easiest way to incentivize food variety without nerfing anything or making a bunch of new recipes would be to apply a small bonus for each new food type used.
say each unique food you eat applies a 5% bonus to the next food you eat, you would then see people eating the newbier foods at the beginning of each gluttony point to generate a healthy bonus before finishing up with their wheat/red cabbage cabbage cake or whatever other high tier foods, if the bonus was properly balanced the variance timer should keep people from eating to many foods and building to high of a bonus that would be overpowered.
using something like this would encourage using different foods while also keeping the option to power through gluttony by spamming a single food type at a greater resource cost.