There are spiritual as well as physical benefits from this ancient practice.
The eleventh day in the two lunar cycles of every month – the two fortnights known as Sukla paksha (waxing moon) and Krishna paksha (waning moon) – is considered important in our traditions.
Known as Ekadasi, the eleventh day is considered an auspicious day for spiritual practices. Eka in Sanskrit is one, and dasa means ten.
Eleven is the most spiritual number. In astrology and numerology, it is called a 'master vibration number'. The celebrated Vedic hymn Sri Rudram praises the creator through eleven chapters, or anuvakas. Spiritually, Ekadasi symbolises our eleven senses – five sense organs, five action organs and the mind.
Countless people observe fast on the day, known as Ekadasi Vrata, and abstain from food or even water, or by consuming just phala ahar – milk, juices and nuts, depending on their willpower and strength of their body. The importance of the eleventh day in the fortnightly lunar cycle has been extensively commented in our scriptures. Vedic astronomy shows the significance of the moon's position and its influence over the human mind.
Our bodily functions are majorly influenced by the moon and its magnetic pull. The moon affects the water element in the creation. We see how high tides in the sea are markedly higher during full moon nights. More than sixty percent of the human body is made up of water, showing the moon's influence on the body and mind.
Our ancestors have proved that the toxins in our body get aggravated as we move towards the full moon or new moon. When the stomach is kept light or empty, it helps to detoxify the body, cleanse the blood, and improve the functioning of kidneys and liver. Fasting on Ekadasi thus helps to cleanse the body in the natural way, and direct the awareness inward. It is the practice to eschew consuming rice or starchy items on Ekadasi day for the reason that rice grains hold a lot of water content. Since the moon attracts water, eating rice can cause unsteadiness of the mind.
Ekadasi is considered an auspicious day for the worship of Lord Vishnu, the protector and nourisher of living beings. Padma Purana and other texts describe the origin of Ekadasi worship linking to Vishnu's killing of an asura on the day through his yoga maya. Ekadasi is also known as upavasa, or a day to come closer to God. Another meaning of upavasa is kindling the sacred fire (within).
Thus, the purpose of Ekadasi is not merely to starve the body, but to bring our mind and heart closer to the Lord. Mahatma Gandhi, who used to go on regular fasts, had said that if physical fasting is not accompanied by mental fasting, “it is bound to end in hypocrisy, since the strength of the soul grows in proportion as you subdue the flesh”.
The Vedas prescribe many methods of atonement, or prayaschitta, to break free of past bad karma. Among them, fasting on Ekadasi is considered effective, and as a powerful means to feel the presence of the divine within. Therefore, as a spiritual tool or a wellness initiative as part of intermittent fasting, Ekadasi vrata has tremendous value and relevance.