Running up to 8 miles a day on rolling 72s sounds extremely dangerous to me. Your hydration and minerals will be impossible to manage properly, and the amount of metabolic water won’t get close to protecting you from the impact of what you’ll perspire and exhale on 8 mile runs.
If this is something. you are interested in doing I would recommend doing 15-20hr DF with your. runs and then move on from there. I have been doing this for a few weeks (after lots of 1, 2 and. 3 day dry fasts). I have finally gotten to the point where it is completely normal for me to not eat or drink for 15-20 hours and then go for a 3-8 mile run.
If dry fasting and running are something you are wanting to combine and be efficient at, I HIGHLY recommend breathing exclusively through your nose while running. The transformation process takes about 4-6 weeks, but once you become proficient it will conserve 50% of your water that you would otherwise lose through mouth breathing. Check out Oxygen Advantage (on youtube or google) to learn the science and techniques behind it.
Once your body gets adapted to dry fasting and running, you will be just as, or more, proficient than before. My max run was a half marathon on a mountain with over 6,000 ft of vertical climbing and I got the CR on strava so it was pretty fast (all while dry fasting…)
Hope this helps, but seriously, if you are going to do this, you. should really breathe through your nose exclusively (if you don’t already…)
Eat Some salt about a quarter teaspoon whenever you fast longer than 24 hours especially if you’re doing cardio. If you want to lose weight quickly go keto and do unilateral Calisthenics exercises. Turmeric powder with black pepper along with ice therapy and cbd will heal the body during this intense time. Again if you truly want to lose weight quickly you gotta have a plan for the action and recovery.