Icon Books will publish Eddy Tumble & The Fast Food Fiasco next summer.
Although written as a light-hearted children's adventure, the 50,000-word story alerts youngsters and their parents to the issues of child obesity and warns them how addictive fast food can be.
Hills worked at Ben & Jerry's from 1998 until April 2001, joining as group brand manager and working his way up to marketing manager, the most senior marketing post.
He oversaw the brand's national launch in mid-1999, and remained during its integration into the Unilever empire. He quit when the owner decided to revert to US-style ads to attain creative consistency across all markets.
A month later he was hired by The Enjoy Organic Company as its first head of marketing, but was made redundant this summer when owner RHM decided to streamline the portfolio.