Hello there and thanks for posting

I am sorry to hear about your situation and appreciate to hear you may be pre diabetic must be an added worry.

There is more information about this here and some simple changes that can be made to reduce this risk but you may not need to completely overhaul your diet, so do talk to one of your doctor or nurse about this, to see what they suggest. 

There are some patients who are at greater risk of complications when undergoing surgery and whilst people who have diabetes may need to be managed differently prior, during and after surgery, having pre diabetes alone is unlikely to impact your surgery in any way. From what you have said otherwise you are healthy, eat a balanced diet and your weight is in healthy range which is all good.

I hope this helps but do get back in touch if you have further questions.

All the best

Naomi