Further testing the food option doesn't actually work. On a new game it gives you 9999.0 food per turn on your next turn. Disable food option and the next turn your food goes back to it original state. Just wonder if you could change the food option to give you a certain amount of food instead of food per turn?
Actually that wouldn't work for food. The game doesn't store food. So if you have an food production of 12 per turn you don't build up any food storage. Food is a use it or lose it supply.
So you need to keep the trainer on all the time or at least turn it on when you want to build any buildings that need food.