Waste not, want not.
In the West, we throw away 30 per cent of the food we buy. A shocking waste, I'm sure anyone would agree.
But would you be willing to tuck into the cold pizza slices a stranger didn't fancy?
A free new app called Leftover Swap allows users to advertise their leftovers. They can browse leftovers in the area, and arrange to collect or have it delivered.
It started out by college students as a joke:
"It's obviously not for everybody," says co-founder Dan Newman. "But for as many people who seemingly have a problem with it, there's people who love the idea."
So do you feel guilty about the amount of food you throw away every week? And would you be willing to munch on a half-eaten meal?