Tesco has confirmed that up to 9,000 jobs are at risk across its head office and stores as part of efforts to "simplify" the business.
The supermarket said it expected around half of the affected employees could be redeployed to new roles.
Sweeping changes across the business will include a reduction in deli counters, with 90 stores set to lose the service altogether.
In addition to those directly employed by Tesco, the changes will also impact third-party caterers as the company replaces the hot food service in its staff rooms with self-service kitchens.
Jason Tarry, CEO of Tesco UK and Ireland, said: "In our four years of turnaround we've made good progress, but the market is challenging and we need to continually adapt to remain competitive and respond to how customers want to shop.
"We're making changes to our UK stores and head office to simplify what we do and how we do it, so we're better able to meet the needs of our customers. This will impact some of our colleagues and our commitment is to minimise this as much as possible and support our colleagues throughout."
Additional changes include reduced hours dedicated to both stock control and merchandising.
Head office workers are also facing cuts as the company moves to a "simpler and leaner structure".
However, Tesco denied reports that it will overhaul its in-store bakeries, saying that no significant changes are planned this year.
Responding to the news, trade union Usdaw's national officer Pauline Foulkes said: "This is devastating news for staff, who have played a crucial role in Tesco's turnaround project, contributing to 12 successive quarters of growth, solid Christmas trading and over a billion pounds of profit.
"We will enter into consultation talks with Tesco, where we will examine the business case for their proposed changes."