Green Tea + Caffeine =
Negative Calories?
(New Energy Drinks)
by Shari Roan

Experts disagree on whether new energy drinks can boost metabolism.

Beverage makers have created a new class of soft drinks they say use a combination of green tea and caffeine to help consumers boost their metabolic rate to burn more calories than the beverages contain.

The brands include Enviga, Arizona, Celsius and Snapple.

The shoppers looked skeptical.

"This is the first drink that can actually help you lose weight," sales representative Anthony Monforte said confidently, handing out tiny samples of a new soft drink, Celsius, at a Vitamin Shoppe in Aliso Viejo, Calif.

Leslie Bedford and Marsha McDonogh, office workers who had stopped by on their lunch break, took cautious sips. "Hmmm. It does taste like RC Cola," McDonogh said, agreeing with Monforte's description. Sold on the taste - and especially the promise - she plunked down $6.99 for a four-pack.

"If it really works, that's great," Bedford said. "Everyone in our office wants to lose weight one way or another."

Beverage makers are counting on it. Stung by falling sales and criticism that sugar-sweetened soft drinks raise the risk of obesity, they're reaching into scientists' laboratories to come up with healthier products - vitamin waters, sports drinks, fortified juices and now so-called negative-calorie drinks.

The drinks, most notably Celsius and Coca-Cola's and Nestle's Enviga, promise to boost metabolism and burn calories.

The key ingredients are green tea and caffeine.

Celsius' manufacturer says its particular combination will increase metabolism enough to burn up to 77 calories per 12-ounce bottle; Coke states that three 12-ounce cans of Enviga will burn 60 to 100 calories. Snapple has also introduced green tea beverages, with labels that claim they boost metabolism.

"Consumers are looking for some functional benefit," says John Sicher, editor and publisher of Beverage Digest, an industry trade publication. "They are saying they want their calories to do something for them."

The effects of the green tea drinks go beyond those of caffeine-laden zero-calorie sodas, the manufacturers of Celsius and Enviga say. An antioxidant found in green tea - epigallo catechin gallate, or EGCG - significantly increases metabolism, they say. This, in turn, boosts the body's ability to burn fat.

Raising metabolism is more complicated than simply ingesting a chemical that speeds up the heart rate, which often makes users jittery.

Although scientists still aren't sure just how EGCG works, some suggest it triggers greater production of a neurotransmitter called norepinephrine, elevating metabolism. Caffeine also raises the metabolic rate, and early research suggests combining EGCG with caffeine is the key to a measurable increase.

The concept is intriguing - but far from proven, pharmacology experts point out.

"The data are still emerging," says Roger Clemens, a spokesman for the Institute of Food Technologists and an adjunct professor of pharmacy at the University of Southern California. "They are not convincing."

Jeffrey Blumberg, a senior scientist in pharmacology at Tufts University is similarly skeptical.

"In really carefully controlled studies, you can actually find an increase in metabolic rate," he says. "But if the effects are modest, it might be hard to see them in the real world."

Other studies have shown that the antioxidant does have potential to help prevent some types of cancer, they acknowledge, but the effects on metabolism shouldn't be counted on at this point.

The makers of Enviga and Celsius say they have research to support their weight-loss claims.

In a study of Celsius, which contains five to 10 calories a bottle depending on the flavor, 20 people were divided into two groups, with one group consuming 12 ounces of Celsius and the other group consuming 12 ounces of Diet Coke.

The volunteers' metabolic rates were measured before and after consumption. The study showed an average increase of 12 percent in metabolic rate over a three-hour period among those drinking Celsius compared with a 4 percent to 6 percent rise in the Diet Coke drinkers.

Depending on the person's own metabolism (which varies by fitness level, weight, gender and age among other factors), a 12 percent increase could result in burning up to 77 calories a bottle, says Elite FX, the manufacturer of Celsius, which funded the study. The research was conducted at Ohio Research Group of Exercise Science and Sports Nutrition and was presented last year at a meeting of the International Society of Sports Nutrition.

A study of Enviga, which contains five calories per can, showed that drinking three 12-ounce cans a day increased calories burned by 60 to 100 per day. The study, performed at the University of Lausanne in Switzerland, has not been published.

"The data show the green tea extract appears to enable this gentle boost in the metabolic rate," says Rhona Applebaum, chief scientist of Coca-Cola. "The second mechanism is caffeine. The two together - what we have found and what other studies have found - produces this synergy that allows for this gentle boost in rate."

Enviga was launched in October in the northeast United States and will become available nationwide in January. Sweetened with aspartame, it comes in three flavors - green tea, berry and peach - and sells for about $1.29 to $1.49 a can.

Celsius, which sells for roughly $1.99 a bottle, was launched in June 2005. Sweetened with sucralose, or Splenda, it, too, is available in a variety of flavors.

Caffeine, of course, plays a role in the drinks' effect on metabolism. Celsius contains 200 milligrams of caffeine and Enviga 100. A Coke or Pepsi contain approximately 35 milligrams of caffeine; a 5-ounce cup of coffee has about 100 milligrams. Celsius also contains seeds of guarana, an Amazonian berry, which contain caffeine.

But EGCG's effect on metabolism is stronger than that of caffeine, the drink companies say.

"We tested the whole bottle," says Janice Haley, owner and vice president of Elite FX. "We know it's all the ingredients working together that causes the increase in metabolism."

The same EGCG-and-caffeine combination can presumably raise metabolism and burn calories among drinkers of hot green tea.

Numerous laboratory and animal research, plus a few studies in humans, have measured an increase in metabolism from green tea consumption. And many dietary supplements containing green tea extract also make weight-loss claims.

But the green tea carbonated soft drinks are aimed at specific markets: gymgoers watching their weight, and consumers who normally down several 150-calorie sugary sodas a day but are thinking of switching to something healthier.

Of course, simply exercising and replacing regular sodas with low- or no-calorie drinks could obviously help Americans shed excess pounds.

Shoppers appear to be tuning in to the chorus of health professionals who say soft drinks are playing a sizable role in rising rates of obesity. Sales of carbonated soft drinks fell last year - by 0.7 percent - for the first time in two decades.

A study presented last year at the Experimental Biology annual meeting found that sugary soft drinks are the leading source of calories in the average American diet, accounting for as much as 9 percent of energy consumed. A little more than a decade ago, white bread was the biggest source of calories.

The study also found that obesity rates were highest among regular soft-drink consumers.

A review of 30 studies published in August in the American Journal of Clinical Nutrition found that greater intake of sugar-sweetened beverages was linked with weight gain and obesity in children and adults.

Today, sweetened soft drinks are targeted for removal from campuses by school boards and are vilified by most health professionals.

A few health organizations have even proposed adding a federal tax to soft drinks to try and curb consumption.

"We're at a turning point," USC's Clemens says. "Consumers are really being encouraged to make more healthful choices."

These new drinks fit that bill - for some people.

Although Celsius' maker has backed away from earlier statements that drinking it regularly over the course of a year could lead to a 17-pound weight loss, the company markets Celsius as a "replacement" for high-calorie, sweetened soft drinks.

"We are careful not to say that this is a weight-loss product," Haley says.

Coke views Enviga as "another step" for consumers who are trying to become healthier, Coca-Cola's Applebaum says.

Shari Roan, Los Angeles Times, Published The Ledger,
http://www.theledger.com/, December 26, 2006