American Journal of Clinical Nutrition, Vol 33, 978-988, Copyright © 1980 by The American Society for Clinical Nutrition, Inc

ORIGINAL RESEARCH COMMUNICATIONS

The effect of 6 weeks of overfeeding on the body weight, body composition, and energy metabolism of young men

NG Norgan and JV Durnin

The effect of overfeeding on the body weight, body fat, water content, energy expenditure, and digestibility of energy and nitrogen was investigated over 42 days in six young men. The metabolic rates in standard situations of work and rest were determined. Energy intakes were apparently increased by 6.2 MJ/day and energy expenditure fell slightly by 0.3 MG/day during overfeeding. Fecal and urinary losses of energy were a similar proportion of the gross energy intake in control and overfeeding periods (8%). Metabolizable energy intakes calculated from food tables agreed well with values derived from digestibility measurements in the control period (mean difference = +2%) but not in the overfeeding period (+8%). The implications of this are discussed. Mean body weight gain was 6.0 kg, 10% of initial weight; mean fat gain was 3.7 kg and water gain 1.8 liter. There were considerable interindividual differences in the weight and fat gain for a given excess energy intake. Metabolic rates in standard tasks were 10% higher at the end of overfeeding but expressed as kilojoules per kilogram per minute were similar to control values. Mean energy gain (144 MJ = fat gain X 39 kJ/g) was less than excess energy intake even allowing for overestimation of intakes using food tables and increases in metabolic rate. Such a discrepancy is unlikely to be due to unmeasured increases in metabolic rate but could have arisen from errors in the calculation of the variables involved. In this study where moderate weight gains were achieved by overfeeding mainly fat, increases in metabolic rate appear to be associated with increased body size and tissue gain rather than a luxuskonsumption mechanism.

This article has been cited by other articles:

				M. Siervo, G. Fruhbeck, A. Dixon, G. R. Goldberg, W. A. Coward, P. R. Murgatroyd, A. M. Prentice, and S. A. Jebb Efficiency of autoregulatory homeostatic responses to imposed caloric excess in lean men Am J Physiol Endocrinol Metab, February 1, 2008; 294(2): E416 - E424. [Abstract] [Full Text] [PDF]

				L. J. Kruskall, W. W. Campbell, and W. J. Evans The Atwater Energy Equivalents Overestimate Metabolizable Energy Intake in Older Humans: Results from a 96-Day Strictly Controlled Feeding Study J. Nutr., August 1, 2003; 133(8): 2581 - 2584. [Abstract] [Full Text] [PDF]

				J. A Levine, S. J Schleusner, and M. D Jensen Energy expenditure of nonexercise activity Am. J. Clinical Nutrition, December 1, 2000; 72(6): 1451 - 1454. [Abstract] [Full Text] [PDF]

				C. Weyer, R. E. Pratley, A. D. Salbe, C. Bogardus, E. Ravussin, and P. A. Tataranni Energy Expenditure, Fat Oxidation, and Body Weight Regulation: A Study of Metabolic Adaptation to Long- Term Weight Change J. Clin. Endocrinol. Metab., March 1, 2000; 85(3): 1087 - 1094. [Abstract] [Full Text]

				J. A. Levine, N. L. Eberhardt, and M. D. Jensen Role of Nonexercise Activity Thermogenesis in Resistance to Fat Gain in Humans Science, January 8, 1999; 283(5399): 212 - 214. [Abstract] [Full Text]

				C. Bouchard and A. Tremblay Genetic Influences on the Response of Body Fat and Fat Distribution to Positive and Negative Energy Balances in Human Identical Twins J. Nutr., May 1, 1997; 127 (5): 943S - 943S. [Abstract] [Full Text] [PDF]

				R. L. Leibel, M. Rosenbaum, and J. Hirsch Changes in Energy Expenditure Resulting from Altered Body Weight N. Engl. J. Med., March 9, 1995; 332(10): 621 - 628. [Abstract] [Full Text] [PDF]

				Z Glick, R. Teague, and G. Bray Brown adipose tissue: thermic response increased by a single low protein, high carbohydrate meal Science, September 4, 1981; 213(4512): 1125 - 1127. [Abstract] [PDF]