Flashback Friday: The Best Diet for Diabetes

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

There are all sorts of different scoring systems to rate diet quality. My favorite, for its simplicity, is the “dietary phytochemical index”: a fancy name for a simple concept. It’s just the percentage of your calories from whole plant foods, so, 0 to 100. The average American diet has a score of 12. Twelve out of a hundred; so, like on a scale of one to ten, our diet is a one.

You can split people up based on how they score, and show how the higher you score, the better your metabolic markers when it comes to diabetes risk. There appears to be like this stepwise drop in insulin resistance and insulin-producing beta-cell dysfunction as you eat more and more plant-based. And that highest group was only scoring about 30—less than a third of their diet was whole plant foods, but better than the lowest, which was down around the standard American diet.

No wonder diets centered around plants, emphasizing legumes—beans, split peas, chickpeas, and lentils—whole grains, vegetables, fruits, nuts, and seeds, and discouraging “most or all animal products…are especially potent in preventing type 2 diabetes,” and as a little bonus, “have been associated with much lower rates of obesity, hypertension, hyperlipidemia, cardiovascular mortality, and cancer.” And not just preventing type 2 diabetes, but treating it as well. A systematic review and meta-analysis found that the “[c]onsumption of vegetarian diets is associated with improved [blood sugar] control.” But, how much improved?

Here’s one of the latest trials. The effect of a strictly plant-based diet centered around brown rice—it was done in Asia—versus the conventional diabetic diet on blood sugar control of patients with type 2 diabetes: a 12-week randomized clinical trial. For the diabetic control diet, they set up food exchanges, and calculated specific calorie and portion controls, whereas on the plant-based diet, people could eat much as they want—that’s one of the benefits. The emphasis is on food quality rather than quantity, and they still actually lost more weight. But, even after controlling for the greater abdominal fat loss in the plant-based group, they still won out. Of course, it only works if you actually do it, but those that pretty much stuck to the healthier diet dropped their A1c levels 0.9 percent, which is what you get taking the leading diabetes drug—but, of course, only with good side effects.

Yeah, but would it work in an underserved population? The impact of a plant-based diet support program on mitigating type 2 diabetes in San Bernardino, the poorest city of its size in California. A randomized controlled trial, but not of a plant-based diet itself as the title suggests, but of just an education program telling people about the benefits of a plant-based diet for diabetes. And then, it was up to them, and… still got a significant improvement in blood sugar control. Here are the numbers. Got a little better in the control group, but way better in the plant-based instruction and support group.

And, more plant-based diets are not just effective in the prevention and management of diabetes, but also its complications. Check this out. One of the most devastating complications of diabetes is kidney failure. This shows the decline in kidney function in eight diabetics in the one or two years before switching their diets. They all showed this steady, inexorable decline on a fast track, to complete kidney failure and dialysis. But then… they switched to a special supplemented vegan diet, and their kidney decline was stopped in its tracks. Imagine if they had switched a year or two earlier!

Most diabetics don’t actually end up on dialysis, though, because they die first. “Cardiovascular disease is the major cause of premature mortality” among diabetics; that’s why plant-based diets are perfect. “There is a general [scientific] consensus that the elements of a whole-foods plant-based diet—legumes, whole grains, fruits, vegetables, and nuts, with limited or no intake of [processed] foods and animal products—are highly beneficial for preventing and treating type 2 diabetes. Equally important, plant-based diets address the bigger picture…by simultaneously treating cardiovascular disease [our #1 killer]” along with obesity, high blood pressure, lowering inflammation. And, we can throw cancer in the mix too—our #2 killer. The bottom line is that “the case for using a plant-based diet to reduce the burden of diabetes and improve overall health has never been stronger.”

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• Pawlak R. Vegetarian Diets in the Prevention and Management of Diabetes and Its Complications. Diabetes Spectr. 2017;30(2):82-88.
• McMacken M, Shah S. A plant-based diet for the prevention and treatment of type 2 diabetes. J Geriatr Cardiol. 2017;14(5):342-354.
• Yokoyama Y, Barnard ND, Levin SM, Watanabe M. Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis. Cardiovasc Diagn Ther. 2014;4(5):373-382.
• Lee YM, Kim SA, Lee IK, et al. Effect of a Brown Rice Based Vegan Diet and Conventional Diabetic Diet on Glycemic Control of Patients with Type 2 Diabetes: A 12-Week Randomized Clinical Trial. PLoS ONE. 2016;11(6):e0155918.
• Ramal E, Champlin A, Bahjri K. Impact of a Plant-Based Diet and Support on Mitigating Type 2 Diabetes Mellitus in Latinos Living in Medically Underserved Areas. Am J Health Promot. 2018;32(3):753-762.
• Schwingshackl L, Hoffmann G. Diet quality as assessed by the Healthy Eating Index, the Alternate Healthy Eating Index, the Dietary Approaches to Stop Hypertension score, and health outcomes: a systematic review and meta-analysis of cohort studies. J Acad Nutr Diet. 2015;115(5):780-800.e5.
• Johansen K. Efficacy of metformin in the treatment of NIDDM. Meta-analysis. Diabetes Care. 1999;22(1):33-37.
• Bahadoran Z, Mirmiran P, Tohidi M, Azizi F. Dietary phytochemical index and the risk of insulin resistance and β-cell dysfunction: a prospective approach in Tehran lipid and glucose study. Int J Food Sci Nutr. 2015;66(8):950-955.

Image credit: Dustin Kirkpatrick.

Motion graphics by Avocado Video