About an incentive to diversify the food used, there is an idea in the game called ECO I like a lot :
- you're character gains randomly a demand of a specific dish time to time
- if you satisfy the demand, then you get a bonus
So it would be nice to have something like that in H&H imho. That could be balanced with accessible recipes, or dishes you already took at least 1 time.
We can imagine bonuses of different kind : reduced hunger of that particular dish when your character asks for it, bonus FEP, bonus Energy...