Retired U.S. Army Sergeant Major Rick Cayton says he isn't interested in most energy bars available at his local grocery store in Killeen, a small town near the Fort Hood military base in central Texas. But the decorated Vietnam War veteran says he loves the Hooah! bar, the official nutrition bar of the U.S. military.

"The Hooah! bar is good tasting and it gives you energy over a period of time, not just a spike," says Mr. Cayton, 54 years old, who discovered the energy bars while visiting the troops in Iraq last fall. "I'd love to take them with me on fishing trips."

The fast-growing energy-bar industry has thrived on the impulse purchases of overworked yuppies, chiseled athletes and diet-conscious soccer moms. But the Hooah! bar's military origin has created a new niche of nontraditional energy-bar consumers who, like Mr. Cayton, are clamoring for the $1.99 snack sold at supermarkets, hunting and fishing emporiums and convenience stores.

Five years ago, the Department of Defense Combat Feeding Directorate in Natick, Mass., developed the bar to give soldiers an extra boost. Unlike commercial bars, the Hooah! met the Department of Defense's strict performance-based combat requirement that "meals ready to eat" have a minimum shelf life of three years at 80 degrees Fahrenheit and six months at 100 degrees. The product's name (pronounced WHO-ah) evolved from "H.U.A.," the abbreviated reference for the affirmative response "Heard, Understood and Acknowledged."

Ray Scott holds an oversized Hooah! bar with U.S. troops in Iraq.

The Hooah! bars, which took nearly three years to develop, became available to civilian consumers in select stores last August and will expand to nearly 12,000 retailers this spring. The launch corresponds with an increase in patriotism in recent years and general support for the U.S. military, a sentiment that has transferred to the marketplace.

"No matter what people think of the war in Iraq, everyone supports the troops," says Christian D'Andrea, who discovered the bars two years ago when he was filming a documentary about the military. Last winter, Mr. D'Andrea, 33 years old, and his brothers Mark, 30, and Paul, 35, gained exclusive rights to license and distribute the bars to civilian consumers.

Under the agreement, the Los Angeles-based D'Andrea Brothers LLC manufacture, distribute and market the bars to the private sector and in turn, give a portion of all proceeds back to the military's research and development department.

Christian and Mark D'Andrea, Harvard graduates and Eagle Scouts with no background in sales or marketing, saw built-in potential in the bar's military association. Each bar's silver package reads "The performance nutrition bar created by the U.S. military" and features a "support the troops" ribbon. Advertisements for the bars, which come in chocolate and apple cinnamon flavors, have appeared in hunting and fishing magazines, and the D'Andreas plan to launch a version with a camouflaged wrapper.

Bonnie Liebman, director of nutrition for the Washington-based consumer-advocacy group Center for Science in the Public Interest, says the Hooah! bar's main contents -- corn syrup, soy protein isolate, fructose and maltodextrin (an easily digestible carbohydrate made from corn starch) -- are found in most nutrition bars. "The military association is a good marketing ploy," she says.

In 2004, so-called wellness bars -- including breakfast, cereal, granola, nutritional and energy bars -- were the fastest-growing food category in the U.S., with an estimated yearly growth rate of 20% and annual sales of $1.9 billion per year, according to the Grocery Manufacturers Association, a trade group that represents several energy bar manufacturers, among other categories. PowerBar, credited for kicking off the bar trend when it hit the market in 1986, is now owned by Nestlé SA and has been endorsed by cyclist Lance Armstrong.  Kraft Foods Inc. owns the Balance Bar and Rexall Sundown Inc., a Bohemia, N.Y., health-product manufacturer, owns the high-calorie Met-Rx bar.

Supermarket checkout stands and convenience stores are flooded with niche bars like Luna (owned by the Berkeley-based Clif Bar Inc.) for women, Protein Revolution for endurance athletes and the Think bar, which promises to sharpen brainpower.

But the enterprising D'Andrea brothers are betting that the military link will give their bar an edge in the so-called red states, where they say the majority of America's 40 million hunters and fishermen go on an average of 60 outings per year and spend over $6 billion per year on food for these trips. "These people are pro-soldier. They trust what comes from the military, and they represent huge potential for energy-bar growth," says Mark D'Andrea.

Military support has helped other foods get off the ground. According to the Department of Defense, about 30% of all supermarket foods, including freeze-dried coffee, Mars Inc.'s M&M's and some dried cake mixes, were originally developed by the U.S. government for military consumption. "You take a lot of stuff for granted when you walk around the supermarket," says Gerald Darsch, director of the Combat Feeding Directorate at the Natick Soldier Center and one of the Hooah! bar's developers.

Ray Scott, founder of the Bass Anglers Sportsman Society, says before he discovered the Hooah! bar he didn't eat energy bars. Now, he buys apple-cinnamon Hooah! bars in bulk. He even gave a box to his fishing buddy, President George W. Bush on a recent visit to the White House. "These things are as American as apple pie," says Mr. Scott, 71 years old.

While the D'Andrea brothers' marketing conceit appeals to some segments, it has alienated others. At a recent promotional event at a Gold's Gym in Los Angeles, several passersby snubbed the bars in protest of the war in Iraq.

That doesn't bother the D'Andrea brothers. They calculate that the bar can thrive even if it only appeals to conservative-leaning consumers.