While adding in-person group support sessions to a weight loss program produces the best results, adding just an online behavioral intervention can produce results nearly as good, at a much lower cost. Those are the findings from a 230-person trial from social wellness platform ShapeUp, recently published in the American Journal of Public Health.

“The findings of this study are significant in that they reveal substantial progress in identifying cost-effective, scalable, online behavioral weight loss interventions that are capable of significantly improving outcomes,” Dr. Rajiv Kumar, founder and CEO of ShapeUp and one of the co-authors of the study, said in a statement. “At ShapeUp, we believe that combining social support with evidence-based health interventions is a recipe for sustainable behavior change, and this study strengthens our conviction.”

All of the study's subjects participated in ShapeUp Rhode Island (SURI) 2011, a 3-month competition-driven weight loss program. Participants competed in teams and received a pedometer and access to a website where they could report their daily physical activity, weight loss, or both. One arm of the study was involved only in SURI. 

The second arm added an online behavioral intervention on top of their participation in SURI. These participants were given goals for weight loss, calorie intake, and activity and were introduced to a web site that contained additional self-monitoring tools, 10-15 minute educational videos, and tips on cooking and meal planning. The third group had access to SURI, the online weight loss intervention, and optional, weekly in-person meetings covering the same topics as on the website.

Unsurprisingly, the third arm, with access to all three interventions, posted the best weight loss results: they had an average weight loss of 6.1 percent of total body weight and had 54.3 percent of members lose 5 percent or more -- an eight-fold increase over the SURI-only group, where only 6.5 percent of participants posted 5 percent weight loss. But the second arm also did well, with an average weight loss of 4.2 percent of total bodyweight, and 42.2 percent achieving a clinically significant 5 percent weight loss, an increase of sixfold over the SURI-only group.

Interestingly, the SURI-only group posted the best increase in physical activity, possibly owing to the fact that their intervention was focused entirely on activity, without strategies for reducing caloric intake.

Researchers calculated cost effectiveness by dividing the average weight loss of the intervention by the average per-person cost. Based on this formula, the first two arms, SURI and SURI plus online behavioral intervention, were about the same in terms of cost-effectiveness, but significantly better than the group sessions which, while effective, also presented a significant additional cost.

Demographically, most of the participants in the study were white women, but this is also in line with the demographic breakdown of ShapeUp programs, according to researchers. Regardless of intervention group, younger people were less engaged with the program and posted worse weight loss results.

Finally, researchers found that in all three groups, regardless of intervention, weight loss results dropped off after completion of the program. At the 12-month follow up, there was no statistical difference in weight loss between the three groups.