Sainsbury's has reined back plans for new stores and said the change in plans has affected its balance sheet.
The supermarket chain took a charge of £287m because some sites will no longer be developed.
The firm reported a half-year loss before tax of £290m and said that like-for-like sales had fallen 2.1% during the period.
It expects like-for-like sales in the sector to be negative "for the next few years".
"We anticipate the next couple of years in our industry will be extremely challenging," Sainsbury's chief executive Mike Coupe told BBC Radio 4's Today programme.
"The reality is we are seeing deflation for the first time in probably around 10 years," he said.
A change in shopping habits was affecting supermarket sales, Sainsbury's added.
People were shopping more frequently and using online, convenience and discount retailers more, it said.
Sainsbury's said it had "robust plans to address this challenge", including investing £150m in price cuts.
In the half-year, Sainsbury's said it had taken total one-off charges of £633m, including £287m for altering its store opening plans.
"We are acknowledging we are not going to build out as many large supermarkets as we were anticipating, so that results in the fact that the land becomes less valuable," Mr Coupe said.
The firm also took a charge of £341m in relation to existing unprofitable and marginally profitable trading shops.
Source : Click Me