If we have more than enough food to feed the hole world, than why don't we?!
Answers: obese people eat it all!
because we are too busy wasting money and manpower on silly wars to be worried about hunger.
I don't think we do, and wouldn't it be better to teach the rest of the world how to provide food and drinkable water for themselves?
Greed and Corruption is the short answer.
See Economic and Political History of the last 200 years for the longer version: hegemony, systematic oppression by those who enslaved and pillaged.
Why does it continue? There has been no penance whatsoever.
It's like me come to your house, setting it on fire, stealing your clothes and poisoning some of your food and yanking a few family members away, and eventually i say you are crap because your house is still half burnt and you are ill and cannot get ahead. The "me" in this scenario is Western Europe and the US.
Some factors that make it difficult to deliver food to those who need it:
People are spread out over a wide area and it may not be possible to figure out where all the people are at any one time and what they need.
The infrastucture might not be in place to get everyone enough food.
Many people don't have a way to store perishables (refridgeration).
Corrupt goverments may not allow aid, in an attempt to appear not to have a hunger problem.
The famine in Ethiopia in the early to mid 1980s is a good example of things that can go wrong.