Keep carbs, dairy, gluten, moldy foods, low. I canít speak to ACV anymore, as the fermentation will either help or hurt, based on specific condition. I used to drink ACV straight, drink kombucha, eat yogurt. However, I may have been feeding the beast.
Fasting a bit doesnít hurt, but I am guessing your body is starved of nutrients already. Only do it intermittently, for short periods.