Data from nine studies of 307,099 middle-aged people followed for up to 28 years shows that those who ate lots of plant-based foods and restricted meat had a 23 percent lower risk of developing type 2 diabetes, and those who ate the most vegetables had a 30 percent lower risk of developing diabetes than those who ate the least vegetables, no matter how much they weighed (JAMA Intern Med, published online July 22, 2019). The group that ate the most plants still ate 1.7 to 3.9 servings/day of dairy, eggs, fish, or meat. Mediterranean diets, the DASH diet (Dietary Approaches to Stop Hypertension), and the Alternate Healthy Eating Index all allow small amounts of meat and produce similar health benefits.
Eating lots of plants helps to prevent and treat diabetes because plants have lots of soluble fiber that is not absorbed until it reaches your colon. There bacteria break down soluble fiber into short chain fatty acids (SCFAs), which are absorbed into your bloodstream and travel to your liver where they help to make your cells more sensitive to insulin; lower high blood sugar, blood cholesterol and blood pressure; and reduce inflammation. Plants also help to prevent obesity by improving leptin, adiponectin, high sensitivity C-reactive protein, and interleukin-6 blood levels.
Meat and Risk for Diabetes
Most people know that a diet with a lot of added sugar increases risk for diabetes, but a diet that includes regular portions of red meat also increases risk for diabetes, and if you already have diabetes, eating meat can drive blood sugar levels even higher. Eating meat causes blood sugar and insulin levels to rise (Diabetes Res Clin Pract, Aug 2011;93 Suppl 1:S52-9). Insulin drives sugar into cells, and it also drives the building blocks of protein (amino acids) into cells (Biochem J, Nov 1958;70(3):353-358).
Eating red meat or processed meat is also associated with excess fat in the liver that causes high blood sugar levels, which can lead to diabetes (Journal of Hepatology, March 19, 2018). The authors of this study believe that the most damaging component is heterocyclic amines (HCAs) that are formed when the meat is cooked at high temperatures. A review of three prospective studies showed that the highest association of diabetes with red meat, chicken or fish came when they were cooked at high temperatures without water — grilling, broiling or roasting (Diabetes Care, March 14, 2018). When you cook with water, the sugar in foods combines with water to form harmless byproducts, but cooking without water allows the sugar in meats to combine with proteins and DNA to form HCAs, which increase heart attack and cancer risks as well as risk for diabetes.
My Recommendations for Preventing and Treating Diabetes
• Eat a wide variety of vegetables, fruit, beans, nuts, whole grains (not ground into flour) and other seeds
• Restrict sugar-added foods
• Restrict all drinks with sugar in them, including fruit juices
• Restrict red meat and processed meat
• Avoid being overweight, particularly if you store excess fat in your belly
• Try to exercise for at least 30 minutes every day