I've often wondered about this. It's interesting to see a study that shows in detail how wasteful we are as individuals.

BBC: Food waste on 'staggering' scale

People are needlessly throwing away 3.6m tonnes of food each year in England and Wales, research suggests.

The Waste & Resources Action Programme (WRAP) found that salad, fruit and bread were most commonly wasted and 60% of all dumped food was untouched. The study analysed the waste disposed of by 2,138 households.

We all know that restaurants are terribly wastful of food, but I think very few people realize how much food goes to waste in their own homes. I would wager that this total is far higher in the US due to diffent cultural ideas of food as well as simply a larger shipping network, meaning that foods spoil in the fridge sooner because more of their life is spent in transit.