To play devils advocate, just let them all starve and the population will balance out naturally. At the moment a lot of population growth is fuelled artificially by aid shipments.

People rely on the aid and have babies, if the aid wasn't there they'd either not have babies that they couldn't provide for or die.

Probably the best thing to do is stop all involvement in those countries and let them find a natural equilibrium, but that can't happen because all the western countries want the rich resources in those places so they create this vicious cycle.