Women appear to be more accepting of their bodies/weight

"While women consistently report being more dissatisfied with their bodies than men as far as thinness is concerned, that dissatisfaction has decreased over the 31-year period we studied," said Bryan Karazsia, PhD, of The College of Wooster, who presented the research.

Body dissatisfaction is not only a common predictor of eating disorders, such as anorexia nervosa and binge eating, but also can play a role in the development of depression, said Karazsia. Research conducted in the 1990s suggested that the percentage of women who were unhappy with their weight was on the rise.

Karazsia and his colleagues conducted a meta-analysis of more than 250 studies representing 100,228 participants from 1981 to 2012, to analyze trends in how people felt about their bodies, specifically in regard to weight. They found that while women consistently were more dissatisfied than men, their dissatisfaction gradually declined over time, while men's dissatisfaction remained relatively constant throughout.

Because men's body image issues aren't always about thinness and can often be related to musculature, the researchers also conducted a similar meta-analysis, this time focusing on muscle size. They analyzed 81 studies representing more than 23,000 participants over a 14-year span. They found that men regularly reported more body dissatisfaction than women when it came to muscularity but, over time, levels remained relatively consistent for both men and women.

In both meta-analyses scores did not vary by geographic region or age.

While the results were not entirely unexpected, Karazsia said the findings were in some ways surprising.

"When we consider that humans in the United States, where most studies in our review were conducted, are physically larger than they have ever been, with more than two-thirds of U.S. adults being overweight or obese, one might expect that body dissatisfaction should be increasing. But we found the opposite," he said.

Karazsia is "cautiously optimistic" that the findings represent a positive change in the social pressures that women face toward more body acceptance and body diversity.

"The last two decades have witnessed increasing attention and awareness on a body acceptance movement aimed primarily at girls and women," said Karazsia. That, combined with increased media visibility of role models who run counter to the trend towards thinness, may, in part, help explain their findings.