A diet rich in fibre found in bread, pasta, wholegrain cereals and potatoes could cut the risk of early death by up to a third, a study suggests.
The review commissioned by the World Health Organisation showed there was clear evidence people should increase their intake of fibre - which is found in high-carb foods - to reduce the risk of heart disease, stroke, diabetes and other chronic diseases.
It has reignited confusion - and debate - on carbohydrates, which in the weight loss world are considered "bad".
According to the study's authors, it is the type, quality and quantity of carbohydrates in people's diets that is important.
"Our research indicates we should have at least 25g to 29g of fibre from foods daily, although most of us currently consume less than 20g of fibre daily," said Dr Andrew Reynolds, lead author of the study.
"Our findings provide convincing evidence for nutrition guidelines to focus on increasing dietary fibre and on replacing refined grains with whole grains. This reduces incidence risk and mortality from a broad range of important diseases," said Professor Jim Mann, who co-led the research.
The team from the University of Otago in New Zealand looked at 185 clinical trials and 58 studies carried out during the last four decades involving more than a million people.
Their analysis found up to a 30% reduction in deaths from all causes among those who consumed the most fibre.
A high-fibre diet also showed up to a 24% fall in rates of colorectal cancer, type 2 diabetes, coronary heart disease and stroke.
For every 1,000 participants in the 243 studies and trials, the impact of consuming higher fibre intakes translates into 13 fewer deaths and six fewer cases of coronary heart disease when compared to those consuming lower fibre diets.
UK nutrition guidelines since 2015 recommend a daily fibre intake of 30g, but only 9% of adults manage to reach this target.
Professor Mann said the health benefits of dietary fibre - contained in foods such as whole grains, pulses, vegetables and fruit - come from its chemistry, physical properties, physiology and its effects on metabolism.
"Fibre-rich whole foods that require chewing and retain much of their structure in the gut increase satiety and help weight control," he said.