Quarterly food sales were up 0.5% in February - the best performance since January 2014.
Despite this, like-for-like sales for food were down 1.6%, according to the British Retail Consortium (BRC).
Joanne Denney-Finch, chief executive, IGD, said: “With energy and ingredient cost reductions continuing to work their way through the supply chain, food retailers have been buying and selling at lower prices.
“So although February’s food and drink sales figures were almost identical to last year’s, it means shoppers are investing their savings back into better-quality groceries – helping to boost volumes. Our ShopperVista research shows 31% of shoppers now say product quality is extremely important when deciding where to buy their groceries, compared to 27% who said the same last year.”
The organisation said the growth in food sales was broad-based, with holiday-related products and gift items topping the charts.
Helen Dickinson, director general, British Retail Consortium, said: “Fundamentally though, sales are up while prices fall, which means that retailers are continuing to work hard to provide original products that excite customers at the right price. So far, 2015 has been positive for both retailers and consumers and it shows no signs yet of changing course.”