A well-known television doctor has warned that the popular 'juice detox' could have detrimental effects on your health.
The diet involves swapping three meals a day for shots of wheatgrass and curly kale -- and is a favourite of many Irish celebrities.
But Dr Christian Jessen, who is best known for appearing on popular UK TV show 'Embarrassing Bodies', says the lack of fibre can cause health problems.
"There is nothing wrong with having a fruit juice," he told the Irish Independent. "It's the 'juice only' diets I have problem with. They tend to take all the fibre out when you drink those juices."
While those who promote the detox say the diet of green juice can make your skin glow and waistline shrink, Dr Jessen says the juices are often loaded with sugar.
"They're very, very high in sugar and not a lot else. You tend to see people who go on long-term juice diets for seven days or longer start to suffer from skin problems, hair problems and nail problems.
"Ironically they start to suffer from mineral deficiencies. I would always say balance is best -- never go for these extremes. If it's got the words detox or cleanse in it avoid it," he said.
TV presenters Laura Whitmore and Amanda Byram, actress Amy Huberman and model Aoife Cogan are among the celebrities to have tried 'juicing'.
And Elaine Connolly (33), who runs Juice Delivery Dublin, says the doctor has got it all wrong.
"I couldn't disagree more strongly with what Dr Jessen has said," she said.
"I used to suffer from very brittle nails and fine hair but since I started juicing my hair, skin and nails have all improved.
"I now juice every four to five weeks and always feel better for it."
Dr Jessen is best known for TV shows 'Embarrassing Bodies' and 'Supersize Vs Superskinny'.
The latter encourages an obese individual to swap eating habits with an individual suffering from an eating disorder such as anorexia nervosa.
The programme has been criticised for sensationalism but Dr Jessen says that is part of its strength.
"When the superskinny person sits there with a mound of food in front of them and says 'This is ridiculous' they essentially do my job for me. They tell our overweight patient they are eating too much. It's extremely psychologically effective.
"I think the underweight are really ignored in the TV landscape -- they slip under the net. And I think the show is good at raising awareness of these illnesses."
Dr Jessen was speaking at the launch of www.takecontrol.ie, a public awareness campaign aiming to break down one of the remaining sexual taboos -- premature ejaculation.