It is well established that fasting is on the whole good for you. The duration of your fast can range from fourteen hours in a day, including sleep, to even a month or two. The first is called Intermittent Fasting; the latter is called as a Long Fast. A Long Fast can also take several forms. In one version, you do not consume anything at all, including food or water. In others, you end up drinking water but consuming no other calories from food or drink.
There are ways to cheat in which you drink protein broth and juice, but this is strictly not fasting since you are consuming calories; just in the form of liquids. The protein broth by itself is dangerous as the human body has not been built to live on protein alone. So would you do a Long Fast?
The answers are not that obvious. You will lose weight if you do not eat anything for say a month. Your glycogen levels will dissipate in a day after which your body will turn to protein and stored fat. While consuming the protein, your body will work itself through your muscles group and will not spare your heart muscles either. Parts of your heart will be consumed to meet the energy needs. Ultimately, your body will work itself through your fat stores and consume them till there is nothing left. If that is your goal, there are more optimal ways to achieve this.
There are benefits including autophagy, in the long term fast where your dead cells are consumed. Some people like to go on a long-term fast to break their pattern of consuming unhealthy foods, especially addictive sugars. Fasting this way is not for everyone, and often the risk of starving yourself to death or causing other damage would probably outweigh the benefits. Do you know someone who has done a long-term fast?