"Don't drink your calories" is a good advice if you're trying to watch your weight, even if it's fruit juice you're drinking.

Researchers gave 34 young men and women -- half were overweight or obese and half were lean -- rougly 400 to 550 calories a day of either solid food (fruits and vegetables) or fruit juieces. (Each participant gotenough food or juice to comprise 20 percent of his or her usual calorie intake.) This solid food, which came to six to eight servings a day, was 10 percent vegetables (raw carrots, broccoli, adn cauliflower), 35 percent fresh fruit, and 55 percent dried fruit.

After 8 weeks on the fruits and vegetables, the people in the lean group compensated for the extra food by cutting back on their usual diets. They gained no weight. However, they gained about 3/5 pounds after eight weeks on the juice.

The overweight and obese partipcants fared well. They gained four pounds after eight weeks on the fruits and vegetables and five pounds after 8 weeks on the juice. 

What to do: Eat fruits and vegetables instead of drinking juice. And don't assume that you can't gain weight by loading up on veggies and fruit (especially dried fruit, which is calorie dense). Eat fresh fruits and vegetables instead of -- not in addition to -- higher-calorie foods.