Ekadashi is a Sanskrit word for number 11

In the Vedic lunar calendar the 11th day of each half of the month is entitled as Ekadashi also known as Hari Vasara since this day is devoted to Lord Vishnu. Each Month has two Ekadashi days on the Vedic calendar. It is the most significant day chosen for prayers and fasting for all Hindus. It is believed that a person who observes the fast on this day becomes free from all earthly influences. It helps one to manage to get the peace of mind to become one with Ishvara and attain moksha.
The importance of Ekadashi Vrat has been listed both in Padma Purana and Skanda Purana. Ekadashi is a bimonthly occasion observed by all Vishnu devotees who rigorously restrain themselves from having grains, beans, cereals, and certain vegetables and spices. All preparation starts from the Dasami day that is a day before Ekadashi. Early morning on Dasami devotees take a ritual bath followed by all other daily routines required to deliver the puja or prayers and take up just a single meal and avoid salt completely. The next day being the Ekadashi which is meant for complete fasting .

Scientific Importance of observing a fast on Ekadashi

Based on recent research it is said that the air pressure on earth changes drastically on both the new moon (Amavasya) and the full moon (Poornima) days. Due to the increase in the atmospheric pressure in the ocean on Amavasya the waves are very high and rough but the next day onwards waves are calm. Atmospheric pressure is said to be the lowest on Ekadashi day hence it is the best time for fasting and body cleansing.

Health Benefits

Fasting on Ekadashi is also for many health benefits: fasting detoxifies our body. It also encourages in concentrating on meditation along with prayers. Everyone wants to look good and younger now a days so Ekadashi fast is a best method for the same.

1- Cleanse bowel system

Observing Ekadashi fast gifts you with a healthier body, clean bowel system which sets you free from regular aliment at the same time providing mental peace and self realization.

2- Body Treat

Ekadashi fast offers better blood flow or circulation and enhances bodies capability to get rid of toxins. Improves Immunity against all diseases and slowing down the aging process leaves us more energetic and brisk.

3- Improved way of life

A single day of fasting teaches us: self control, discipline and free us from depression also helps us break those addictions that destroys our mind body and soul acquiring new and positive way of life.