The number of Sunday lunches eaten outside the home has increased by 22% in the past two years, says market research firm Taylor Nelson Sofres.
But, despite this shift away from the traditional family Sunday lunch at home, roast meals remain the most popular eaten out on a Sunday, with almost 42 million consumed over the past year.
Pubs and steakhouses are the main focus for the Sunday roast, holding a 66% share of the market.
The most popular roast is beef, accounting for 35% of all roast meals on a Sunday, followed by chicken (21%) and lamb (14%).
The research showed beef was more popular with the over-55s, but 16- to 24-year-olds preferred chicken.
Craig Thomson, assistant manager of the Wheatsheaf pub in Dallington, Northamptonshire, said: "It's a shame the tradition [at home] is dying, but we are getting busier and busier which is a good thing."