PORTLAND, Maine -- Here's something that sounds almost too good to be true: A soft drink that can actually help a person lose weight.

The drink, called Celsius, is manufactured by a Florida company and is now hitting shelves in Maine, Portland television station WMTW reported.

Its makers claim that Celsius is the first "clinically-proven, calorie-burning" soda, asserting that each bottle will burn up to 77 calories over a three- to four-hour period.

The secret, said Janice Haley of Elite FX, is in the natural ingredients, which include green tea, ginger and B vitamins.

Haley explained, "The way Celsius works, it raises your metabolism by 12 percent."

The station held a taste test, and while most first-time Celsius samplers raved about the taste, many found the claims that a soda can burn calories a little hard to swallow.

Exercise physiologist Dawn Strout said she is skeptical. While she said she doesn't discredit the claims, she said she doesn't believe there is any quick fix to weight loss. She said she believes in raising metabolism naturally.

Strout said, "If you increase the amount of muscle you have through resistance training, that's going to be something that's going to be longstanding. Where as far as a drink -- we don't know how long that's going to be longstanding in the body."

With five to 10 calories per bottle and no sugar, its makers tout Celsius as a healthier alternative to regular sodas.

But each bottle is loaded with 200 milligrams of caffeine, the equivalent of two cups of coffee. The manufacturer recommended children under 12 and women who are pregnant or nursing not drink Celsius.

They also said that no one should drink more than three bottles a day.