The world's biggest economies are set to gather for a G20 meeting next month, where they will decide whether action is needed to bring down soaring food prices.

But while some struggle to put food on the table, research shows that the average American throws out about 180kg of food every year.

About 40 per cent of all the food bought in the US ends up in the bin. Now, some inner city farmers are trying to help by recycling the waste into fertiliser to grow more produce.

As part of our "Feeding the world" series, Al Jazeera's John Hendren reports from Chicago.