Obese women who start to lose weight will also see an improvement in the quality of their sex lives, according to a U.S. study recently released.

Even a moderate weight loss reduced complaints of feeling sexually unattractive and led to improved desire, according to the study presented at the annual meeting of The North American Association for the Study of Obesity (NAASO) in Vancouver.

"If people experience benefits and rewards from their weight loss and health efforts, it may motivate them to continue a healthy lifestyle," said Martin Binks, director of behavioral health at the Duke Diet and Fitness Center in Durham, North Carolina.

Researchers who tracked 161 obese women participating in a prescription weight loss program in Minnesota found almost two thirds reported problems with aspects of their sex life when the study began.

Within the first year, the percentage of women who said they had problems with sexual desire dropped to 15 percent from 39 percent and the number who felt they were sexually unattractive dropped to 26 percent from 68 percent.

The Minnesota weight loss program lasted for two years, but health officials said it was normal for the majority of the weight loss to be in the first year.

The researchers said they found similar results in a survey of 26 obese men in the Minnesota weight-loss program, but cautioned that the small number of male participants made it difficult to draw conclusions from that data.

Health officials say there has been a dramatic increase in obesity in North America in the past two decades, and 64 percent of adults in the United States are considered to be overweight or obese.