Media reports indicate that two leading French dieticians are set to fight out a libel suit in court Tuesday for the title of most celebrated slimming guru in the world.
At loggerheads is Dr Pierre Dukan - inventor of a diet which has swept Europe and America and been adopted by celebrities from Jennifer Lopez to Katherine Jenkins and Gisele Bundchen - and Jean-Michel Cohen, who has hundreds of thousands of followers in France.
Cohen says that Dr Dukan's diet is a dangerous re-hashing of old ideas, which can increase cholesterol and generate heart problems and breast cancer, reports the Independent.
He instead favours a calorie-based diet in which slimmers eat a limited amount of most things (even chocolate) so long as they exercise regularly as opposed to Dr Dukan's protein-based diet, which dismisses calorie counting and allows slimmers to eat as much as they like of a limited number of things.
At the heart of the case is an interview given by Dr Cohen to a French health magazine last year. Asked who benefited from the Dukan Diet, Dr Cohen said: "The slimming industry, doctors, pill salesmen, publishers, newspapers... Everyone who has climbed on to the bandwagon of this fantasy."
Dr Dukan is suing Dr Cohen for libel. He claims a modest 15,000 euros (13,000 pounds) in damages.
Interestingly, tens of millions of euros in book royalties and profits from spin-offs could be at stake as both men are best sellers. Dr Dukan, though, is far more successful. Three of his books were in the top ten French best sellers last year.
Meanwhile, Dr Cohen's lawyer, Richard Malka, says allegations of libel are "ridiculous and abusive". The medical community, he claims, is "unanimous in believing that the Dukan diet carries grave risks... How can it be defamatory to say that diet programmes bring profits to those who publish them?"