Great article in National Geographic about food waste. Every year about a third of the food produced in the world never gets consumed. They break it down interestingly into "loss" and "waste", loss being items not captured or thrown out during picking, sorting, storage, etc, and waste being items discarded in homes and supermarkets. Nineteen percent of all food is uneaten and discarded in homes. The only bigger source of "scrap" is the 20% lost during picking and sorting at the farm (most discarded because it doesn't meet aesthetic standards).
They also feature heavily Feedback, a global nonprofit that works to put in place solutions to food waste.