Makinus... Just Modify the Terrain in the Biq to have the amount of Food you want for each Terrain. For example, You can set some of the Terrain as 0 Food.
As far as I know, the "Food Box" is not adjustable.
If you do not want Population to grow even faster, Do Not allow "Doubles City Growth Rate" located in "Improvements and Wonders" in the Biq.