An increasing number of Britons are excluding key foods from their diet because of fears of allergies and intolerances, GPs warned yesterday. Research involving 250 GPs suggested celebrity food fads were to blame for many people self-diagnosing these problems.

But doctors warned that cutting out important foods without medical advice could do more harm than good.

Norwich Union Healthcare's Health of the Nation Index found 63% of GPs reported an increase in patients reporting a food intolerance in the last year. But 73% believed their patients' reactions were psychological and not physical.