There are no very hard-and-fast rules as to when to fast. Some people observe fast for a day once a month; others do not observe any particular system and undertake a fast when their system needs cleansing. The following points may be useful for observing a fast:

1. Do not eat any food during the day of fasting. Drink as much as clean water as you can when you feel thirsty. Water cleans the entire system and washes away the impurities which might have accumulated in the system from time to time.
2. If in the beginning you find it difficult to observe complete fast for one full day, you can begin with a partial fast. Do not take anything during the day except water. In evening, take juice, fruits, or milk. That is to say, take no solid food except fruits.
3. Those who cannot observe even a partial fast may drink orange or some other juice thrice a day. Vegetable juice can also be taken in the absence of fruit juice.
4. It is essential to cleanse your bowels in the morning. It is better to take an enema of simple water, after the normal motion to cleanse the bowels thoroughly. Your fast will do you good when you start it with clean bowels.
5. Fast should always be broken with a glass of fruit juice. In the absence of fruit juice, you can take fruits which are pulpy and easily digestible, e.g., orange, pappaya, grapes, apple, etc. It is a bad practice to break the fast with a solid, hard or fried food like prantha, purl, sweetmeats, etc. In fact, it does more harm than good. It will be good to eat easily digestible food for two to three days after the day of the fast.
6. One should take as much rest as one can during the fast. Hard physical labor should be avoided during the time of the fast. Those whose nature of work is such that they have to do hard physical labor, they should observe only partial fast. Those who can observe silence during the fast should do so to save energy,
7. Long fasts of more than two days should be undertaken under the guidance and advice of an expert naturopath. It is however not essential to consult a doctor when one resorts to fasting to cure indigestion caused due to careless eating. In small ailments like headaches, stomach aches, bad cold, one may safely go in for a fast.
8. Fasting increases our will power. We should exert our will power fully on the day of the fast and should control our mind’s wanderings. The purification of the body and the mind achieved during fasting enables us to bring our mind to one-pointed ness and fix it in meditation. It is easy to meditate on the day of fasting because fasting makes the mind quiet, placid and thus easy to control.