It is understood that agencies were asked to present ideas that did not include the brand's spokeswoman, Fern Britton. The celebrity came under fire last year for having used a gastric band to lose weight.
Grey will begin working with the client immediately. However, it is not yet known whether it will be briefed to use Britton in future campaigns. The process was handled by Carol Welch, the marketing director for Jordans and Ryvita. She said: "We're delighted to be working with Grey. The ideas they presented for taking the Ryvita brand forward were fresh and exciting. Grey managed to build succinctly from our brief and add value to our existing brand equity."
Mortimer Whittaker O'Sullivan previously handled the business, which it won in 2004 without a pitch.