We should always build two markets, one for plebs and one for patricians.

The first thing we do after building a market is to disable ALL food types.

Then when we are ready we gradually allow the food types just enough to upgrade to the next tier.

For example, for plebs, we allow wheat only so they can upgrade to tier 2 house. When we are ready to upgrade them to tier 3 we allow onions and carrots. This way we can avoid wasting ton of food when we are not ready (or do not want to) upgrade the house.

This is especially important for patricians as we do not have enough workers to make enough bread at the beginning, so we do not want to waste any bread when we couldn't upgrade the house anyway.