Many people take Upavasa in another sense. Just taking the satwik aahars on a particular day is not an Upavasa. They don’t know actually, why we need to do fasting? For it we have to first understand about our body and why it needs fasting. In the body’s natural cycle something called board (Mandal) which means that in every 40 to 48 days, the body goes through a particular cycle.