The rise means the average UK household is facing a jump of £643 (€730) in their annual grocery bill, to £5,265 (€5,982), if they continue to purchase the same items.
With consumers looking to manage budgets, sales of supermarket own label lines increased by 8.1% in September, while sales of branded lines, which are generally more expensive, fell by 0.7%.
The market researcher said grocery sales rose by 4.8% in the 12 weeks to October 2 year-on-year - masking a much larger drop in volumes once inflation is accounted for.
“People are pretty savvy at seeking out best value and retailers are expanding their ranges to help them do this," commented Fraser McKevitt, head of retail and consumer insight at Kantar.
Cheaper Ways To Cook
Faced with soaring energy bills, Britons are searching for cheaper ways to cook as they try to avoid using their ovens, Kantar said.
It said sales of cooking appliances including slow cookers, air fryers and sandwich makers, which generally use less energy, rose 53% in the four weeks to September 4 year-on-year.
Kantar also noted that sales of duvets and electric blankets increased 8%, while sales of candles increased 9%, suggesting people may be preparing for possible winter blackouts.
Last week, department store chain John Lewis said Britons were stockpiling thermal underwear, gloves and dressing gowns.
Lidl Leads The Charge
For the fifth month in a row, discounter Lidl was the fastest-growing grocer, pushing up its sales 20.9% over the 12 weeks, marginally ahead of rival Aldi whose sales rose 20.7%.
Sales at Sainsbury’s rose by 3.0% and at Tesco by 2.5%, while Morrisons saw sales fall by 3.9%.