Cash-strapped workers are shunning shop-bought sandwiches and making their own packed lunch, Sainsbury's.
Shoppers trying to survive the credit crunch are also spending less on takeaways and making home-made "fakeaways" of their favourite dishes, according to Sainsbury's.
The supermarket chain said sales of plastic lunch boxes have shot up by more than a third (36%) in the past month and sandwich bag sales have also risen by (25%).
More than a third (37%) of people questioned in a poll for Sainsbury's said they were spending less on takeaways and 15% said they had stopped buying them completely.
The YouGov poll of 2,000 people found more than a quarter (28%) said they often used leftover meat and vegetables in either home-made curries or stir fries.
And almost a quarter (22%) said they were trying to make better use of their leftovers as a direct result of the credit crunch.
A fifth (20%) said they now threw away less food.
Sainsbury's said sales of "fakeaway" ingredients including curry pastes, poppadums, coconut milk and naan breads have all risen.
Alison Austin, the environmental manager for Sainsbury's, said eating home-made sandwiches and using up leftovers in meals can be a good way to save money.
"The cost of a home-made sandwich, using ingredients from the fridge and bread from the bread bin, is substantially lower than the prices at sandwich chains.
"Buying the ingredients on the weekend and planning ahead or using leftovers can save a huge amount."
She added: "Fakeaways are here to stay. They're created for a fraction of the cost of traditional takeaways, you know what's going into them and they use up food that would otherwise be chucked out and sent to landfill."
Sainsbury's estimates that a fortnight's worth of sandwiches can be made for the same price as one shop-bought lunch but the rise in home-made lunches does not mean sandwich sales are falling.
Jim Winship, director of the British Sandwich Association, said there have been no reports of a drop in sales.
"When things get tough, what tends to happen is some people make their own but other people who perhaps used to go out to pubs and restaurants start buying sandwiches.
"There's bound to be a move as people tighten their belts but the sandwich market seems quite insulated."