Jason Momoa took a break from the superhero diet on Friday to eat delicious human food ... stopping through Joe's Pizza in WeHo to get his face in some pie.

We're told Momoa rolled in with 4 dudes and ordered up a buncha slices including the Grandma Slice ... marinara, fresh mozzarella and fresh basil and topped with a drizzle of extra virgin olive oil.

Question -- if "Aquaman" orders anchovies ... is that like quasi-cannibalism?

Easy to see why Jason was smiling ... pictured here with the owner, Joe.

Abs are overrated anyway ...