I would much rather see it be a consumable, with various different supplies you can place on the ship, in differing amounts.
Hardtack; cheapest, lasts forever, but crew don't like it; their morale will slowly deplete when out at sea.
Grain; cheap, made into bread onboard ship, lasts forever, offers no stat boosts; this is the "standard" food.
Citrus fruit; expensive, slight boost to morale, without it crew health deteriates over time (scurvy), making them weaker in battle, and possibly leading to "deaths" (incapacitated by illness) in extreme cases. Has a shelf life of however long fresh fruit lasts.
Jerky; expensive, lasts forever, provides a slight boost to morale.
Live meat; very expensive, lasts forever, but takes up some cargo space and consumes grain. Provides a good boost to morale. Is lost if grain runs out.
All stats are reset to base level when returning to port. Any crew who are left unused in port for more than a couple of in-game days are given a temporary "shore leave" boost to morale when you set sail again.
Hardtack and grain would be available at every port. The rest would be available in the same way as resources are.