Can you tell me which is the correct option - ‘In spite of HIS/HIM being fat, he runs fast’ ?
I would say ‘Although he his fat, he still runs fast’ or ‘Although he is fat, he still can run fast’.[YSaerTTEW443543]
TOEIC listening, photographs: Working in a muddy field[YSaerTTEW443543]
If you have to choose from the two, then ‘In spite of his being fat, he runs fast.’ is the right choice. Or simply: ‘In spite of being fat, he runs fast.’ Another choice using ‘his’ is: For all his fatness/weight, he runs fast. By the way, words such as ‘fat’ do not go over very well with Western societies.
All writers have given you the right grammar and context .
If you like to know the simple grammar answer , after ‘of’ preposition you use
‘object pronoun’ that is him not his (possessive pro.)
Unfortunately, it is not the pronoun alone that is the object of the preposition, Minhajquazi, but the entire noun phrase ‘his being fat’. It is his fatness that could slow his running, not he himself. He ‘possesses’ the fat and so the possessive pronoun is the appropriate one.