Anglian joint MD Bob Surridge said the chain was unable to achieve economies of scale because companies such as Tesco - and even the co-ops - were paying prices for property that it couldn't match.
"It was a very hard decision, but we simply can't take on increased expenses and utility costs if we have no extra stores to absorb the costs," he said.
The c-store chain, which recorded sales of £20m in 2005, had hoped to expand its portfolio from 20 to 25 stores by June 2006 - but failed to acquire any sites.
Last September, Surridge told The Grocer Anglian
had been eyeing a store in Horsford, near Norwich,
but was beaten to it by - ironically - East of England Co-op.
The sale of Anglian is the latest in a run of deals in which an independent retailer has been absorbed into the co-operative movement.
Last month, Midcounties Co-operative snapped up Stars News Shops while in August Southern Co-operative Retailers acquired RNS Partnership.
Surridge warned that Anglian, number 38 in The Grocer Top 50, wouldn't be the last retailer to fall into the hands of the co-operative societies.
"Companies like us are really struggling. You could argue that consumers will miss out in the future because companies like mine won't exist. The government needs to decide what sort of high street it really wants."
The deal will come as a blow to Nisa-Today's, which is losing one of its key members - Anglian and Nisa-Today's had worked together to launch a joint fascia in May 2005.
The deal increases East of England Co-op's portfolio to 137 stores. The Anglian stores will be rebranded as East of England Co-op Foodstores.