The Effect of Overfeeding on Two Fat Young Women.

As obesity is a common disease and its consequences may be serious, it is surprising how seldom the processes by which it arises have been studied experimentally in man. We know of only five human subjects who have been overfed for a significant length of time while attempts were made to assess the weight gain against measured differences between the calorie intake in the food and the calorie expenditure during daily activity (Gulick, 1922; Wiley & Newburgh, 1931 a, b; Passmore, Meiklejohn, Dewar & Thow, 1955 a, b). All five of these subjects were thin men. Only one of these men, to whom Wiley & Newburgh gave an excess of 1680 kcal/day for 15 days, gained weight easily: he put on 4-4 kg, with a calorie value of 5-7 kcal/g weight gained. Gulick, who studied himself, gained weight easily for the first 16 days, but on a smaller calorie excess, Thereafter his gains were slow and the calorie value of the tissue laid down was always higher than that observed in Wiley & Newburgh's subject. The three thin men to whom Passmore et al. (1955a, b) gave an excess of about 15mkcal/ day for 2 weeks only gained weight slowly and at a cost of over 8 kcal/g. In this paper we record observations on overfeeding two fat women. They gained weight easily for 9 days, putting on 2.86 and 2.58 kg respectively at costs of only 2.5 and 4.0 kcal/g. The paper records a full analysis of their energy balances and the changes in their body composition.