British Journal of Nutrition

Papers of direct relevance to Clinical and Human Nutrition

Deliberate overfeeding in women and men: energy cost and composition of the weight gain*

Gilbert B. Forbesa1, Marilyn R. Browna2, Stephen L. Wellea3 and Barbara A. Lipinskia4

a1 Department of Radiation Biology and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA

a2 Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA

a3 Department of Internal Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA

a4 Department of Dietetics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA

Abstract

1. Thirteen adult females and two males were overfed a total of 79–159 MJ (1900–38 000 kcal) during a 3-week period at the Clinical Research Center, Rochester. The average energy cost of the weight gain was 28 kJ (6.7 kcal)/g, and about half the gain consisted of lean body mass (LBM) as estimated by 40Kcounting.

2. A survey of the literature disclosed twenty-eight normal males and five females who had been overfed a total of 104–362 MJ (2500–87000 kcal) under controlled conditions: twenty-five of these had assays of body composition, and three had complete nitrogen balances.

3. When these values were combined with those from our subjects (total forty-eight), there was a significant correlation between weight gain and total excess energy consumed (r 0.77, P < 0.01) and between LBM gain and excess energy (r 0.49, P < 0.01). Based on means the energy cost was 33.7 kJ (8.05 kcal)/g gain and 43.6% of the gain was LBM; from regression analysis these values were 33.7 kJ (8.05 kcal)/g gain and 38.4% of gain as LBM.

4. Individual variations in the response could not be explained on the basis of sex, initial body-weight or fat content, duration of overfeeding, type of food eaten, amount of daily food consumption or, in a subset of subjects, on smoking behaviour.

5. The average energy cost of the weight gain was close to the theoretical value of 33.8 kJ (8.08 kcal)/g derived from the composition of the tissue gained.

(Received August 23 1985)

(Accepted January 13 1986)

Footnotes

* Supported by grants HD 18454, RR00044, and AM32562 from the National Institute of Health, and based on work performed under contract no. DE-AC02-76EV03490 with the Department of Energy, at the Department of Radiation Biology and Biophysics, University of Rochester; assigned report no. UR-3490-2479.

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