Losing weight after tonsillectomy

I (18F) am hoping to get a tonsillectomy soon, because I have been sick every single month for the last six years with an awful sore throat.

I have heard alot of people saying they lost alot of weight while recovering, due to not being able to eat. Like crazy amount of weight loss within two weeks.

I have always been very close to being underweight, so it makes me nervous if i can’t eat properly after the surgery, and might lose weight.

Sure it’s nice to lose weight so easily, but I seriously dont want to lose weight during recovery. I have had anorexia on and off for the past few years, and losing weight could trigger it.

I also had a thought, can the doctors say no to the surgery if you’re underweight? It’s kind of a ridiculous question for such a minor surgery but I’m curious.

Anyone who have experienced weight loss during recovery? Any tips for not losing weight while recovering?