A new study shows that people who shed at least 5% of their initial body weight during a weight loss competition were likely to be on the same teams. Those who said their teammates played a large role in their weight loss were more likely to lose a significant amount of weight.

The findings appear in Obesity.

Shows like The Biggest Loser often have team-, family-, or couples-based competitions that harness the power of peer influence when it comes to weight loss.

"People around us affect our health behaviors," says researcher Tricia Leahey, PhD. She is with The Miriam Hospital's Weight Control and Diabetes Research Center and is an assistant professor of psychiatry and human behavior at Alpert Medical School of Brown University in Providence, R.I.

This is true for healthy and unhealthy behaviors. "It could be quite beneficial if a bunch of friends that choose to lose weight make healthy food choices together, and hold each other accountable to those choices," she says.

Team members can motivate one another to stay the course. "If someone is doing really well, it could influence the whole group," Leahey says.

The findings are based on the results of the 2009 Shape Up Rhode Island campaign, a 12-week statewide, online weight loss competition. Participants competed against other teams for weight loss, physical activity, and the number of steps taken. The weight loss arm included 3,330 overweight or obese people on 987 teams. The teams had between five and 11 members.