Food for the journey

Clearly, the Elf that created Lembas never met Hobbits.

Okay, so I'm going to try something and probably fail at it, but I'm going to try and create stats for Lembas-like foodstuff that could be used in a D&D or other OSR games.

Item: Wayfarer's Bread.
Description: White in color and baked into a small square, Wayfarer's Bread is a staple food for both travelers, adventurers, and armies. Made using a recipe once held secret, but now widely disseminated, Wayfarer's Bread differs from regular bread in that it can last several months if properly stored and is more filling. One square is capable of fulfilling a person's hunger (but will not fill their belly) for a day, unless that person exerts themselves behind a certain point, which decreases the effective of the bread by up to half. Naval forces use a variation of the bread, called Seafarer's Bread, which is made from a recipe adapted to sea conditions.
Stats: ????
Effects of Wayfarer's Bread (and it's derivatives) can be negated and decreased through spells, curses, injuries, and exertion.

As you can see, I've hit a bit of a wall. I have no idea how to do the stats. Thoughts?

Gifs via my Alex Trager.