James Martin reckons margarine should be banned after slamming the butter alternative as "dreadful stuff".
The celebrity chef, 50, wrote a book about the virtues of butter in 2021, citing the advantages of growing up on 'full fat milk and cream'.
While butter is made from cream or milk, margarine uses a blend of oils without any saturated fats - but James thinks it's "horrendous".
Claiming people are not aware of the 'plastic-like' food product's 'hidden fats', he said: "Margarine should be banned. It's dreadful, dreadful stuff, it's two elements away from plastic, it's horrendous stuff.
"It's the ready-made food, it's the packet food, the hidden salt, hidden fat. That's the problem in this country.
"It's not the butter in a butter block or butter you put on your toast. It's the fact that not as many people cook in the UK as they do in France or Italy or Spain," reports The Sunday Post.
James hosted BBC 's Saturday Kitchen 2006 for 10 years on BBC One before making his shock move to ITV in 2016, bagging his own show a year later on the channel.
He has been hosting Saturday Morning since 2017 and celebrated its 200th episode in May 2022.
Earlier this year, James had viewers in tears when he told seasoned chef Brian Turner he loved him.
During a segment on the popular programme, the 76-year-old opened up about how he had a stroke in June 2022.
James referred to Brian as his "TV dad", before the culinary veteran revealed details his health.
The Ready Steady Cook star explained: "I had a stroke in June last year and the people at the London hospital were fantastic and helpful."
Brian added: "So excuse me if I make a stammer occasionally, but we will catch up at the end."
James responded: "It's OK, it's OK. I love you fella. So a round of applause for everyone who's been looking after you. It's a pleasure to have you back. You're welcome anytime."
Viewers of the ITV show were happy to see the pair back reunited as they took to Twitter to talk about the emotional reunion.
One wrote: "So so lovely to see Brian back with his TV son. Those man hugs made me tear up! All the best to you Chef Turner."
While another said: "I'm watching with tears in my eyes. Warmed to my heart to see how James is so caring to him."