Footy great Jimmy Bartel explains why he went on a diet so extreme he is not eating any food for THREE DAYS

Jimmy Bartel has been observing a 72-hour water fast, with the footy doing a great job of explaining why he's following the extreme diet.

Water fasting is the practice of not eating food and drinking only water for a specified period of time, usually between 24 and 72 hours.

Experts say water fasting may provide several health benefits, including promoting autophagy (the process of breaking down cells), lowering blood pressure and reducing the risk of chronic disease.

“So you just have water for 72 hours,” Bartel explained on 3AW Melbourne.

“It's about getting into ketosis and things like that. Cleanses all your cells and stuff like that.

Jimmy Bartel has revealed why he observes a 72-hour water fast

The Geelong great says he follows the extreme diet for its various health benefits

“It was for health reasons.”

Geelong hero Bartel ends his fast at 7am on Thursday, with the football legend tempted to break his fast with a sausage roll, cheese or a steak sandwich.

Medical advice is recommended before people follow a water diet, given the health risks associated with extreme diets.

Earlier this year, Bartel became a father for the third time after welcoming his first daughter into the world with girlfriend Amelia Shepperd.

The AFL star, 39, who shares two boys with ex-wife Nadia Bartel, announced the birth of his daughter Paloma Lucie in April.

In a heartwarming Instagram post, the footy player shared a black and white photo of his new bundle of joy holding his hand.