Drinking water without eating is not necessarily a way of starving, but also a hunger strike, which is a very dangerous behavior. Bigu is an advanced regimen, and you can't start it casually. If you turn into a hunger strike, it will do great harm to your health. Study for a period of time before crossing the valley, and then make preparations before crossing the valley, so that you can try crossing the valley for the first time. (Longteng Bigu)