Study shows free online weight loss program improves outcomes

An analysis of a free online weight loss program revealed that members who were more active on the website lost more weight than members who were less active, report researchers at The University of Texas Health Science Center at Houston (UTHealth) Medical School.

The study in the Journal of Medical Internet Research focused exclusively on members of SparkPeople.com, America's largest diet and fitness site by unique visitors, according to comScore, an Internet technology company.

Lead researcher Kevin Hwang, M.D., M.P.H., of the UTHealth Medical School and his colleagues analyzed a variety of factors and found that the frequency of weigh-ins and the number of posts on the program's message boards were associated with significant weight loss.

Members who entered their weight at least four times a month lost 11 pounds per month more than those who did not, regardless of the duration of their membership. Likewise, members who posted at least one message on a message board lost more than 3 pounds more than those who did not.

Hwang said that they considered the possibility that "members made weight entries only when they were losing (rather than gaining) weight," but found that 71 percent of subjects in the study posted at least one instance of weight gain.

"The findings suggest that, if used in a certain way, an online weight loss program can be effective in producing significant weight loss by helping people keep track of their weight," Hwang said. "Some people who want to lose weight but avoid a scale for weeks on end can be engaging in a form of denial that can hamper weight loss."

More than a third of adults in the United States are considered obese and many are turning to free online programs to shed unwanted pounds. In the study, the authors wrote, "Because this online program is free, scalable, and widely disseminated, the potential public health impact is significant."

The researchers started with a random sample of members who had at enrolled in SparkPeople during a three month period in 2008 and included all available follow-up data for these members through May 10, 2010. The final study sample included 1,258 members who had at least two weight entries and adequate data to allow complete analysis. Ninety one percent of the subjects studied were female and the average body mass index was 31.6.

Hwang and his colleagues report that to their knowledge this is the first analysis of a natural cohort of members of a free online weight loss community, so findings reflect the "real world" rather than a prospective research study in which members must meet strict enrollment criteria.