You could visualize yourself fitting into a dress two sizes smaller, but one of the best get-slim motivators may be cold, hard cash, according to a study in the Journal of Occupational and Environmental Medicine. Employees who were promised $14 for every 1 percent drop in body weight shed about a third more pounds than those who received just $7 and more than double those not given any cash.

"You can duplicate this success by creating your own financial reward system," says Eric Finkelstein, lead researcher and author of The Fattening of America. Start a weight-loss pool at work or among your friends; the biggest loser after a set period takes the largest percentage of the pot, while those who drop fewer pounds collect less.