They beckon from supermarket-check-out racks with alluring packaging and absurdly tasty-sounding flavors: chocolate banana split, java chip, mocha latte swirl. But unlike candy and cookies, energy bars have staked out the nutritional high ground. They promise guilt-free bursts of energy and obscure but seemingly healthful extras--antioxidants, "fast-burn nutrition technology" and, in the breathless words of one, "31,000 mg amino acids!"
No wonder Americans are eating them up. Energy-bar sales are expected to hit $500 million in 1998, up 40% in a year. And they have moved from the retail fringe--health-food stores and bike shops--to become a grocery- and convenience-store staple. When...