Not sure how to answer that. I am not fasting. I am eating healthy and doing a Healers Who Share protocol for my health issues. Just finished a parasite and Colon Cleanse about a month ago and didn't have the leg problems. Asked Humaworm and he said that the leg pain/spasms, tightness, etc. are common because during such things as detoxing, toxins are being pulled out of the musles and joints of the legs.