At 6:45 a.m. one Tuesday, Dirk Brotherson had already crossed the Missouri River from Iowa to get to his job in Bellevue, Neb. He stopped at Kabredlo's convenience store, not far from Offutt Air Force Base, to jump-start his day with a Monster wake-up call.

Monster, made by California-based Hansen Natural, combines sugar and caffeine in a bubbly beverage that Brotherson said he relies on to start his day.

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"It kind of just wakes you up in the morning -- peps you up a little bit," Brotherson said. He said he tried SoBe's No Fear and others, but likes the "Kool-Aid and pop" taste of Monster.

Demand Cuts Into Coffee

Monster is among about 500 energy drinks on the market today, and sales of them shot up 49.1 percent in 2006, according to BeverageDaily.com.

Kabredlo's general manager, Brian Mixan, said he's seen demand for the drinks explode in his store, which also offers coffee, cappuccino and regular soft drinks.

"Over the last four or five years, I've noticed just a huge increase (in energy drink sales). It's almost become, I'd say, an addiction. There's a few people that buy in bulk so they don't have that crash later on. It's definitely put a bite in coffee sales," Mixan said.

The Scotter's Coffeehouse across Cornhusker Road from Kabredlo's has taken notice. Director of merchandising Meghan Lewis said she's been adding energy drinks to her stores since last spring, and huge sales have followed. Now, the store is adding energy and wellness drinks with antioxidants and other ingredients that are blended by baristas.

"Health and energy -- that's why people go into coffeehouses," Lewis said. "There's a lot of people that either don't like coffee or want something different. It was something we had to do to keep up in the coffee industry."

Lewis said the energy drinks in her shops are 10 to 15 percent more expensive than the traditional fare. A 20-ounce Diet Coke costs about $1.25, while an 8.3-ounce Red Bull retails at Kabredlo's for $2.69. Amp's 24-ounce can is $2.99.

What Provides The Boost?

Sleepy, listless Americans love all the new options. Doctors and nutritionists hate them.

"It boggles my mind that there are so many silly beverages on the market, but this, too, will pass," said registered dietitian Jeanne Goldberg, a professor at the Center on Nutrition Communication at the Friedman School at Tufts University in Boston. "They promise you can lift the world with one hand and do your day job with the other. People buy into that -- 'I can drink this and feel better.' What these things do is play to the mentality of a quick fix."

The jolt isn't just psychosomatic. Typically, energy drinks have about twice the caffeine of a regular caffeinated soft drink per serving, or about the same amount as a cup of coffee. The energy is delivered from a combination of straight sugar and caffeine, plus a caffeine source called guarana, and sometimes other additives. Many are enhanced with taurine, which is an amino acid thought to enhance caffeine's effect, though study results have been mixed.

None of these compounds are dangerous, per se, nutritionists said, but people who down energy drinks all day long may run into problems. First, the sugar content means most energy drinks are packed with calories. A 16-ounce Rock Star has 280 calories and about 15 teaspoons of sugar. The sugar content is about the same as an equivalent serving of Mountain Dew.

Maxxing Out Caffeine

Caffeine can add up fast, too, registered dietitian Nicole Fox told Omaha television station KETV.

"Take caffeine in moderation," Fox said. "Usually no more than 200 milligrams a day."

By comparison, researchers at the University of Florida College of Medicine in 2003 analyzed 16-ounce servings of caffeinated coffee from specialty shops and found fluctuating readings. On one day, a Starbucks regular measured 259 milligrams and a Dunkin' Donuts regular had 143 milligrams of caffeine, according to a news release from the school.

Pepsi, which began listing caffeine content on all its beverage labels, said Amp has 74 milligrams of caffeine in an 8.4-ounce serving. Kabredlo's sells a 16-ounce and a 24-ounce version of Mountain Dew's Amp, meaning one drink can quickly put you up to the daily max.

Fox said that the more someone uses energy drinks to stay alert, the more he or she will need them to stay alert. Ending use of the drinks can bring on withdrawal-like symptoms, including headaches.

Some drinkers use the products to boost exercise stamina, but dietitians caution that energy drinks' caffeine acts as a diuretic and can cause dehydration, and high levels of consumption can cause heart palpitations.

Mixing It Up

Some people like to mix the drinks with alcohol. Marketers sell the two together with names such as Tilt and Sparks.

"If there's caffeine in it, (it) can make you a wide-awake drunk, and if you don't realize how drunk you are and start driving, that could be a problem," said registered dietician Nancy Clark, author of "Nancy Clark's Sports Nutrition Guidebook" and a director at Sports Nutrition Services in West Newton, Mass.

Clark said she's less worried about the calorie content in an energy drink than the fact that people are choosing it as a quick-fix over something with equivalent calories that is more wholesome.

"(You'd get energy) if you ate 100 calories of a banana. The better solution is to remember that food is fuel. You have a car, you put gas in it, it goes. When your car runs out of gas, you find time to go to the gas station. Some people are nicer to their cars than they are to their bodies," she said. Other Links:

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