They provide the promise of a quick portable meal, an afternoon energy boost or a way to eat healthfully while traveling.

Born in the world of competitive athletics, nutrition/energy bars have moved into the mainstream: These days they're often gobbled by sedentary desk jockeys rather than solely by the mountain climbers and elite athletes who first made them popular. Sales of the bars are projected to reach more than $3 billion in the United States this year, according to the Nutrition Business Journal, a California publication that tracks the food industry. Companies from Atkins to the Zone have gotten into the act.

So what exactly do these bars provide nutritionally?

"There's nothing magic in them," said registered dietitian Nancy Clark, author of the "Sports Nutrition Guidebook" (Human Kinetics). "Even though they're marketed to be easily digestible or an energizer, another snack would do that. Many people think that anything wrapped in a package is magic in terms of enhancing performance, but they're just 200 expensive calories."

One appeal of energy bars, of course, is convenience. They don't require refrigeration and are unlikely to spoil or crumble for months, making them ideal for tucking in a purse, briefcase, backpack or gym bag.

Just don't expect them to offer a nutritional advantage. Energy bars often boast of their high protein, but they often also pack added sugars and saturated or trans fat. The Clif Bars that Clark keeps in her desk have 12 grams of protein, 40 grams of carbohydrates and 250 calories "They're absolutely delicious," she said, munching on one during a recent interview. "They have chocolate and frosting and fudge and Rice Krispies. But who am I fooling? This is sugar-coated protein with vitamins added to it."

Compare that to a glass of skim milk and a medium banana (10 grams of protein, 40 grams of carbs, 185 calories) which has about the same nutritional value as that Clif bar.

Most bars, at $1 to $3 each, will cost as least twice as much as the banana and milk. And while energy bars are increasingly billed as meal substitutes, "they're not really big enough for a meal replacement," Clark said. "You'd need to eat two to three of them" to feel full.

Except that you might not want to, based on a recent and decidedly unscientific Lean Plate Club taste test of a dozen leading energy bars. Even the best-rated bars, including one from a major candy maker, averaged only modest scores for taste. Many fared much worse. [See results in the chart below.]

Asked whether they would purchase any of the bars as a snack or meal replacement, most participants said not a chance -- unless, of course, they were starving.

To conduct this blind taste test, we purchased 11 leading energy bars (based on national sales) from local stores. Added to the mix was a ringer, the Snickers Marathon Chewy Chocolate Peanut bar made by Mars Inc.

The taste test was conducted late on a Friday afternoon, a time when deadline pressure and hunger rises. Participants -- all Washington Post newsroom personnel -- were invited to sample as many of the bite-size samples as they desired. After each bite, they were asked to rate the taste on a scale of 1 (terrible) to 10 (great). Scores were then tallied and divided by the number of people who tasted each bar to arrive at an average score.

Not one bar earned a 10 from even a single taster, although a few bars -- including the ZonePerfect Fudge Graham bar, Luna Nutz Over Chocolate bar, Snickers Marathon, EAS Advantage Edge Chocolate Peanut Crisp and SlimFast Caramel Crispy Peanut Meal Bar -- snagged an occasional 9. The Myoplex Lite Blueberry Cobbler Crunch Nutrition Bar got a minus-1 from one tester.

The top average score was a 6 for the Zone Perfect Fudge Graham bar. Least favorite: Atkins Advantage Chocolate Mocha Crunch Bar, which averaged 2.4.

Here are some for tips in choosing energy bars:

Let taste be your guide. Nearly every bar appealed to at least one taster, yet even the highest-scoring bars had detractors who couldn't stomach them. If you want to use these bars, you may have to taste a bunch to find one you like -- or can tolerate.

Read the labels carefully. The Atkins Advantage bar had 10 grams of fat -- the highest in the test, including six grams of saturated fat. That's two grams more than a small McDonald's burger and bun. Lowest in fat: PowerBar (the leading U.S. seller) and Myoplex Lite. Each had 3.5 grams of fat and was low in saturated fat -- less than a gram for the PowerBar, 2.5 grams for Myoplex. The SlimFast Chocolate Brownie Bar and the Clif Bar Crunchy Peanut Butter were the only two brands to note on their labels that they had zero trans fat.

Look for bargains. Sales and frequent-buyer cards, such as those offered at CVS, dropped the cost of some bars to less than $1. Costco, Sam's Club and Trader Joe's also often offer lower prices for bulk sales of energy bars.

Make it your whey. Energy bars often have more protein than traditional candy or snack bars, which is why they have been favored by athletes. Their protein generally comes from whey (a milk protein), soybeans, nuts or a combination of all three. Highest protein of any bar tested: Atkins Advantage, with 20 grams. Both Zone Perfect and SlimFast's Chocolate Brownie had 16 grams. Oneway, which also bills itself as a protein supplement, had 15 grams. By comparison, the top-selling energy bar, PowerBar, had 10 grams of protein.

Dig deep. Be aware that there are different types of products in the category, each aimed at a different niche and (perhaps) delivering a different balance of nutrients. Clif Bars contain certified organic ingredients. Luna bars derive their protein from soy and are aimed at women (though plenty of men eat them, too). Myoplex, EAS Advantage, Balance, PowerBar and Snickers Marathon mostly target energy and athletic performance. Balance, for example, provides 100 percent of the daily vitamin C intake, which could help make up for not eating enough fruits and vegetables. PowerBar contains 30 percent of the day's calcium and 100 percent of the essential B vitamins, and it provides 300 micrograms of sodium, potassium and chloride, electrolytes that are lost in perspiration during a workout. SlimFast, the Zone and Atkins are geared toward meal replacement. All bars come in single servings, making portion control easy. Products are constantly changing. Since our testing two weeks ago, SlimFast has introduced a new bar with less sugar.

Consider other healthy snacks instead. Low-fat chocolate milk "is as effective as a recovery food" as energy bars after a workout, Clark said.

A recent study -- conducted by Indiana University researchers and presented at the American College of Sports Medicine's annual meeting -- tested raisins against energy gels, which are nutritionally similar to energy bars. Bicyclists who ate raisins before their workouts performed just as well as those who ate energy gels. The raisins "were just as effective, no one complained about intestinal problems and they cost just a fraction of the price of the energy gels," Clark said.

Share Your Tips or ask questions about healthy nutrition and activity when Sally Squires hosts the Lean Plate Club online chat, from 1 p.m. to 2 p.m. today, on www.washingtonpost.com. Can't join live? E-mail leanplateclub@washpost.com anytime.

New To The Club? The Lean Plate Club is devoted to healthy eating and boosting activity. To learn more, and subscribe to our free e-newsletter, visit www.washingtonpost.com/leanplateclub.