A study from Australia found that middle-aged women who ate meat daily were significantly more likely to be diabetic and have uncontrolled high levels of blood sugar than those who ate a plant-based diet with little or no red meat (Nutrients, Oct 6, 2022;14(19):4152). The authors conclude that plant-based diets reduce diabetes risk by increasing the body’s response to insulin and reducing body fat.

I have reported often on the association of red meat with increased risk for heart attacks and certain cancers, but until recently there has been less evidence of association between eating red meat and developing diabetes.
• A review of three U.S. studies including more than 10,600 people, average age 54, found that those who ate a plant-based diet were far less likely to develop diabetes, be overweight, have high blood pressure, have high cholesterol, take blood pressure and cholesterol drugs, to be less active and have a family history of diabetes (Diabetologia, April 8, 2022;65:1119–1132).
• A review of 28 studies found that risk for type II diabetes was increased by 36 percent for every 100 grams of meat from mammals or 50 grams of processed meat eaten each day (Diabetes Metab, Oct 2020;46(5):345-352).
• A study that followed 63,257 Chinese adults, aged 45–74, for an average of 10.9 years found that eating red meat was associated with increased risk for developing diabetes (American Journal of Epidemiology, May 23, 2017) as did many other studies (JAMA Intern Med, Jul 22, 2013;173(14):1328-35; Nutrients, 2014 Feb; 6(2): 897–910; Am J Epidemiol,(2016) 183(8):715-728; Diabetes Spectrum, May 2017;30(2):82-88; Diabetes Care, 2004;27(9):2108-2115; Am J of Clin Nutr, 2004;79:70-750; Amer J Clin Nutr, 2011;94:1088-1096).

In these studies, red meat is defined as beef, pork, lamb, game and any other meat from mammals, while processed meats include all cured, salted, smoked or canned meats such as hot dogs, bacon, ham, sausages, corned beef and luncheon meats.

How Does Eating Meat Increase Diabetes Risk?
• Preservatives, additives and chemicals such as nitrites and nitrates that are added to the meat during processing can damage the pancreas and decrease insulin production (Clin Biochem, 2008;41:1454–1460).
• Many studies show that meat eaters are more likely to be overweight or obese, and excess body fat is a major risk factor for diabetes (Nutr Rev, 2006;64:175–188).
• Meat is high in fat (particularly saturated fat) and cholesterol that can increase fat deposition in the liver. Excess liver fat (fatty liver) can cause insulin resistance (Curr Diabetes Rev, 2006, 2, 367–373).
Restricting meat reduces visceral fat and improves insulin sensitivity, even more than a conventional diabetic diet (Diabet Med, 2011, 28, 549–559).
• Cooking meat at high temperatures or without water forms Advanced Glycation Endproducts (AGEs), chemicals that can increase diabetes risk (Diabetes Care, May, 2018;41(5):1049-1060).
• Non-diabetics gain increased insulin sensitivity after avoiding meat (Am J Med 2005;118:991–997).
• Meat contains highly-absorbable heme iron that can damage insulin-producing pancreatic cells (Biochem Biophys Acta, 2009;1790:671–681). High iron levels can cause insulin resistance, and reducing iron levels can increase insulin sensitivity (Br J Nutr, 2001;86:515–519).

The TMAO Theory on Meat and Diabetes
Eating meat daily is associated with higher blood levels of TMAO (PLoS One, Jan 15, 2020). Most cases of diabetes are caused by insulin resistance (not being able to respond to insulin), and after just four weeks on a high-meat diet, people were less able to respond to insulin (Metabolism, March 2017;68:173–183). Meat contains two chemicals called choline and lecithin that pass all the way to the last five feet of your intestinal tract (your colon), which contains more than 100 trillion bacteria (PLoS Biol, Aug 2016;14(8):e1002533). Some of these bacteria are healthful, but others are harmful because they convert choline and lecithin into a chemical called TriMethylAmine (TMA). The TMA is absorbed into your bloodstream and travels to your liver, which converts TMA to TriMethlAmineOxide or TMAO (N Engl J Med, Apr 25, 2013;368(17):1575–1584). A diet high in meat and other animal products can markedly increase the growth of these harmful colon bacteria that raise TMAO levels and reduce the growth of healthful bacteria that lower TMAO levels (Molecular Nutrition and Food Research, July 5, 2016).

High blood TMAO is associated with high blood sugar levels. Mice fed TMAO developed high blood sugar levels, high fasting insulin levels and signs of an overactive immune system called inflammation (J Bioscience and Bioengineering, 2014;118(4):476–81). The same associations have been found in humans (Am J Clin Nutr, 2017;106(3):888–94).

My Recommendations
For many years I have reported on reducing risk for heart attacks by limiting meat. Recent reports remind us that eating mammal meat is associated with increased risk for type II diabetes as well. High levels of TMAO are also associated with increased risk for strokes and some types of cancers. A high-plant diet that is low in mammal meat and other animal products will help to maintain a colony of healthful colon bacteria in your colon and also help to protect you from becoming diabetic.
More Vegetables, Less Diabetes
Lifestyle Changes to Prevent and Treat Diabetes
Treating Type II Diabetes and High Blood Pressure with Diet