How can I encouraging variety and diversification in food production?

I am planning a colony builder game, and one part will be food production. There will be a variety of crops available, but in the end they all serve the same purpose, feeding the inhabitants.

Many games offer different grow rates/yields for different crops, but this is a rather unsatisfactory solution, as it can easily lead to an ‘optimal’ crop, that then gets planted exclusively.

Instead I’d rather encourage having planting a variety of crops, since people like having a selection and not eating the same food all the time. On the other hand, I’d rather abstract away different kinds of food as much as possible, to not overwhelm the player with tracking a multitude of near identical resources.

Does anyone know of good methods on how to track the ‘variety’ that goes into a resource?