It is the latest radical food fad backed by Gwyneth Paltrow – to cut out certain 'dangerous' vegetables.

The diet recommended on the actress's lifestyle blog Goop is now facing a backlash from nutrition experts.

Writing for Goop, Dr Steven Gundry warns that lectin, a protein in tomatoes, cucumbers, aubergines and whole grains, can cause weight gain, arthritis and dementia.

Gwyneth Paltrow, left, promotes clean living on her website, Goop. But the lifestyle blog has come under fire for claiming vegetables such as cucumbers, right, are 'dangerous' to health

Dr Gundry, who believes plants are sentient, says we should peel and de-seed vegetables, avoid quinoa and eat white bread instead of brown.

He insists lectin is the 'biggest danger in the Western diet'.

But Dr Megan Rossi, of King's College London, said: 'The health benefits associated with these foods far outweigh the negative effects of trace amounts of lectins for most people.'

Dr Frankie Phillips, of the British Dietetic Association, said: 'For most people, avoiding the foods that contain lectin is unnecessary – we are well-equipped physiologically to manage them.

'In fact, cutting out these foods could lead to a substantial decrease in dietary fibre intake.'

Mike Lean, of Glasgow University, added that the theory is 'taking a very specific issue which can be a problem, lectins in [raw] red kidney beans, and then assuming that all fruits and vegetables that contain lectins must be hazardous'.