The agency will develop a new creative strategy and create in-store and outdoor activity.
Sarah Doyle, the brand director at Eat, said: "The food-to-go market is becoming increasingly competitive and we need an agency that can work with us to cut through an already crowded space.
"Fold7 stood out because of their approach to creativity. They’re the ideal partner to help us achieve our goals."
Harry Sheward, the managing partner at Fold7, said: "Eat is one of the original fresh food chains and remains a well recognised and liked fixture on many of our high streets.
"But with so many more players entering the market, Eat needs a 21st century approach to ensure that it isn’t seen to be standing still and its offer of fresh food that’s made from scratch continues to stand out from the competition."