I have always been a lean guy my entire life. Never been bigger than 140 lbs on a 5'7" frame. These last 6 months I've been running a consistent 120 miles a week but for whatever reason I'm still the same weight. I went from my usual 135 to 130 lbs at which I've been stuck at. I know I still got about 10 lbs to lose before I'm medically considered "underweight", so how can I lose that? I know that would make a huge difference between my PR of 14:34 and goal time of 14:10 in the 5,000.
I don't touch weights. I eat about 5000 calories per day on this training program, about 1000g of carbs and never more than 10 grams of fat a day.