How to reverse type 2 diabetes with plant-based diet

by Dr Sue Kenneally

Giving someone a diagnosis of type 2 diabetes isn’t a great day in the office for your average GP. It means explaining that the person concerned is now at risk of complications of diabetes, and also at increased risk of other health problems including high blood pressure, kidney disease and cardiovascular disease among others. They are going to almost certainly need regular medication, and at least annual check-ups, regular blood tests and constant monitoring of their blood sugars.

But here’s the thing. For 90% of people who are diagnosed with type 2 diabetes, the condition is reversible. And largely in the control of the person themselves because it’s all about changing their lifestyle. This is different from type 1 diabetes, which is a different condition and not the subject of this present article.

Type 2 diabetes

Type 2 diabetes is caused when the body no longer responds to insulin as it should. The pancreas still makes insulin, but it just doesn’t work as effectively. This is known as insulin resistance and is the underlying problem in type 2 diabetes. It is strongly associated with overweight, so most people who have type 2 diabetes, but not all, are also living with a higher body weight. If you have type 2 diabetes and are living with a higher body weight then the key to reversing diabetes is losing the excess weight, as the lifestyle changes that result in weight loss also reverse insulin resistance to some extent, essentially healthy diet and regular exercise. If you have a body weight in the healthy range but still have type 2 diabetes, then the aim is still healthy diet and regular exercise as these improve your insulin resistance independently of whether or not you need to lose weight.

Insulin resistance is made worse by excess fat around the organs in the abdomen, so called ‘visceral’ fat, and in the liver and skeletal muscles, so a diet that reduces this fat is desirable when intending to reverse diabetes.

The evidence

A number of high-quality clinical trials have assessed the effects of a whole food plant-based diet on type 2 diabetes and insulin, and the results are very encouraging, see the references section below for details. They consistently show that a whole food plant-based diet can result in significant weight loss in those living with excess body weight, and reduce insulin resistance, the amount of fat associated with insulin resistance, and blood sugars.

So, what do I eat?

The great news is that a whole food plant-based diet is an effective way to reverse diabetes through weight loss and reducing insulin resistance, but what does this look like? 

Essentially, it’s a diet based on fruits, vegetables, legumes, nuts, seeds, and wholegrains. People frequently ask me about low carbohydrate diets and diabetes, because intuitively if you have a condition where you can’t handle carbohydrate effectively then avoiding carbohydrate would seem sensible. A low carbohydrate diet isn’t necessary, not least because if you’re not eating carbohydrate then you must be eating something else instead, either high protein or high fat, and neither of those are recommended in diabetes. 

It’s very true that it’s important to avoid refined carbohydrates if you have type 2 diabetes, by which I mean good old-fashioned sugar and others like white flour and baked goods. These have a high glycaemic index which means that when you eat them your blood sugar rises quickly, not ideal when your insulin that is supposed to reduce your blood sugar when needed isn’t functioning properly. But whole foods containing naturally occurring carbohydrate like fruits, vegetables and whole grains have a low glycaemic index, meaning that they are healthful to eat if you have type 2 diabetes.

The evidence shows that a whole food plant-based diet is effective in promoting weight loss, reducing insulin resistance, reducing the fat associated with insulin resistance and reversing type 2 diabetes. 

References

1. 1. Barnard ND, Levin SM, Gloede L, Flores R. Turning the Waiting Room into a Classroom: Weekly Classes Using a Vegan or a Portion-Controlled Eating Plan Improve Diabetes Control in a Randomized Translational Study. J Acad Nutr Diet. 2018 Jun 1;118(6):1072–9.
2. Barnard ND, Cohen J, Jenkins DJ, Turner-McGrievy G, Gloede L, Green A, et al. A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial. Am J Clin Nutr. 2009 May 1;89(5):1588S-1596S.
3. Chen Z, Zuurmond MG, van der Schaft N, Nano J, Wijnhoven HAH, Ikram MA, et al. Plant versus animal based diets and insulin resistance, prediabetes and type 2 diabetes: the Rotterdam Study. Eur J Epidemiol. 2018 Sep 1;33(9):883–93.
4. Kahleova H, Petersen KF, Shulman GI, Alwarith J, Rembert E, Tura A, et al. Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial. JAMA Netw open. 2020 Nov 2;3(11):e2025454.
5. Toumpanakis A, Turnbull T, Alba-Barba I. Effectiveness of plant-based diets in promoting well-being in the management of type 2 diabetes: A systematic review. Vol. 6, BMJ Open Diabetes Research and Care. BMJ Publishing Group; 2018. p. 534.
6. Turner-McGrievy GM, Jenkins DJA, Barnard ND, Cohen J, Gloede L, Green AA. Decreases in dietary glycemic index are related to weight loss among individuals following therapeutic diets for type 2 diabetes. J Nutr. 2011 Aug 1;141(8):1469–74.
7. Kahleova H, Tura A, Hill M, Holubkov R, Barnard ND. A plant-based dietary intervention improves beta-cell function and insulin resistance in overweight adults: A 16-week randomized clinical trial. Nutrients. 2018 Feb 9;10(2).
8. Barnard ND, Scialli AR, Turner-McGrievy G, Lanou AJ, Glass J. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am J Med. 2005 Sep 1;118(9):991–7.