The National Institutes of Health has spent a total of $3.5 million to research why 75 percent of lesbians are obese.

One aspect of the study was to determine why homosexual men typically have healthier body weights compared to homosexual women. Thus far, the study has revealed that gay men have a "greater desire for toned muscles" than heterosexual men. One paper on the research noted that lesbian women tended to have lower "athletic self-esteem," which could contribute to unhealthy body weights, the Washington Free Beacon reported.

S. Bryn Austin, the project's lead investigator, said in a paper he co-authored that there were "no sexual orientation differences in odds of being muscle-concerned."

"Latent transition analyses revealed that sexual minority males (i.e., mostly heterosexual, gay, and bisexual) were more likely than completely heterosexual males to be lean-concerned at ages 17-18 and 19-20 years and to transition to the lean-concerned class from the healthy class," according to the paper. Austin is an associate epidemiologist at Brigham and Women's Hospital and pediatrics professor at Harvard Medical School.

The paper also said that men of all sexual orientations were at risk for negative body images.

"Both heterosexual and sexual minority males are at risk for presenting body image concerns and weight- and shape-related behaviors that may have deleterious health consequences," the paper said. "Results suggest the need for screening for concerns and behaviors related to leanness and muscularity in early adolescence among all males, regardless of sexual orientation."

There has not been any more information as to why lesbians tend to have higher obesity rates than their straight counterparts.

The project just received a $658,485 grant, making its funding total $3,531,925 at the start of its fifth year.