You can’t solve world hunger just like you can’t put out a fire with gasoline. I you feed a population, you have to feed it again, and again, and again, al the while it is growing...
You can “solve” it, in a sense, by equipping and enabling men to provide for their families.
The poor we will always have with us. But we needn’t have so many. A just peace, fair contracts, the right to work, good trade policy, capitalism will do it. 6 billion not required.