What is the point of Whole Foods when you can buy gluten-free pie crust, organic sweet corn, and quinoa in most regular grocery stores? Whole Foods doesn’t seem to know, and neither do the people who used to shop there, which is why a major shareholder of the supermarket chain wants Whole Foods to clean itself up and see whether anyone might be interested in a merger.

The Wall Street Journal reports that today, activist investor Jana Partners and some allied companies bought almost a 9% stake in Whole Foods, becoming the chain’s second-largest investor. Jana Partners has big plans for the grocery chain. Those could include behind-the-scenes technology and operations changes to help it compete with standard grocery chains.

Other stores collect data on their customers and what they buy, something that Whole Foods is still only experimenting with in Dallas and in Philadelphia.

The firm considers Whole Foods stock to be “undervalued,” and thinks that bringing in fresh board members to turn things around quickly could be good for investors. The firm also plans to explore a sale. One recent rumor was that Kroger was considering buying Whole Foods, and other firms might be interested.

Investors in public companies want growth, but Whole Foods is no longer growing. Its same-store sales have actually been shrinking. Those customers may be shifting their spending to standard grocery stores, or visiting other natural-foods markets like Trader Joe’s or Sprouts.

“As most retailers know, once traffic has been lost those patterns rarely reverse,” a Barclay’s analyst wrote in a note about Whole Foods. (warning: auto-play video at that link)

That’s why the activist investors want to try a fast turnaround, getting those customers back before they get out of the habit of shopping at Whole Foods.

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