Have you heard how many fruits and vegetables you're supposed to be eating each day? Try not to choke. The USDA's newly published guidelines at mypyramid.gov say an active man in his 30s or 40s needs upwards of six cups a day. That's right: six. That's two small oranges at breakfast, two at lunch, two at dinner, and three more vegetable- or fruit-based snacks in between. (One cup is one to two pieces of fruit or three short stalks of broccoli.)

Right now only 4 percent of American men (ultramarathoners and hardcore vegans, presumably) actually eat this much produce. Which is not to say you shouldn't try. According to the National Cancer Institute, every additional daily serving of fruit or vegetables reduces your risk of heart disease by 4 percent. A Harvard study that followed 110,000 men for 14 years found that those who ate eight or more servings of fruits and vegetables each day were 30 percent less likely to suffer a heart attack or stroke than those eating only one. And a 2005 World Health Organization survey found that fruit and vegetable intake is one of the industrialized world's top ways of lowering the risk of cancer.

If you can't manage to jam that much roughage into your face on a daily basis, however, juice may be the answer. The beverage industry certainly thinks so. It's turning its attention to "super-premium juice," a category that's projected to be a $1.4 billion industry two years from now, with sales up 43.5 percent already this year. Jamba Juice franchises, which emphasize the healthful benefits of their juice products, are spreading like Starbucks (and command similar customer loyalties). Business is so good for Naked Juice that this year it expanded production with a line of caffeinated juices. And big juice manufacturers are now in the game: This summer Tropicana released its Pure line, which eschews added sugar and incorporates antioxidant-rich fruits like blueberries and pomegranate.

Still, many in the medical establishment maintain that even the purest juice is no substitute for fresh fruit or vegetables. Compare an apple and a glass of apple juice. A medium-size apple contains 80 calories, 21 grams of carbohydrates, and 3.7 grams of fiber; an eight-ounce glass of apple juice contains nearly 50 percent more calories and carbs, and virtually no fiber. "My main concern about juice is that I know we're not getting enough fiber in this country," says Cindy Moore, director of nutrition therapy at the Cleveland Clinic.

Juice proponents like Paul Sale, a top New York City chef, concede that fresh fruit contains more fiber than juice does, but he argues that proper juicing preserves more fiber than one would think, and, more important, that it breaks down a plant's cell walls to allow antioxidants to be more easily digested. Juice advocates also contend that juicing concentrates nutrients. It takes a bag of carrots to make eight ounces of juice, after all, so it follows that a glass of juice contains more vitamins than a single serving of whole carrots. Some argue that juice has its own redeeming qualities. On the alt-remedy fringes of the juice advocate ranks you'll find unabashed claims for the curative powers of juice. Beet juice, for instance, is said to alleviate eye fatigue and skin problems.

But don't let arguments between dietitians and the raw-food faithful distract you from what's important. While it's useful from an academic standpoint to compare fresh apples and apple juice, nutritional decisions rarely work like that. As you grab lunch, you don't ask yourself whether you want an apple or apple juice. You ask yourself whether you want a glass of juice or a Coke.