Today, there are at least 360 million people in the world with diabetes and their ranks are expected to expand to 550 million in the next 15 years. Many people are born with a genetic predisposition to the disease but others will acquire it as a consequence of unhealthy lifestyle choices. Either way, diabetes can often be avoided, delayed, or reversed by consuming a diet high in fiber.

High-Fiber Diets Are Plant-Based

All plants contain fiber so a plant-based diet is a high-fiber diet. Animal foods — meats, eggs, and dairy — contain no fiber. Processed foods such as cereals, snacks like crackers, bread, pastries, and other baked goods made from refined (enriched) flours have little or no dietary fiber in them; the extensive factory processing they endure strips almost all the fiber out of them.

Dietary fiber comes in two forms and plant foods usually have a combination of the two:

  • Soluble fiber — This form dissolves in water (soluble) and is abundant in oats, barley, beans, peas, carrots, citrus fruits, and apples. Soluble fiber helps maintain healthy glucose and cholesterol levels.
  • Insoluble fiber — This form does not dissolve in water but passes instead mostly intact through the digestive tract, aiding in digestion and eliminating excess cholesterol and other harmful elements as it goes. Insoluble fiber is important for good bowel health; it eases constipation and many other irregularities of the bowel. Whole grains, whole grain flours, wheat bran, nuts, and beans are excellent sources of insoluble fiber. Potatoes, green beans, and cauliflower are good vegetable choices.

All fiber helps maintain a healthy weight by creating the feeling of fullness so overeating is minimized. It slows digestion so the feeling of fullness lasts longer, prevents dangerous spikes of insulin and glucose, and nutrients can be thoroughly broken down and fully absorbed into the bloodstream.

Diabetes and Diet Around the World

Most of the research done on the effects of a high-fiber diet and type 2 diabetes have been conducted in the United States using the typical American diet, which is comparatively low in dietary fiber. Dietary fiber intake varies substantially between the US and Europe, where fiber intake is high, so researchers at the Norwegian University of Science and Technology and Imperial College London collaborated on a large-scale study that evaluated the high-fiber effect on diabetes in eight European nations plus a meta-analysis of similar studies in 18 other nations around the globe.

Study of Eight European Nations

The researchers followed 11,559 diabetic study participants for 10.8 years. This study group was matched with 15,258 people who did not have type 2 diabetes at the beginning of the study period. They, too, were followed for almost 11 years.

All study participants were divided into four groups of an equal number according to their normal intake of dietary fiber. The researchers discovered:

  • The group consuming the most fiber enjoyed an 18% reduced risk of developing diabetes when compared to those with the lowest dietary fiber intake.
  • Those who consumed a diet high in fiber from whole-grain cereals enjoyed a 19% reduced risk of diabetes.
  • Those getting most of their fiber from vegetables saw a 16% reduced risk.
  • Fiber from fruits did not alter the risk of diabetes.

The only factor that canceled out the diabetes-preventing effect of a high-fiber diet occurred in individuals who measured in the obese range of the body mass index (BMI). The risk of diabetes could not be reduced by a high-fiber diet when obesity exists.

Meta-Analysis of 18 Global Nations

This study involved the evaluation of other studies from around the world:

  • 8 from the US
  • 4 from Europe
  • 3 from Australia
  • 3 from Asia

The combined studies involved more than 41,000 people recently diagnosed with type 2 diabetes. The research revealed:

  • For every 10 grams of fiber from any source consumed on a daily basis, the risk of diabetes dropped by 9%.
  • The risk of diabetes was reduced by 25% for every 10 grams of fiber per day that came from a cereal source.

The research contributes to the ever-growing body of evidence that documents the benefits of a high-fiber diet. Professor Nick Wareham, a senior author of the paper describing the combined studies, said, “Public health measures globally to increase fiber consumption are therefore likely to play an important part in halting the epidemics of obesity and of type 2 diabetes.”


  1. Wareham, Nick, et al. "Dietary fiber and incidence of type 2 diabetes in eight European countries: the EPIC-InterAct Study and a meta-analysis of prospective studies." Diabetologia (2015). Web. 10 June 2015.
  2. "Dietary Fiber." MedlinePlus. US National Library of Medicine, 28 May 2015. Web. 10 June 2015.
  3. "Nutrition and healthy eating." Mayo Clinic. Mayo Foundation for Medical Education and Research, 17 2012. Web. 10 June 2015.