The position will not be filled and DBC will now be run by MD Chris Horne.
Ramsden was brought in as CEO of the Woodward Group in 2007, which was making a loss after the failed merger. He oversaw the sale of Woodward Foodservice to Brakes for about £22m in 2008.
Since then, DBC has steadily recovered, making its biggest-ever profit, of £2.3m, in the year ending March 2009.
Ramsden claimed the business had not lost a major customer in the past two years and had gained accounts generating an additional £35m of annualised turnover in the past 12 months alone.
The company recently hired new directors for strategy, buying, sales and marketing and finance to support Horne.
"I came in to sort out a troubled business that was suffering major losses of both money and customers," said Ramsden. "DBC now has an absolutely first-rate top team led by Chris Horne, who has worked alongside me in that role since 2007. It is well equipped to take advantage of the significant growth opportunities we have identified as the business continues to develop its high-street customer base. I feel the job I was recruited to do is now complete and the time has come to seek new opportunities."
DBC was bought for £1 in May by three Iceland Foods board members CEO Malcolm Walker, FD Tarsem Dhaliwal and MD Andy Pritchard from its Icelandic owners, Baugur and Fons Eignarhaldsfelag.
Dhaliwal, who is also chairman of DBC, said Ramsden was a "textbook example of how to work yourself out of a job".
"Andrew will leave us with our highest recommendation and we wish him every success in finding and tackling a new challenge commensurate with his talents," he added.
Ramsden, who will leave at the end of the month, has worked at Northern Foods, Arla Foods UK and Grampian Country Foods.