The Coca-Cola Co. and Nestlé have been reportedly hit by yet more controversy about their 'calorie-burning' joint venture.

The two companies, who together run Beverage Partners Worldwide (BPW), are under investigation by Connecticut's attorney general, according to today's (6 February) Wall Street Journal.

The investigation centres on claims that drinking three 12-oz cans of BPW's Enviga drink over a 24-hour period can prompt a healthy person of normal weight to burn about 60 to 100 calories more than they normally would.

"Anybody claiming that a product burns calories is [by implication] talking about weight loss or control," the state's attorney general, Richard Blumenthal, is cited as saying in the report.

"We want credible scientific evidence that it causes calorie-burning in a representative sample of the general population over a sustained period of time."

Speaking to just-drinks today, however, a spokesperson for Coca-Cola North America said: "Beverage Partners Worldwide stands behind the science that supports our claim that Enviga invigorates your metabolism to gently burn calories.

"We have been clear that Enviga is not positioned as a weight loss product, but is designed to complement, not replace, regular exercise, a sensible diet and other healthy choices you make throughout the day."

US consumer watchdog the Center for Science in the Public Interest yesterday filed a lawsuit against the two companies, alleging that they are making "fraudulent claims" regarding the "negative calorie" effect of Enviga.