Type 2 diabetes

The disease

Diabetes is the fastest growing chronic condition in Australia and New Zealand. More than 1.2 million Australians are living with known diabetes, while many more remain undiagnosed. Prevalence of diabetes in Australia has tripled over the past 25 years and there is no sign of this slowing. In New Zealand, It is expected that 7% of the population will have diabetes by 2040.

Type 2 diabetes mellitus (type 2 diabetes) represents approximately 85% of all cases of overall diabetes. There are significant long-term health risks associated with the disease; it is a major cause of blindness, kidney failure, heart attacks, stroke and lower limb amputation.

It is largely preventable with lifestyle modifications. Type 2 diabetes can be prevented or delayed in up to 58% of people by following a healthy eating plan, maintaining a healthy weight and being active.

The cause

The underlying mechanism of type 2 diabetes is insulin resistance. Contrary to popular belief, it is not carbohydrates or sugar that cause insulin resistance. Insulin resistance is caused by a build-up of fat inside muscle and liver cells. Fat stored in these cells reduces their sensitivity to insulin, resulting in increased blood glucose levels.

Changes begin in the body long before a person is diagnosed with type 2 diabetes, it often takes years to develop. The early stages are characterised by insulin overproduction; eventually cells stop responding to the increased levels of insulin, then the pancreas keeps making more insulin to try to make cells respond. Eventually, the pancreas can’t keep up, and blood sugar keeps rising.

As body weight increases, so too does risk of this disease. Being overweight means there is more fat stored within cells, which can impact how well insulin works.

The blame for the current diabetes epidemic lies in an overall dietary pattern emphasising meat, dairy products, fatty foods, and sugary foods and beverages, rather than simply sugar alone. A diet emphasising vegetables, fruits, whole grains, and legumes and avoiding animal products helps prevent diabetes and improves its management when it has been diagnosed.

Although the idea that “eating sugar causes diabetes” is inaccurate, avoiding added sugars is a helpful step, and it should be taken as part of a healthful plant-based eating pattern, not instead of it. Besides dietary patterns other major risk factors include smoking and physical inactivity. Family history and genetic susceptibility contribute only a small component to type 2 diabetes risk.[1]

The nutrition prescription

Nutrition and lifestyle management is recommended as a first-line therapy for newly diagnosed cases of insulin resistance and type 2 diabetes, however, it is reported that only 5-10% of patients are given any opportunity to manage the condition without pharmaceutical intervention.[2]

Evidence on nutritional interventions demonstrates that a whole food plant-based eating pattern is highly effective in both the prevention and treatment of type 2 diabetes, including lasting resolution:

  • The Adventist Health Studies have found that vegetarians have approximately half the risk of developing diabetes as nonvegetarians. [3],[4]
  • Randomised controlled trials have shown that in many cases type 2 diabetes can be stopped and reversed on a low fat whole food plant-based diet. [5],[6]
  • A whole food plant-based eating pattern also provides the best chance of avoiding long term complications, and increasing quality of life and life expectancy for all people with diabetes. [4],[6]

A healthy low-fat whole food plant-based diet provides abundant dietary fibre, well in excess of the recommended fibre intake per day. This high fibre intake not only assists with weight management but also better blood glucose control.

Those following plant-based diets often have a lower body mass index and reduced waist circumference. There is also no need to restrict how much you eat, removing the need for calorie counting, making managing your diet much easier.

The fact that common biological processes underpin virtually all chronic diseases means that with a whole food, plant-based way of eating, you are not just reducing one risk factor, but having an influence on them all.


Medical supervision of diet change is essential

Shifting to a low fat plant-based diet can lead to rapid reductions in medication needs for diabetic patients, and must only be undertaken under medical supervision.


Video overview from NutritionFacts.org

Patient recovery testimonial from Forks Over Knives: NY Mayor

Further resources

Plant Based Health Australia logo

Plant-based Health Australia: an up-to-date review of the evidence base on diabetes and diet, with detailed references and case studies.

PCRM logo

Physicians Committee for Responsible Medicine: summary, 18-minute TEDx video, fact sheet download and links to related articles.

FAQs

Glucose, also known as blood sugar, is the body’s main source of fuel. Because blood sugar levels are high in diabetes, a common notion has held that eating sugar somehow triggers the disease process. Insulin resistance is caused by a build-up of fat inside muscle and liver cells, not consuming sugar. Read a more in-depth article from Physicians Committee of Responsible Medicine on this topic.

Confusion about the role of carbohydrates in the causation and management of type 2 diabetes has led to increased popularity of low carb and ketogenic diets, where all carbohydrate intake is kept to a minimum.

In actual fact it isn’t the amount of carbohydrates, it is the type that needs to be considered. Complex, unrefined carbohydrates, found in whole plant foods, are full of fibre and nutrients and can actually lower blood sugar and improve type 2 diabetes.

There is no denying short-term use of low carb diets may lead to weight loss and subsequent improvement in glucose control, but the improvements are due to the reduction in energy intake and weight loss. Anything that causes weight loss via simple calorie restriction, even interventions as dramatic as chemotherapy or bariatric surgery, will improve glucose control and insulin sensitivity.

Eating unrefined carbohydrates, naturally packaged with fibre and phytonutrients, is associated with some of the lowest rates of chronic disease, and that includes fruit. Randomised studies have shown that a low-fat vegan diet, high in fruit and vegetables, can reduce insulin resistance by reducing the amount of fat inside the cells and can be an effective treatment for type 2 diabetes patients.[7] Read more on this topic in the book Eating Plant-Based: Scientific Answers to Your Nutrition Questions, written by our International Advisor Dr Shireen Kassam and Dr Zahra Kassam.

Low carb and ketogenic diets might appear to deliver a short-term quick-fix to control type 2 diabetes but there are serious longer-term risks.

The most common underlying causes of death for people with type 2 diabetes are heart disease, cancer and stroke. It is well-established that diets low in fibre and high in saturated fat, just like the aforementioned diets, are associated with an increased risk for these diseases.

Weight-loss may be your first goal to set you on the path to managing type 2 diabetes but a healthy diet over the long-term is critical to avoid exacerbating other diabetes-related health problems. A healthy whole food plant-based diet will deliver weight loss and prevent the future complications of type 2 diabetes.

  1. DeFronzo RA, Ferrannini E, Groop L, et al. Type 2 diabetes mellitus. Nat Rev Dis Primer. 2015;1(1):1-22. doi:10.1038/nrdp.2015.19
  2. Forouhi NG, Misra A, Mohan V, Taylor R, Yancy W. Dietary and nutritional approaches for prevention and management of type 2 diabetes. BMJ. 2018;361:k2234. doi:10.1136/bmj.k2234
  3. Vang A, Singh PN, Lee JW, Haddad EH, Brinegar CH. Meats, processed meats, obesity, weight gain and occurrence of diabetes among adults: findings from Adventist Health Studies Ann Nutr Metab. 2008;52(2):96-104. doi:10.1159/000121365
  4. Tonstad S, Stewart K, Oda K, Batech M, Herring RP, Fraser GE. Vegetarian diets and incidence of diabetes in the Adventist Health Study-2. Nutr Metab Cardiovasc Dis. 2013;23(4):292-299. doi:10.1016/j.numecd.2011.07.004
  5. 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. doi:10.3978/j.issn.2223-3652.2014.10.04
  6. 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. doi:10.11909/j.issn.1671-5411.2017.05.009
  7. Kassam, S; Kassam, Z (2022) Eating Plant-Based: Scientific Answers to your Nutrition Questions

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