I was interested in that bit too!
I was overweight from age 8, obese in my early teens, morbidly obese (BMI over 40) by my late twenties and diagnosed with T2D at age 34.
Having now been T2D for 19 years and keto for 7 months, I have lost 4 stone (56lb) - and my last HbA1C was in the normal range (went from 62 to 40 in 3 months). And my BMI is still over 35… so maybe that early weight gain protected me? And, once keto gets my weight down further, I can fully normalise my BG, get rid of the spikes from occasional carb indulgence, and get off my metformin?