Food producers are inactive, when they have a chance to sign in and use some turns, they make a bit, and food goes down for a little while, but then they have to back to real life, and food goes back up.
As a solution to this issue, you could simply offer to bombard my fert with all of the gordos you can create, thus increasing my food production, which will lower food costs, and in turn allow for tax empires to make more money as well by being able to use more turns. A rather indirect way to use gordos to increase your income.