A report commissioned by the World Health Organization (Who) has found that a high-fibre diet can cut the risk of heart disease and increase the chances of avoiding related illnesses such as diabetes.

The study, which will make for difficult reading for food manufacturers making low-carb products, said that fibre in ‘good’ carbohydrates such as wholegrain bread, cereal, pasta and oats has a protective effect.

It said that eating more fibre will cut people’s chances of heart disease and early death.

But the findings are incompatible with fashionable low-carb diets.

The research was led by Prof Jim Mann’s team at the University of Otago in New Zealand.

Mann told the UK’s The Guardian newspaper that the research “does contribute to the debate considerably”.

He added: “Here we have got very strong evidence that a high-fibre diet, which for the majority of people is at least high-ish in carbohydrates, has an enormous protective effect – a wide range of diseases including diabetes, cardiovascular disease and cancer benefit from a high-carbohydrate diet.”

The review found that people should be eating at least 25g to 29g of fibre a day, with indications that over 30g is even better. Most people in the world manage less than 20g.

Among those who ate the most fibre, the analysis found a 15-30% reduction in deaths from all causes, as well as those related to the heart, compared with those eating the least fibre.

Coronary heart disease, stroke, type 2 diabetes and colorectal cancer were reduced by 16-24%.