Ob appt, too much weight and big baby

Yesenia
So before pregnancy weight was 184, which makes me considered obese. I was suppose to gain 20 lbs max and I'm at 27 lbs, at 28 weeks with 11 to go before baby boy is born. Ob wants me off sugar and limit carbs to prevent having a big baby, he was measuring 2.5 lbs at 26 weeks. Should I be concerned for a 10 pounder? Or she just being cautious.