Connecticut's attorney general has opened an investigation into the calorie-burning claims of a caffeinated drink from the Coca-Cola and Nestle companies.

Called Enviga, the 5-calorie drink has been shown to help people who are already thin increase their energy expenditure according to a study published Monday in the journal of Obesity, USA Today reported.

In the study funded by Nestle, Swiss researchers had 31 lean, young adults drink three cans of Enviga for three days.

On the third day, participants burned on average 106 extra calories or the equivalent of two regular Oreo cookies.

Last week the non-profit Center for Science in the Public Interest filed suit against the manufacturers, accusing them of fraudulent marketing and labeling.

The director of nutrition and health policy for Coca-Cola says Enviga is not being positioned as a weight-loss product.

Copyright 2007 by United Press International