A vegan diet with no added fats caused 117 obese people, average age 54, to lose 13 pounds over 16 weeks (JAMA Netw Open, Nov 30, 2020;3(11):e2025454). They decreased their risk of becoming diabetic by:
• increasing the rate that they burned calories by more than 14 percent, and
• reducing insulin resistance by taking more than 34 percent of the fat out of their livers and more than 10 percent of the fat out of their muscles. The most common cause of Type II diabetes in North America is excess fat stored in muscles and liver (Obes Res Clin Pract, 2014;8(4):e350-e355).

The study diet consisted of vegetables, grains, legumes, and fruits, with no animal products or added fats. Participants were given a vitamin B12 supplement. They attended weekly classes for detailed instruction and cooking demonstrations. For both the study group and the 106-person control group, alcoholic beverages were limited to one per day for women and two per day for men. All participants were asked to maintain their customary exercise habits and medications unless modified by their personal physicians.

How Getting Fat Out of Your Liver and Muscles Can Help to Prevent and Treat Diabetes
A healthful low-fat vegan diet will reduce the fat in the liver and muscles that increases risk for type II diabetes. When your blood sugar level rises, your pancreas releases insulin, which drives sugar from the bloodstream into the only two places that can store sugar: your liver and muscles. However, your liver and muscles can store only very limited amounts of sugar, so all of the extra sugar in the blood is rapidly converted to triglycerides. Then your good HDL cholesterol lowers blood triglyceride levels by carrying the triglycerides into your liver to cause a fatty liver. The major cause of type II diabetes is having excess fat in your liver (Hepatobiliary Surg Nutr, Apr 2015;4(2):101–108) and muscles (Amer J of Clin Nutr, April 2000;71(4):885–892). Excess fat in your liver and muscles prevents them from accepting sugar from the bloodstream, so people who have excess fat in their livers and muscles often have sustained high blood sugar levels which is diabetes.

Avoiding or Limiting Animal Products Can Also Help to Prevent and Treat Diabetes
• Eating meat causes a high rise in insulin because insulin’s main function is to drive sugar, fat and amino acids, the building blocks of protein, into your liver. Meat is full of protein and usually contains lots of fat. Protein has a minimal effect on blood sugar levels with adequate insulin. However, with insulin deficiency that occurs in type I and late type II diabetes, the liver rapidly converts protein and fat to sugar to cause a high rise in blood sugar (Diabetes Educ, Nov-Dec 1997;23(6):643-6, 648, 650-1). This is called gluconeogenesis. Eating lots of protein can also increase diabetes risk by adding fat to the liver, and harm people who are already diabetic by increasing the rate of gluconeogenesis.
• Many recent articles show that the choline and lecithin found in meat markedly increase the production of TMAO, which increases risk for obesity, diabetes and heart attacks (Obesity Reviews, Feb 3, 2020).
• Mammal meat contains a sugar-protein called Neu5Gc that can turn on your immune system to cause inflammation, which increases risk for obesity, heart attacks and strokes (Mol Aspects Med, Oct 2016;51:16–30).

More Support for a High-Plant Diet
• A review of the world’s literature shows that avoiding or limiting meat lowers risk for diabetes and heart attacks (J Geriatr Cardiol, May 2017;14(5):317–320).
• Obesity is uncommon in vegetarians (Diabetes Care, 2009;32(5):791-796).
• A high-plant diet is usually lower in calories (J Acad Nutr Diet, 2015;115(6):954-969), causes increased amounts of calories to be burned by your body after you eat them (Am J Med, 2005;118(9):991-997), and reduces the amount of fat that is stored in the liver and muscles (Obes Res Clin Pract, 2014;8(4):e350-e355).
• Plant-based diets have been shown to increase the number of calories a person burns at rest, called basal metabolism (Int J Obes Relat Metab Disord, 1999;23(12):1307-1313).
• A high-plant diet can lower high blood pressure (J of Hum Hypertension, July 5, 2016).
• A high-plant diet is associated with a markedly reduced risk for strokes (Stroke, Jun 2014;45(6):1613-9).

My Recommendations
I believe that we have strong evidence associating regular consumption of mammal meat or processed meats with increased risk for obesity, diabetes, heart attacks, strokes and some cancers. However, we have no proof that eating meat fewer than a couple of times a week is harmful. Whatever you decide about eating animal products, I recommend that you eat lots of foods from plants — vegetables, fruits, beans, whole grains, nuts and other seeds. See Anti-Inflammatory and Pro-Inflammatory Food