Weight loss can be contagious, according to a new study that showed how teammates in a weight-loss competition significantly influenced each other’s weight loss.
Researchers from The Miriam Hospital’s Weight Control and Diabetes Research Center and The Warren Alpert Medical School of Brown University found that team members achieved similar weight-loss outcomes. Additionally, the participants who said their teammates played a large role in their weight loss actually lost the most weight.
“We know that obesity can be socially contagious, but now we know that social networks play a significant role in weight loss as well, particularly team-based weight loss competitions,” said lead author Tricia Leahey, Ph.D., of The Miriam Hospital and Alpert Medical School.
“In our study, weight loss clearly clustered within teams, which suggests that teammates influenced each other, perhaps by providing accountability, setting expectations of weight loss, and providing encouragement and support.”
She noted that online team-based weight-loss interventions are increasing in popularity as a way to encourage weight loss. The study examined the effects of teammates and social influence on individual weight loss during one of these weight loss competitions.
The findings are based on the results of the 2009 Shape Up Rhode Island campaign, a 12-week online weight-loss competition. Participants joined with a team and competed against other teams in three divisions: Weight loss, physical activity and pedometer steps.
The weight loss competition included 3,330 overweight or obese individuals (BMI of 31.2 or greater), divided into 987 teams averaging between five and 11 members each.
Weight loss outcomes were clearly determined by which team an individual was on, the researchers said. Participants who lost significant amounts of weight (at least five percent of their initial body weight) tended to be on the same teams, and being on a team with more teammates in the weight loss division was also associated with a greater weight loss.
Individuals who reported higher levels of teammate social influence increased their odds of achieving a significant weight loss by 20 percent. This effect was stronger than any other team characteristic, Leahey said.
“This is the first study to show that in these team-based campaigns, who’s on your team really matters,” she added. “Being surrounded by others with similar health goals all working to achieve the same thing may have really helped people with their weight loss efforts.”
However, individual characteristics were also associated with weight outcomes, she said. Obese individuals had a greater percentage of weight loss than overweight participants. Team captains also lost more weight than team members, possibly due to their increased motivation and engagement in the campaign. Leahey says that future weight loss competitions may consider requiring team members to share the leadership role.
“We’re all influenced by the people around us, so if we can harness this positive peer pressure and these positive social influences, we can create a social environment to help encourage additional weight loss,” she said.
Source: The Miriam Hospital