I’m going to guess middle distance to be around 7-10 miles? This is the distance I am currently trianing at twice a week. Depending on when I run, I will have simple sugar carbohydrates the evening before (early day run) or for breakfast (evening run) at least 8-10 hours (12-16 hours preferably) before. I also consume low glycemic index carbohydrates 1-2 hours before the run to provide some energy release for after my glycogen store become depleted. I even take a few sports beans along with me to chew on for a quick fix to my sugar.