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Journal of Nutrition and Metabolism
Volume 2011, Article ID 391809, 6 pages
Review Article

Sex Differences in Energy Metabolism Need to Be Considered with Lifestyle Modifications in Humans

1St. George Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia
2Department of Medicine, St. George Hospital, Kogarah, NSW 2217, Australia

Received 1 March 2011; Accepted 3 May 2011

Academic Editor: Andrea Buchholz

Copyright © 2011 Betty N. Wu and Anthony J. O'Sullivan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Women have a higher proportion of body fat compared to men. However, women consume fewer kilojoules per kilogram lean mass and burn fat more preferentially during exercise compared with men. During gestation, women store even greater amounts of fat that cannot be solely attributed to increased energy intake. These observations suggest that the relationship between kilojoules consumed and kilojoules utilised is different in men and women. The reason for these sex differences in energy metabolism is not known; however, it may relate to sex steroids, differences in insulin resistance, or metabolic effects of other hormones such as leptin. When considering lifestyle modifications, sex differences in energy metabolism should be considered. Moreover, elucidating the regulatory role of hormones in energy homeostasis is important for understanding the pathogenesis of obesity and perhaps in the future may lead to ways to reduce body fat with less energy restriction.