YOU SAID:
I’m having pizza for lunch.
INTO JAPANESE
昼食にピザを食べています。
BACK INTO ENGLISH
I'm eating pizza for lunch.
INTO JAPANESE
私は昼食にピザを食べています。
BACK INTO ENGLISH
I have pizza for lunch.
INTO JAPANESE
昼食にピザを食べます。
BACK INTO ENGLISH
I have pizza for lunch.
That didn't even make that much sense in English.