Nausea when hungry?

[pomeerin 44]

I am pre-surgery and am very worried about the extreme low calorie diet I'll have to follow both right before and after surgery. If I go a really long time without eating, like 8 or more hours, I start to get super nauseous and I have to absolutely choke down food because the thought of it disgusts me due to the nausea! I feel completely better after about 2 or 3 bites. I don't think it's hypoglycemia or anything because my sugars test normal, but I'm afraid the low calorie diet will make me nauseous and I might hurt my new sleeve by puking up bile or dry heaving. Does anyone have any experiences like this?