I have been on a keto diet for almost 2 years (Oct 2017). I started experimenting with keto in Aug / Sept after watching Dr Sarah Holmberg's Tedx talk on reversing diabetes. A little background, In July 2017 I was diagnosed with pre-diabetes. My A1C was 5.7 in 2017. In 2016, I had an NMR lipoprofile cholesterol test which also measures insulin resistance with the LP-IR test. I measured a 58 that year where anything above 45 is insulin resistant and indicative of diabetes. In 2016, I don't recall my doctor mentioning anything and I did not get my A1C tested that year. I am 5' - 5" and weigh 128 pounds. I have run either a half marathon, full marathon or both most years since 2011. So weight and exercise was not an issue. I still weigh about the same but based on both calipers and the navy tape method, I have reduced body fat % especially around my waist since starting the keto diet.
For the first 6 or so months I was very strict. Now I would estimate that 95+ % of my meals are keto.
My clinical results are in
2016 my cholesterol was 267 total, ldl - 179, hdl - 69, tri - 96, tasted blood sugar (fbs) - not tested, A1c - not tested, LP-IR 58
2017 - Total - 218, ldl - 124, hdl - 67, tri - 135, fbs - 109, A1C - 5.7, LP - IR - not tested
2018 - Total - 237, ldl - 143, hdl - 83, tri - 54, fbs - 103, A1C - 5.1, LP - IR not tested
2019 - Total - 246, ldl - 141, hdl - 92, tri - 64, fibs - 110, A1C - 5.5, LP - IR 25
So my total cholesterol and ldl still run a little high, my triglycerides are down 50%, and my HDL is up 50%. My doctor is very happy with my cholesterol numbers. My fbs runs a little high. I have found that if I eat a breakfast with zero carbs my blood sugar drops below 100 within one hour. If I have carbs with breakfast my blood sugar will increase 20 to 40 points within 1 hour depending on the curbs. Based on this, I only skip breakfast after "cheat" meals to return to Ketosis quicker. When I skip breakfast, my blood sugar remains above 100 until I eat. My A1C and LP-IR are both considered normal and I am no longer clinically considered pre-diabetic.
On a non-clinical level, I definitely feel more energetic when I am in Ketosis. I don't really notice a difference with one cheat meal but if I have a cheat week (vacation) I can really feel a difference by the end of the week.
As far as alcohol goes, I have confirmed with testing that dry red and white wines do not affect my blood sugar nor do they kick me out of Ketosis, so my wife and I will split a bottle several times a week which is a couple of glasses each.
Sorry for the long post but for those of you with diabetes or pre-diabetes, I wanted to share my story especially since my positive results do not include weight loss or increased exercise so are strictly based on keto diet. Weight loss and exercise have also been shown to be beneficial.