Friday I had a ketone BOHB (B-hydroxybutyrate) level of .4 mM/L. This is not quite at the level of nutritional ketosis although some ketones are present. Saturday I ran 25.5 miles. No breakfast before hand due to time constraints :(. I did have 2x servings of Super Starch by UCAN http://www.generationucan.com/plain.html and a caffeine pill. I then ran 5 miles at 98% of my maximum ability. So ketosis promotes fat burning over carb burning but at higher intensities a significant portion of calories used still comes from carbs. So figuring that I used up all of my available carbs in the short 5 mile burst I attempted to drink another 1/2 serving of UCAN. This quickly induced a stomach ache. In addition I badly needed a restroom for my morning movement. This restroom came an agonizing 7 miles later. My stomach ache lasted until mile 23. After about mile 8 I had difficulties running up the hills and at mile 20 difficulties running down the hills. This was intended to be a nutritional experiment but I’m afraid I handled it quite poorly from start to finish.