The US has considerable agricultural surpluses If these surpluses were given to nations chronically in need it would?

A) solve the hunger problem in those needy nations.

or more likely,

B) fall into the hands of dictators and thieves who would then try to trade it, lowering the world price of whatever commodity they were selling, leading to problems in agriculture in America and other food producing nations.

In general, hunger and famine are rarely purely-natural disasters, there are usually grave political problems in countries which experience them. Just giving food is not enough. It is a temporary solution even when there is no corruption or diversion of the aid to the various factions.