If you're juicing to slim down-a trend that is now back in vogue-lacking scientific evidence suggests that you should think twice. (Find out how many calories you should be eating daily.)

It is true that if your juicy diet delivers fewer calories than you need, you'll lose weight, but you may not sustain it. Losing weight isn't necessarily about depriving yourself of everything you love-it's about eating fewer calories than you're burning.

Here's another reason to think twice about juicing to lose weight: research shows that drinking your calories leaves you feeling less satisfied than if you were to eat those calories.

A little juice can be good for you though. Drinking 100 percent fruit or vegetable juice can help boost your produce intake-a good thing considering most Americans fall short in meeting the recommended intake (5 1/2 cups daily for a 2,000-calorie diet). That said, don't go overboard and drink a refrigerator drawer worth of produce in one sitting. We drink more than half of our fruit intake. And juice has less fiber and is more calorie-dense than whole produce: two medium oranges deliver about the same number of calories as a cup of orange juice, but boast 12 times the fiber. Whole, unprocessed fruits and vegetables are also healthier because they generally have more phytochemicals (the compounds behind the disease-fighting benefits of produce).

Bottom Line: When it comes to getting your daily fruit and veggie fix most of your servings should come from whole or cut-up fruits and vegetables. When choosing juice, look for one that's 100% juice-and is pasteurized. Making your own? Only prepare what you'll drink right away, as harmful bacteria can grow in juice quickly.