Gender Differences in Metabolism

Biological differences between men and women affect metabolism and weight loss.
Gender Differences in Metabolism

Is it true that men can eat more than women without gaining weight and also lose weight faster? Yes, and the reason can be found in biological differences between men and women.

Metabolism Differences
There are relatively small metabolic differences between men and women. On average, women's total energy expenditure, which is the number of calories burned for metabolic needs, including breathing, blood circulation, digestion and physical activity, is around 5 to 10 percent lower than men's.1 The reduced energy expenditure can be partly explained by body composition.

Body composition, that is the amount of muscle, bone and fat that make up the body, are quite different between men and women. Men, in general, have more muscle mass, heavier bones and less body fat than women. For example, a typical man in his twenties who weighs 154 pounds, has 69 pounds of muscle, 23 pounds of bone and 23 pounds of fat. A typical women of the same age who weighs 125 pounds, has 45 pounds of muscle, 15 pounds of bone, and 34 pounds of fat. The recommended percentage of body fat for a woman is between 20 to 30 percent which is thought to be higher for childbearing, while the recommended range for a man is between 12 to 20 percent.2 Because of these differences in muscle mass, men burn more calories than women at rest.

Physical activity differences appear to also play a role. Women, in general, tend to be less active than men. One study that measured metabolism in both men and women found that the main reason women's energy expenditure was lower was due to significantly less calories burned from physical activity.3

These two factors—more calories burned at rest and more calories burned during activity—make it easier for men to eat more without gaining weight and also to lose weight faster than women of a similar size. The differences in terms of total weight loss, however, are modest. For example, in two 12-week weight-loss studies, one in men, and the other in women, the men lost 17.6 pounds, while the women lost 13.4.4,5

Bottom Line
While gender differences in metabolism do exist, the differences in terms of total weight loss are modest. For both men and women, making positive lifestyle changes will result in successful, lasting weight loss.

This content is reviewed regularly. Last updated June 25,2012.

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1 Ferraro R, Lillioja S, Fontvieille AM, Rising R, Bogardus C, Ravussin E. Lower sedentary metabolic rate in women compared with men. J Clin Invest. 1992 Sep;90(3):780-4.

2 Abernathy RP, Black DR. Healthy Bodyweights: an alternative perspective. Am J Clin Nutr 1996; 63(suppl):448S-451S.

3 Carpenter WH, Fonong T, Toth MJ, Ades PA, Calles-Escandon J, Walston JD, Poehlman ET. 1998. Total daily energy expenditure in free-living older African-Americans and Caucasians. Am J Physiol 274:E96-E101.

4 Ross R, Dagnone D, Jones PJ, Smith H, Paddags A, Hudson R, Janssen I. Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men. A randomized, controlled trial. Ann Intern Med. 2000 Jul 18;133(2):92-103.

5 Rippe JM, Price JM, Hess SA, Kline G, DeMers KA, Damitz S, Kreidieh I, Freedson P. Improved psychological well-being, quality of life, and health practices in moderately overweight women participating in a 12-week structured weight loss program. Obes Res. 1998 May;6(3):208-18.