On your next shopping trip, load up on fruits and veggies and skip the candy and cookie aisles; then try eating from dessert rather than dinner plates. Those two small steps added up to a huge but painless calorie reduction in a Pennsylvania State University study of 24 women.

For 4 weeks, the women ate similar foods one day a week. Then, on the following day, the researchers cut about 544 calories by replacing fat and sugar with fruits and vegetables; they also trimmed 256 calories by cutting portion sizes by one-quarter.

Amazingly, the women didn't increase the amount of food they ate to compensate on day 2, although they were allowed to eat as much as they chose.

The magic: Produce fills you up with calorie-free fiber and water, and small reductions in portion size don't register as deprivation.