Sydney Roosters players have embarked on a full-day fast – a radical dietary move including activated charcoal, diatomaceous dirt and sea water to promote detoxification.

As revealed on Seven News, the entire Roosters squad performed the fast shortly after they returned to training last November. Players involved in the 2017 World Cup were not included.

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The fast was introduced by new dietary consultant Keegan Smith, son of former coach Brian. Keegan Smith previously worked with the Roosters in 2013 – the year of the club’s most recent premiership.

Players were told to begin the fast with tongue scraping and oil-pulling. The latter involves swilling either oil around the mouth for 20 minutes to whiten teeth and eliminate germs from the mouth.

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Instead of lunch, a relaxing stint in a float tank or sauna was recommended, followed by soluble substances known as ‘cleaners’. These included clay, diatomaceous dirt and activated charcoal – all of which are said to keep the gut healthy.

Later in the day players were asked to spend time outside – breathing and swimming. The recommended breathing technique was taken from famed Dutch ‘Iceman’ Wim Hof, who has developed the ability to withstand sub-freezing temperatures for long periods by regulating his breathing.

A dip in the ocean was also recommended – complete with two mouthfuls of sea water.

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7th Tackle understands the fast was part of Smith’s plan to boost the squad’s immunity. Teams across all codes are more frequently concentrating on diet to avoid annual slumps that see large numbers of players struck down with illness and fatigue.

However, the president of Sports Dieticians Australia, Simone Austin, told Seven News she did not believe in fasting as option to achieve that goal.

“I think the fact they are looking at nutrition as a positive way to improve sporting performance is fantastic but I believe that you need to use research based recommendations and evidence,” Austin told Seven News.