add skeleton/martian/bugman/fishman to monkey cheese burger effects

[The Grim Sleeper]

Give people a reason to eat and give the chef opportunities to use those devious packets of syndicate sauce.

... Maybe have it throw in a random neutral/bad mutation as well, but nothing too crippling. I'm thinking speech filter, mostly.

I very much like adding non-neutral effects to food, as an incentive for consumption. But if it is all neutral with a slight chance of bad, people will still shy away from it.
Yes, there is the odd healing effects, and sometimes chem:stimulant effects of sugar/chocolate, but atm, still very few people willing to risc it.
Add a few minor beneficial effects like telepathy, empathic thought, Dactyl Crystalization or Photokinesis.
Musculature Enhancement would go great with some sort off steak diner or protein shake.