Food should only be able to be consumed outside of battle. It takes you longer than 6 seconds to eat an apple or a loaf of bread after all. :P
Definitely, but this still fails to address the larger issue. With unlimited rest and a large supply of healing items, attrition is no longer a balancing factor. You can be full health/power every encounter. Larian actually uses individual boredom threshold as a balancing mechanic, which is atrocious game design.
Even if resting mechanics were unbroken and the healing food items somewhat balanced to only work outside combat, they would still be "unimmersively magical". Yet another of many cheesy features that belittles both D&D and makes a joke of the game. It would also contribute to more annoying inventory clutter and micromanagement.
Larian could avoid this by abstracting the healing process. For instance by giving players/all biological entities a slow innate regeneration, or possibly make slow regeneration a passive Tadpole-power, or by having one food item be enough to start this slow regeneration (but eating more wouldn't speed up the regeneration). Larian could do well to remember the principle of KISS (keep it simple stupid) to reduce their needlessly convoluted homebrew mechanics/features that seem to take precedence over the already complex D&D system.