There's just one simple answer, but a huge task to enforce it! Raise the generation gap by increasing the average age worldwide which any child bearing woman has her first child. Succeed in raising it by just one year over the next 100 years and I'm sure that would slow it down enough to make quite a big difference to the level of future famine in this world.
Population growth control
Everywhere needs to limit the amount of children born, some may think it unfair, but it is the only solution. If they don't agree, their 8 or more children wont have a very good place to live.