NEW YORK (Reuters) Weight Watchers International Inc sued Jenny Craig Inc for allegedly lying in advertising about a supposedly superior weight-loss program to capitalize on consumers New Year s resolutions to shed extra pounds.

According to the lawsuit filed on Tuesday in Manhattan federal court, Jenny Craig falsely claimed in a television commercial that a major clinical trial shows its clients on average lost more than twice as much weight as those on the largest weight loss program, a reference to Weight Watchers.

The commercial features the actress Valerie Bertinelli, clad in a lab coat and surrounded by scientists and is part of a TV, print and Internet campaign designed to capitalize on this crucial consumer dieting season, the lawsuit said.

Weight Watchers said Jenny Craig did not in fact conduct a major clinical trial comparing the companies products and alleged that studies Jenny Craig cited were conducted 10 years apart and not useful in such a comparison.

The campaign is clearly unsupported by fact or science, Weight Watchers Chief Executive David Kirchhoff said in a statement.

Jenny Craig, a unit of Switzerland s Nestle AG, had no immediate comment on the lawsuit.

New York-based Weight Watchers is seeking to halt the ad campaign and to force Jenny Craig to run corrective advertising, give up improper profits and pay punitive damages, among other remedies.

Last September, Weight Watchers accused Nestle in a separate lawsuit of displaying trademarks for Weight Watchers and its Points weight loss system without permission. It said the displays were on packaging for its Stouffer s Lean Cuisine and Skinny Cow diet ice cream products.

In afternoon trading, Weight Watchers shares were down 7 cents at 29.05 on the New York Stock Exchange.

The case is Weight Watchers International Inc. v. Jenny Craig Inc, U.S. District Court, Southern District of New York, No. 10-00392.

(Reporting by Shobhana Chadha in Bangalore and Jonathan Stempel in New York; editing by Anil D Silva and Andre Grenon)