It is believed that by observing a fast on Vaikuntha Ekadasi day and spending the day in poojas and prayers to Lord Vishnu, one will be absolved of all sins and will attain Moksha and the doors of Vaikunta will be kept open for the soul after it leaves this physical body.
Just as impure gold is rendered pure by melting it in the crucible again and again, so also this impure mind is rendered purer by repeated fasting. If you cannot fast for the full twenty-four hours, at least fast for 10-12 hours and then take some milk and fruit. Occasionally, a complete fast is greatly desirable for all to keep up good health, to give adequate rest to the internal organs and maintain celibacy. In the Gita you will find: “Verily, Yoga is not for him who eats too much, nor who abstains to excess, nor who sleeps too much, nor to the excessively wakeful”.