My favorite way to practice IF is to fast 23 hours, then eat a huge meal over the course of an hour. My husband actually started IF to fix his hypoglycemic episodes. He'd already gone low carb which fixed about 50% of the problem. When he went to IF, he obtained complete control and totally lost all his "mental fog" symtoms. When he asked our primary care doctor about it, she said fasting was the best way to get blood sugar to come down and even out - no more reactive hypoglycemia.