Ruby Tandoh launched a bitter attack on healthy eating gurus the Hemsley sisters as she denounced them for supporting a "dangerous" diet regime.
Ruby, who rose to fame with his sugary creations on Great British Bake Off, slammed the duo for endorsing the GAPS (Gut And Psychology Syndrome) diet which claims to cure everything from autism to schizophrenia and cancer through eliminating food groups and fasting.
The Hemsley sisters - Jasmine, 36, and Melissa, 30 - have shot to fame with their cookbook The Art Of Eating Well, and recently opened a cafe in Selfridges in London.
They even have their own cookery show, Eating Well with Hemsley + Hemsley, starting on Monday on Channel 4, showcasing recipes without gluten, grains or refined sugar.
But Ruby said the diet they supported made her "feel sick", calling it "quackery", "bad science" and saying it gave "false hope" to "vulnerable families, chronically ill people, cancer survivors, mentally ill people".
Ruby claimed that the Hemsleys' "wellness" approach contributes towards "food fear, fat phobia, classism" and the misdiagnosis of food intolerances.
But she acknowledged that food elimination diets do have benefits for those with conditions like epilepsy and diabetes.
Ruby instead urged her followers to "be mindful of pseudo-science" and follow a healthy approach to eating, urging: "Eat plenty & take care of yourself."
"Your health is too precious to lose to fad, conjecture & bad science," she wrote.
Noting how unpopular her opinion may be, she also jokingly tweeted: "I will not stop until I am blacklisted from every food industry event."
She even accused Melissa of being "untrustworthy" for saying her favourite food was bone broth, which has been touted as a new "superfood".
A spokesman for Jasmine and Melissa said: "The Hemsleys read widely around the topic of diet and health but are not advocates of anyone else's diet or regime.
"Their philosophy which they have developed over many years is quite simple: a healthy gut and good digestion helps lead to a healthy body and it is based on good food which you can enjoy every day."
Ruby followed up her rant with her own food-positive attitude.