Eating a vegan or vegetarian diet can reduce the risk of developing diabetes by almost a quarter, according to new research.
An analysis of more than 300,000 people found those whose diets were mainly plant based were 23 percent less prone to the Type 2 form linked to obesity.
The foods are rich in antioxidants that protect against the potentially fatal disease, say scientists.
They improve sensitivity to insulin – the hormone that controls blood sugar – and reduce weight gain. They also combat inflammation, explained the US team.
The study is the first of its kind because it also differentiated between healthy and less healthy plant based foods.
The former included fruits, vegetables, whole grains, nuts, and legumes and the latter potatoes, white flour, sugar and modest amounts of animal products.
It also found the association was strengthened for those who ate diets emphasising healthy plant-based foods and lower consumption of unhealthy ones.
Senior author Professor Qi Sun, a nutritionist at the Harvard T.H. Chan School of Public Health, Boston, said: “Overall, these data highlighted the importance of adhering to plant-based diets to achieve or maintain good health.
“People should choose fresh fruits and vegetables, whole grains, tofu, and other healthy plant foods as the cornerstone of such diets.”
He added: “Higher adherence to plant-based eating habits was associated with lower risk of type 2 diabetes, especially when only healthy plant-based foods, such as fruits, vegetables, whole grains, legumes and nuts, were included in the definition of plant-based.”
The findings published in JAMA Internal Medicine add to evidence that diet is crucial in tackling a condition that now affects around four million people in the UK.
The vast majority, around nine in ten, suffer from Type 2 that can be avoided by making lifestyle changes.
Earlier studies have suggested plant-based diets may help lower type 2 diabetes risk.
But there has been a lack of research analysing the overall body of epidemiological evidence.
According to the researchers, their findings provide the most comprehensive to date supporting the link.
They pooled data from nine previous studies involving a total of from 307,099 participants with 23,544 cases of type 2 diabetes.
An estimated 549,000 people have Type 2 diabetes but are not aware of it.
Diabetes UK says a diet high in antioxidant-rich foods, such as fresh fruit and vegetables, is linked to a lower risk of Type 2 diabetes.
As well as fresh fruit and vegetables, there are other foods, such as wholegrains, nuts, seeds, legumes and fermented foods like yoghurt, that are protective against Type 2 diabetes.
Ultimately, the best way to reduce your risk of Type 2 diabetes is by maintaining a healthy weight through a balanced diet and regular exercise, says the charity.