British Journal of Nutrition

Review Article

Sex differences in fat storage, fat metabolism, and the health risks from obesity: possible evolutionary origins

Michael L. Powera1a2 c1 and Jay Schulkina1a3

a1 Research Department, American College of Obstetricians and Gynecologists, Washington DC, 20024, USA

a2 Nutrition Laboratory, Smithsonian National Zoological Park, Washington DC, 20008, USA

a3 Departments of Physiology and Biophysics, and Neuroscience, Georgetown University School of Medicine, Washington DC, 20007, USA

Abstract

Human beings are susceptible to sustained weight gain in the modern environment. Although both men and women can get fat, they get fat in different ways, and suffer different consequences. We review differences between men and women in the incidence of obesity, fat deposition patterns, fat metabolism, and the health consequences of obesity, and examine potential evolutionary explanations for these differences. Women generally have a larger proportion of body mass as fat, and are more likely to deposit fat subcutaneously and on their lower extremities; men are more likely to deposit fat in the abdominal region. Excess adipose tissue in the abdominal region, especially visceral fat, is associated with more health risks. Women have higher rates of reuptake of NEFA into adipose tissue; however, they also have higher rates of fat oxidation during prolonged exercise. Oestrogen appears to underlie many of these differences. Women bear higher nutrient costs during reproduction. Fat and fertility are linked in women, through leptin. Low leptin levels reduce fertility. Ovarian function of adult women is associated with their fatness at birth. In our evolutionary past food insecurity was a frequent occurrence. Women would have benefited from an increased ability to store fat in easily metabolisable depots. We suggest that the pattern of central obesity, more commonly seen in men, is not adaptive, but rather reflects the genetic drift hypothesis of human susceptibility to obesity. Female obesity, with excess adiposity in the lower extremities, reflects an exaggeration of an adaptation for female reproductive success.

(Received April 25 2007)

(Revised August 31 2007)

(Accepted September 21 2007)

(Online publication November 01 2007)

Correspondence:

c1 Corresponding author: Dr Michael L. Power, fax +1 202 554 4346, email mpower@ACOG.ORG

Footnotes

Abbreviations: 11β-HSD1, 11β-hydroxysteroid dehydrogenase type 1