Michael McIntyre has revealed he was left feeling "starved and depressed" after spending just under a week at the Mayr wellness resort in Austria back in February 2017.
The 44-year-old comedian admitted that he and his friend Paul Tonkinson were given just soup and crackers to eat and were even asked to drink Epsom Salts to shed the pounds.
The father-of-two spoke about the £2k-per-week retreat during a chat on the Table Manners podcast.
"You drink the Epsom salts first thing and then within 20 minutes, the whole of the clinic – which is full of wealthy fat people – are all rushing to the lavatory," he explained.
Michael went on to say he felt "hollow" afterwards and claimed that Paul – who lost 20lbs - "nearly died" during a woodland hike at the resort.
Michael made the decision to leave after six days, and upon hearing this Paul "burst into tears, he was so grateful”.
"I had enough," Michael admitted. "I lost a stone – we were only there six days. I was so emotional, depressed and confused and Paul was skeletal."
Michael's anecdote comes after he recently admitted that he regrets telling a particular joke about his wife Kitty in one of his stand up routines.
"I regret the jokes I made about her on a previous DVD about her farting in the night while she's asleep, because that's not actually, strictly true," he said during a recent interview.
"I regretted those, but she was fine with those. I ran them by her, she was fine. I think it upsets her a little bit when strangers come over and go, 'Oh, are you the one that farts in the night?' Or, 'Are you the one who can't pull her tights up?'
"I don't think she likes that. But ultimately, I need laughs to pay the bills and she's okay with it," he added.