 

 was finally decided to secure a number of normal individuals and study 

 the metabolism during a long period of low food intake. 



GENERAL PLAN OF RESEARCH. 



To have such a study of direct practical value, these men must be 

 living normal lives and carrying out their regular activities in the 

 community. Furthermore, they should be of normal weight, rather 

 than obese, to avoid introducing the pathological factor of obesity.^ In 

 Germany there was at first a somewhat acute period of loss in weight, 

 caused by the sudden stringency in food materials and the inability of 

 the people as a whole to adjust themselves rapidly to the lowered food 

 intake. There was then a period in which the redistribution of food 

 made it possible to hold the body-weight at the lower level. Our study 

 with the group of normal men was therefore made along two definite 

 lines, i. e., to determine the physiological effect of a pronounced reduc- 

 tion in diet under the following conditions: 



(a) During the period of loss in weight when the energy of the diet would be 

 supplemented to a considerable extent by drafts upon body material. 



(h) Dm-ing the period of subsequent feeding with a diet selected to maintain 

 the body in equiUbrium at the lower body-weight. 



During such weight reduction previous experience with fasting men 

 had shown that there would be in all probability a loss in nitrogen, 

 certainly a loss in body-fat, and probably a somewhat lower heat out- 

 put. Hence it was recognized that the following special records should 

 be made : 



First, the total caloric intake of each individual should be obtained, both 

 during the period of loss in weight and especially during the period of mamte- 

 nance at the lower body-weight. 



