In combatting world hunger, are you thinking of a factor other than price, like transportability, perishability, predictability, controlability, preparationability?

Given that the cheapest DIY soylent appear to be primarily based traditional staples like rice, oats, peas, soy, and flax seeds, it doesn't seem very likely to be cheaper. The initial price for the official one is $9/day, while the cost of the cheapest DIY based on traditional foods is $2/day.