guò (過) is an experiential marker. It can be used to recount one's past experiences.
我去過中國。
wǒ qù-guò zhōngguó
‘I’ve been to China.’
Therefore, due to the nature of this grammatical marker, guò (過) cannot be used along with the habitual tense implied by frequency adverbs. Hence, it is grammatically incorrect to say *他常常吃過牛排.
