Foodeffect works on player and pet
HP +20
VIT +3
Att +16~17% (cap: 72 / pet cap: 113)
Ranged Att +16~17% (cap: 72 / pet cap: 113)
I just tested it with Fenrir and my lower level wyvern to confirm the percentage. The caps are somewhat strange, but a LS-mate also got capped +72 att, so I assume the cap for pets is also correct despite it being slightly odd.
Confirmed r.att with automaton