I, too, am slim and when I was diagnosed in April of this year, I started LCHF, despite my doctor's anxious cry of, " but you haven't got any weight to lose." I lost 9 pounds and have stabilised at 8st 2lbs which is still inside the normal BMI range. My blood glucose readings are reasonable, usually 5s and 6s. I don't count calories but I do try to have a period of intermittent fasting during the day ( no breakfast, e.g.). Perhaps LCHF with IF might suit you better.