That quote struck me as odd. What does the migration have to do with the price of food? If a meal really costs $320 in Sudan, I would imagine migration would be a much simpler solution to ending suffering. The migrant can just move to another country with better institutions and infrastructure where food is affordable. Migration may have other issues, but alleviating human suffering is one of the benefits.
Also, I'm not convinced there is a link between the percentage of food imported into a country and the price of food. If anything, food imports and trade would help decrease the price through specialization and trade.