Whole Foods Market Inc.’s $565 million purchase of Wild Oats Markets Inc. doesn’t violate federal antitrust law and can proceed, a federal judge ruled, allowing the two largest American natural foods grocers to combine.

U.S. District Judge Paul Friedman declined to grant the U.S. Federal Trade Commission’s request for a preliminary injunction to bar the transaction yesterday.

Whole Foods agreed to acquire Wild Oats in February. The FTC sued in June, claiming consumers would be harmed by higher prices and decreased competition. The grocer will now own its largest competitor as it seeks to lure customers back from more conventional rivals such as Safeway Inc. and Wegman’s that are selling more natural-food products.

“They took a practical view of how consumers shop,” a partner at Eimer Stahl Klevorn & Solberg in Chicago, Andrew Klevorn, said. “Consumers look at Whole Foods as just one of many choices in the grocery segment.”

Whole Foods, based in Austin, Texas, jumped $2.28, or 5.5%, to $43.45. It declined 33 cents to $41.17 in Nasdaq Stock Market composite trading. Wild Oats, based in Boulder, Colo., rose $2.89, or 19%, to $18.

Whole Foods, which has 197 stores, would add 110 locations in 24 states and Canada by buying Wild Oats. Whole Foods was founded in 1980 and had sales of $5.6 billion last year.

In 1997, the FTC stopped Staples Inc.’s attempt to buy competitor Office Depot Inc. for $4 billion, saying it would harm competition in the growing market for office supplies.