Analysts say they expect Nestlé could try to take advantage of the brand recognition of Jenny Craig to begin selling an expanded line of meals through supermarkets and other channels, where Nestlé can use its scale and influence to command premium shelf space. And the market for diet-related products is growing at almost 10 percent a year.

For Nestlé, which already owns Lean Cuisine, the deal will bolster its position against rivals like Unilever, which sells Slim-Fast packaged meals and shakes — a business that is growing at double digits — as well as Weight Watchers International and ConAgra Brands, which owns Healthy Choice.

The deal also marks the first time a major food manufacturer has made such a big bet on a business that is not strictly about selling food. Much of Jenny Craig's appeal lies in the personal evaluations and tailored diets that it offers clients, as well as the weekly workshops at its 600 centers in the United States, Canada, Australia and New Zealand, where dieters come to get motivated. Indeed, if Nestlé pursues a supermarket strategy with Jenny Craig, it may face a huge challenge: Jenny Craig stumbled in the late 1990's, in part, because it too began selling food and diet products outside of its centers, a move that was blamed for confusing the brand among consumers and driving down sales.

Nestlé won a long-running auction for Jenny Craig, which was put up for sale in January by its owners, ACI Capital and MidOcean Partners, a spinoff of Deutsche Bank's private equity arm. The private equity firms had acquired a majority interest in Jenny Craig from the company's founders, Sid and Jenny Craig, in 2002 for $115 million. The sale is a major coup for the firms, which reaped more than five times their investment in less than five years.

Jenny Craig's turnaround has been dramatic. When ACI and Mid-Ocean bought the company, it was suffering from a string of image and fiscal problems. The company had just been delisted from the New York Stock Exchange and was forced to close more than 100 stores as it continued to lose sales to the fitness craze and a free-for-all of new weight loss products sold on the Internet. It lost a $15 million lawsuit for selling the fen-phen diet drug combination in 1997 and suffered a public relations blunder in 1999 when it hired Monica S. Lewinsky as its spokeswoman, only to fire her after a firestorm of controversy.