If there are different types of food, they should do something. E.g., easy-to-use recipes for meals each night that grant you small bonuses on the next day. +1 to dexterity checks, +1 on concentration checks, start the day with 1*level temp HP, etc.

Otherwise, what's the point? It should just be supply packs.

Alternatively, perhaps supply rations could be infinitely purchasable and relatively cheap from vendors, but they don't taste good/aren't quite as healthy. So using supply rations gets you a malus the next day (-1 to attack rolls & save DCs, -1 to [ability score] checks, etc), while using actual food/meals doesn't. This would prevent soft locking via not having enough food to rest, but you'd be encouraged to rest at the frequency you find actual food to make meals of.