Nil.
When I was first diagnosed age 19, drinking was the thing to do at that age. I tried twice after being put on insulin, and both times ended up in an ambulance. Both occasions involved just a couple of bottles of Pils ( because of it's low sugar content) and a vodka and diabetic lime juice, again because I was told there's no sugar in spirits.
Both times I was sick and passed out, and had my stomach pumped out in hospital. I was advised that alcohol and sugar are two of the worse things for a body to deal with, and whilst one OR the other is tolerable, both can be just too much for some people. Based on my experiences, the medical advice was don't try and drink alcohol.
31 years later, I don't even remember what I'm missing, and my wife doesn't drink either so it's no problem for me.