Eating a Varied Diet
The quest is unlocked after completing The Future of Hyrule scenario.
"Following Daruk's advice to bulk up by eating lots of different foods, Yunobo is looking to mix it up and try something that isn't Rock Roast. Is there anything that might satisfy his appetite?"
"Having eaten his fill of strange stones, Yunobo felt power surging through him like never before! He swore to put this strength toward protecting not just Goron City, but all of Hyrule."
- Yunobo: Enhanced Ability