Customers leave the Whole Foods Market in Boulder, Colorado May 10, 2017. REUTERS/Rick Wilking

(Reuters) - Hedge fund Jana Partners added a fifth nominee to its slate for Whole Foods Market Inc's WFM.O board, as it heaps up the pressure on the upscale grocer to boost profits and lift its sagging stock.

The activist investor nominated Celeste Clark, who once served as chief sustainability officer at Kellogg Co K.N, to join the slate that already includes former CEOs of Gap Inc GPS.N and Harris Teeter Supermarkets as well as a stock analyst. (bit.ly/2qxnVJk)

Jana, which currently owns an 8.2 percent stake in the Whole Foods, has been urging the company to shakeup its management, boost profits and lift its stock price, which has fallen steadily since peaking in 2013.

In response, Whole Foods, earlier this month, named a new chief financial officer and five independent directors who were not on Jana Partners’ slate and offered two board seats to Jana, which the activist investor declined.

At the time, the grocer did not strike a standstill agreement with Jana, a source told Reuters, meaning the hedge fund can continue to pressure it to improve performance.

Jana can still nominate that slate at the next Whole Foods annual meeting, expected in February.