You just touched all of my buttons wrt food and economics here.
First of all, just because food isn't used doesn't mean it is wasted. I don't like to go to the store all the time so I buy more food than I may end up using -- but I still consider it worth it.
Second there is not an limited amount of food in the world and there is no reason we have to cut down on our use in order to feed hungry Africans -- we can, as GP correctly pointed out -- feed the entire world.
At this point the only reason there is hunger anywhere in the world is bad governments and failed states -- Haiti is hell on earth (and has been before the recent earthquake), but it borders the Dominican republic, which is much better (if still far from the western world), NK is the worst place on earth with street urchins scavenging for single kernels of rice in animal dung, SK, which it borders, is a pretty good place to live and has basically no starvation.
It is one country today, but the same difference (albit to a lesser degree) could be seen between East and West Germany.
Finally, take the recent hunger situation in Africa -- people had to walk miles through the desert, leaving their dead and dying children behind in the sand because they couldn't carry them. They had to walk until they came out of Somalia and entered Kenya where they would receive held and food -- because the warlords of Somalia didn't allow the food aid into the country as they believed it was a western emperialist attempt to make Islam look bad.