A new study from the Harvard T.H. Chan School of Public Health found that a healthy plant-based diet significantly lowers the risk of type 2 diabetes.

Study authors commented that “existing studies suggest a lower incidence of type 2 diabetes in people reporting a diet rich in fruit, vegetables and whole grains, and a higher incidence in those reporting consumption of red and processed meat,” but they wanted to go further by providing more clarification and detail on the types of foods associated with the risk of type 2 diabetes.

The study, published online in the journal PLOS Medicine and funded by the U.S. National Institutes of Health, surveyed 200,000 health professionals for more than 20 years.

Researchers used a diet index in which plant foods received positive scores and animal foods and less healthy plant foods (sweet beverages, refined grains) received reverse scores.

Study Results

Overall, a healthy plant-rich diet that was low in animals foods was associated with a 20 percent reduced risk of type 2 diabetes.

The most healthy plant-based diet (centered around whole grains, fruits, vegetables, legumes, and nuts) was associated with a 34 percent reduced risk of type 2 diabetes.

A less-healthy plant-based diet (more refined and processed foods and sugary drinks) was associated with a 16 percent increased risk of type 2 diabetes.

Even a modest reduction in animal-based foods (from 5-6 servings to 4 servings per day) was associated with a lower risk of type 2 diabetes.

“This study highlights that even moderate dietary changes in the direction of a healthful plant-based diet can play a significant role in the prevention of type 2 diabetes,” said lead study author Ambika Satija, a postdoctoral fellow in the Department of Nutrition.

Conclusions

Senior study author Professor Frank Hu, professor of nutrition and epidemiology at the Harvard Chan School said: “A shift to a dietary pattern higher in healthful plant based foods such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in animal based foods, especially red and processed meats, can confer substantial health benefits in reducing risk of type 2 diabetes.”

As to how a healthy plant-based diet could lower the risk of type 2 diabetes, study authors noted that such a diet would be rich with beneficial dietary fiber, antioxidants, and micronutrients, and low in saturated fat.