Over population is a myth. There is currently enough food to feed 10 billion people, and we are only at 7. While world population continues to grow, the growth rate continues to drop. Recent developments in Africa might result in a national population explosion, but that too will eventually settle.
By increasing health standards (more food) people will fall back to having food shortage again (more people). While this is true, it does not make it wrong to help. Many things can change in the course of years and the world could look different in a few decades.
With development of new techniques of how to store and produce food and GMO's efficiently, the world's economy and agriculture could look very different in only a few decades, rendering the problem obsolete. We may even colonize mars this century.