Take a road trip to the central valley and take a look at what's being farmed. Almonds. Cotton for mattress stuffing (too shit a grade for anything else). Lettuce. All very high water use crops that don't give you hardly any nutrition save for the almond.

There are dozens of crops that we can and absolutely should dispense with. The problem with agriculture is farmers don't farm what uses the least resources and brings about the most nutrients per land area, they farm what returns the most. We also subsidize a lot of these crops.