My experience has been, when starting a low-carb diet, that my fasting blood sugar numbers went down and were in the 80's. However, even continuing the low carb diet, they rose within a month to between 100-110, even though my glucose control was steadily improving. I t was not until I did intermittent fasting with my "eating window" encompassing breakfast and lunch (rather than lunch and dinner as many do) that my fasting blood sugars returned to the 80's or low 90's.