One of the 5 niyams in ashthang yog is ‘tapa’, that is, to heat the body by giving it pain. It is a basic purification, a means to cancel out your negative karmas and aid evolution. Fasting is one way of putting yourself through pain.
During navratras fasts are observed for purification as well, both etheric as well as physical.
The nine nights and ten days of navratras hold within them the energy of ten forms of shakti – shailaputri, brahmcharini, chandrakanta, kushmanda, skandmata, katyayani, kaalratri, mahagauri, siddhidatri and aparajitha thus eachnavratra has a specific purpose.
In the navratras weather changes, ie, various energies of this creation move from imbalance towards a new normalcy. We are a poorna ansh of this creation, in these 9 days we too move towards a new normalcy, the prana shakti inside our body undergoes a process of re-alignment, for this re- aligning the body has to be kept light.
Apart from fasting, there are certain mantras also which are chanted on these days for a complete body detox.
For 9 days you re-align the body and after that on the 10th day accept new energies.
The Guru knows the capacity of a shishya and prescribes a fast and mantra sadhna depending upon his/her requirements. Unsupervised fasting or starving the body to lose weight has an opposite effect taking one towards imbalance. Any sadhna or fast would bear results only when carried out with a sense of detachment, therefore it is important to first bring that detachment in oneself through correct practice of Ashtang Yog and Sanatan Kriya.
