Motivation to drop a few pounds can come from unexpected places.

Brigitte Zeitlin, M.P.H., R.D., owner of BZ Nutrition, took a look at two popular strategies and breaks them down for us.

THE MOTIVATION: BETTER PERFORMANCE AT WORK

Study says: People who took part in a weight-loss program were able to work more hours than they could previously—likely because their weight loss improved their health, so they didn't take as many sick days.

Will it work for me? It has promise. "When you're healthier, you can handle stress better and your confidence is boosted, which can help at the office."

THE MOTIVATION: COLD HARD CASH

Study says: Out of two study groups that hit their weight-loss goals, the group that was eligible for extra cash rewards lost twice as much weight in eight months.

Will it work for me?"Once the money stops, you'd need a new motivation." One option: Many employers offer wellness programs that give workers breaks on insurance premiums for participating.