Eating anything in moderation is fine. I usually have pizza every Friday. Just don't go overboard to the point where you eat pizza every night.
Enough to go from earth to the moon and back twice
once a week
they often eat pizza and hotdogs
it is very possible that Italian soccer players eat pizza but probably not often, so they can mantain a healthy diet.
one a week
once a week
She DOESN'T eat pizza. An easy way to check your choice is to remove the contraction. You would not say "she do not eat pizza," so you wouldn't say, "she don't eat pizza." On the other hand, "she does not eat pizza" indicates that "doesn't" is the right choice.
they eat mostly Pizza
"Did he eat pizza?" is the past tense.
To say 'I eat pizza' in Spanish, you would say 'Como pizza.'
about once every week