The 78-outlet chain, which operates c-stores and CTNs in the north of England, the Midlands and South Wales, will add the ranges in the autumn after feedback revealed shoppers wanted to do a full shop in their local store.
MD Nigel Mills said he was working on sourcing a fresh bread range and was talking to a number of suppliers. He was also looking at products for the meat and poultry ranges, as well as training staff.
"Shoppers want the opportunity to do a proper shop in their local stores," he said. "By offering a range of meals, frozen and chilled, we can help them do this."
The move marks a further step away from its origins as a CTN operator. It launched a convenience store model in 2005 and two years ago rolled out the concept to 19 stores through a new co-branded fascia with buying group Nisa-Today's.
Last November, Mills Group joined a handful of retailers linking up with the government's Change4Life pilot scheme in the north east of England, aimed at boosting the sales of fruit and vegetables in deprived areas.
"We are very much a convenience store operation," Mills said. "We have 27 CTNs but all of these have a basic food range. We are doing very well but would like to do better. Sales of alcohol, food, soft drinks and tobacco are buoyant."
Mills Group's decision to diversify early had paid off, he said. "Newspapers are still the number-one driver of footfall for CTNs and c-stores. Independent newsagents should make sure their offer is right for the customer. If not, they should consider diversifying into impulse or grocery."
This week Mills Group completed the acquisition of five stores from Sainsbury's, as revealed by The Grocer in April. They are expected to increase the chain's annual turnover of £55m by about 10%.