Yes it's completely normal. After my surgery everything smelled like top ramen to me. To this day, when I smell top ramen, it makes me nauseous. It's ketosis and it's normal during rapid weight loss.
I remember a few days after my WLS, my wife (who was getting the same surgery in a month) came home from school and made a grilled cheese sandwich while I was still in the liquids phase. That is when I noticed the greatly enhanced sense of smell.