Why do you have chronic fatigue? For some people it’s because of overconsumption of carbs and/or caffeine. Do a strict low carb diet to lose the weight, and stop all caffeine consumption if you do get any. Fasting is the healthiest lifestyle for virtually anyone not skin and bones starving to death. So keep on doing IF even when you’ve lost the weight. To maintain just count your calories and macros and watch the scale. If you’ve put on a few extra pounds one week, then eat a little less the next week.