You all sound much more knowledgeable then I do. I struggle with fasting mightily. What the few months of periodic fasting has been for me, is difficult. I was not able to fast for more then a few days, 2-3, before I got a feeling like a ball of fire in my stomach. I tried Apple Cider vinegar, it does work, but as a preventive, due to my messed up lining on my stomach, I went to a nutritionalist, she advised I take this Herbal supplement, called Digestron, http://www.chi-health.com/Products/DIGESTRON.html.
After a week of taking this, I have no more "fire" stomach issues. Just wanted to through this out there, to share what has worked for me.