Some members of the medical community worry that the high amount of caffeine in Enviga -- 100 milligrams per serving, or 300 if drinkers consume the suggested three cans per day -- could increase metabolisms to dangerous levels.
"The caffeine intake [of] 300 milligrams per day is a level that can cause jitteriness...elevated heart rate, and anxiety," said Leslie Bonci, director of sports nutrition at the University of Pittsburgh Medical Center.
Bonci said that despite its shiny silver packaging, Enviga is no magic bullet.
"Everyone wants the magic bullet for weight loss, so this will be one of many products people will try in the quest for the quick fix," she said. "The issues are not just weight loss, but safe weight loss. Caffeine is not safe for everyone especially in larger quantities."
Doctors fear that Enviga encourages Americans to search for a quick fix for weight loss and ignore the time-honored solution -- eating right and sweating off the pounds with exercise.
"My concern is that when people latch onto this, they think they don't have to do the hard stuff," Katz said. "The fundamentals of healthful eating and activity do pertain to everybody."
Not only could Enviga lead dieters down the wrong path, the three-cans-per-day recommendation could also pan out to be an expensive weight loss venture.
"Given the fact that a pound is 3500 calories...at $1.30-$1.50 a can it is going to cost anywhere between $136-$315 to lose a pound," Bonci said. "You can put on a pair of walking shoes and burn more calories without paying a dime."
Rather than drinking Enviga, doctors might offer the following prescription for dieters: get off the couch, exercise, drink regular green tea afterwards -- science shows the beverage in its pure form is indeed healthful. Repeat and reap rewards in the New Year.