In the United States, under 3 percent of municipal food waste - so that's the food scraps that goes into people's garbage cans - actually gets recycled. If you go to a place like South Korea, the exact reverse is the case. It's about 3 percent that doesn't get recycled.

In Kenya, where there isn't the luxury of feeding grains to animals, livestock yield more calories than they consume because they are fattened on grass and agricultural by-products inedible to humans.

We domesticated pigs to turn food waste back into food. And yet, in Europe, that practice has become illegal since 2001 as a result of the foot-and-mouth outbreak. It's unscientific. It's unnecessary. If you cook food for pigs, just as if you cook food for humans, it is rendered safe. It's also a massive saving of resources.

Once food gets into our fridges, larders and kitchens, ensuring that it gets used up before going off seems like an obvious thing to do - but it's alarming how many millions of tonnes are simply chucked because we don't keep track of the food we've spent our money on.