Simply get someone with cooking and use Fish Feast - Item - World of Warcraft or Great Feast - Item - World of Warcraft (great feast not tested) while hes in your party.
If you have high lvl cooking on your main character and you want feast buff on your alt you can:
1. Tell someone to inv your main and put feast on ground
2. Alt+F4 out of wow and fast log to your alt and get inv to same group with your main
3. Eat feast and get well fed buff
This is obviously not intended because other self used foods have level requirement.
Sry if this is repost but i tried to search and found nothing