I allow it, though the rules are vague on this.
My general thinking was: Inventory should prompt meaningful choices, but not be a burdensome chore.
I think forcing PCs to carry rations for survival and additional rations for healing is a kind of punishment.
Also, if healing spells are common in your setting (or you just prefer them) you could treat them like rations, but maybe say they are small and 2 or 3 fit in a single slot.
You're the DM, it's up to you! :)