People in the second group lost almost three times as much weight than those in the first, according to the study.
"We've found a lot of success among teams where you already know your teammates," Roddenberry says. "People are more motivated by not letting their team down than they are by doing it for themselves."
The company has also identified other key factors that lead to effective weight loss.
"A really big headline number is important," Roddenberry says. "100 bucks, 200, 400, is not going to move the needle with behavior change. But if you say you can win $10,000 ..."
Also important is having a stake in the competition. People who make an investment -- such as paying $150 up front -- are more motivated by losing that money than by doubling it, Roddenberry says.
Of course, not everyone has a competitive personality.
Men tend to do better on HealthyWage than women, he notes, and the website attracts more users who are "money motivated" -- coupon clippers or discount shoppers who value the return on their investment.
"It's so personal," Roddenberry says of weight loss. "Different people have different motivations."
Right now HealthyWage is "one size fits all," he says. But in the future, the company hopes to provide customized programs that will fit each person's needs, whether that's a bigger prize, a shorter time period or weekly incentives.
It's tough, Teuscher says, to stay on track without the proper motivation. "Once you get to where you are you miss what you had before. Food is a big temptation."
He's joined the BMI Challenge in hopes of getting down to 180 pounds and doubling his initial investment.
Whicker joined another Matchup team challenge with his wife, Alisa, after the first; they took fourth place. Now he's participating in the 10 percent Challenge to lose 10 percent of his body weight in six months.
He doesn't track calories, focusing instead on eating five to six small healthy meals a day. He hits the gym for an hour to two hours most days and takes his kids, Riley, 6, and Samantha, 2, out to ride bikes or swim at the pool.
Since June 2012, when he first joined HealthyWage, he's lost 128 pounds.
"I'm still getting there," he says. "Part of it is time; part of it is understanding what really matters in life. ... As you start to have kids, suddenly you come to the realization that there (are) more people depending on you than yourself."