The nonprofit Center for Science in the Public Interest  (CSPI), Washington, D.C., has filed suit  against Coca-Cola and Nestlé for making fraudulent claims in marketing and labeling for Enviga, a new artificially sweetened green tea soft drink. Labeled “the calorie burner” on cans, Enviga is marketed as a weight loss aid, with claims that it has “negative calories” and that it can “keep those extra calories from building up.” Enviga’s website also says the drink is “much smarter than following fads, quick fixes, and crash diets.” But according to CSPI scientists who reviewed the studies cited by Coke and Nestlé, Enviga is just a highly caffeinated and over-priced diet soda, and is exactly the kind of phony diet aid it claims not to be.

The suit was filed in U.S. District Court in New Jersey, part of the region in which the beverage is being introduced. In December, CSPI served formal notification on Coke and Nestlé (and their partnership, Beverage Partners Worldwide) that they would be sued if they continued to use the unsubstantiated calorie-burning and weight-loss claims on Enviga labels and ads, but the company indicated publicly and privately that it had no plans to change the claims.

Enviga consists of carbonated water, calcium, concentrated green tea extract, various “natural flavors,” and ingredients typically found in diet soda, such as caffeine (three diet colas’ worth), phosphoric acid, and the artificial sweeteners aspartame and acesulfame potassium. The company says its green tea extracts are high in an antioxidant called epigallocatechin gallate, or EGCG.

Many of Enviga’s claims are based on a 72-hour Nestlé-funded study of 31 people who were given a drink containing amounts of EGCG and caffeine equivalent to three cans of Enviga. On average, those subjects expended more energy, according to an abstract of the unpublished study. In any event, none of the 31 were overweight or obese—in fact all were quite lean to begin with. In other words, the company’s test may have detected some slight evidence that it increases calorie burning slightly—but only in a short-term test of thin people who were given a strictly controlled diet. And when the study was presented at a conference of the Obesity Society, the society disputed the study’s conclusions, insisting “it is improper to state or imply that the results of this study supports any weight loss” claim.

Enviga costs between $1.29 and $1.49 per can, and the company suggests that the maximum effect is gained by drinking three cans a day, or about $1,500 worth of the soda per year.

“There is no clear evidence that what’s in Enviga will help you control your weight,” said CSPI senior nutritionist David Schardt. “You’d be much better off giving up non-diet soda, which costs nothing to do, or by joining a gym, which is typically less expensive than paying for 3 cans of Enviga a day.”

CSPI will be represented by its litigation director Stephen Gardner, and by Mark Cuker and Michael Quirk from the firm of Williams Cuker Berezofsky, based in Cherry Hill, NJ.