Agni is the power of digestion, stomach heat/gastric juices. You can fast and increase agni, which takes out toxins from the digestive system much the same way as a self-cleaning oven burns off old food spills. A long fast burns off ama (toxins), then agni goes to sleep once the toxins are gone. It’s good to give agni a rest every now and again. It takes about 3 days for it to shut down. Be sure to wake it back up before eating anything. Do this with lemon juice and spicy teas, simple cooked foods, avoid fats or dairy for several days.