Plant-Based Diets and Diabetes

The prevalence of diabetes has been increasing over the past few decades. In 2019, about 463 million adults worldwide were diabetic, the majority living in low-and middle-income countries, with that number estimated to reach 700 million adults worldwide by 2045. Could a plant-based diet play a role in helping prevent and treat diabetes?

What is Diabetes?

Diabetes is a condition in which your blood sugar level rises too high. It can happen when your body does not produce enough insulin (type 2 diabetes) or does not produce any insulin at all (type 1 diabetes).^1,2,3 Insulin helps your body regulate its sugar levels by sending signals to the cells in your muscles, fat and liver to take up glucose. So when your body cannot produce enough insulin or has become insulin resistant, it is harder for your cells to take up glucose and use it to produce energy - this can cause fatigue and hunger, among other symptoms. High blood sugar can also cause long-term consequences such as blood vessel damage, which can induce heart attacks, kidney failure and even blindness.^4,5

How Can Plant-Based Diets Help Prevent Or Treat Type 2 Diabetes?

As part of their treatment, people with diabetes and those at risk of diabetes must often change their eating habits. Several studies have shown that balanced plant-based diets can be effective in the prevention and management of type 2 diabetes in a number of ways.

1. Fewer Spikes In Blood Sugar Levels

You might have noticed that most people with diabetes are careful about their food and drink intake. One of the reasons for this is to prevent the blood sugar ‘roller-coaster effect’, as blood sugar spikes may be followed by a dangerous downward sugar spiral. Sugar spikes can also cause further complications for those with type 2 diabetes, such as cardiovascular and renal diseases.

People with diabetes need to be aware of which types of carbohydrates they consume, as certain types of carbohydrates (like refined and low-fibre carbs) can increase insulin and blood sugar levels - making them potentially harmful to people with or at risk of type 2 diabetes.^4,5  The type of carbohydrate also affects blood sugar levels. When carbohydrates come in liquid form, like orange juice, they will raise blood sugar levels much more than a piece of fruit that retains its fibre - as the presence of fibre helps control blood sugar levels.^4,5,6,7

A balanced plant-based diet is usually characterized by lots of nutrient-dense and high-fibre foods such as legumes, whole grains, vegetables, fruits and nuts. Fibre-rich foods like these are slowly digested by the body, which creates small fluctuations in blood sugar levels and reduces the risk of high blood sugar levels. 

It’s important to note that there is a common misconception that diabetics should avoid carbohydrate-rich foods. In fact, several studies have found that low-carbohydrate diets increase the risk of type 2 diabetes - so carbohydrates should not be left out of the diet entirely.⁴ 

2. Weight-Loss From A Plant-Based Diet

As obesity is one of the main causes of type 2 diabetes, weight loss as a result of switching to a healthier and more balanced plant-based diet might be effective at preventing and treating type 2 diabetes. The increased intake of fibre-rich foods can lead to weight loss as high-fibre foods promote a feeling of fullness, reducing further intake of energy-dense foods - which also helps reduce insulin resistance.^4,5,6

Find out about the "food deserts" behind unequal access to healthy diets 

3. Improved Insulin Sensitivity

Food microbiome interactions can also improve insulin sensitivity. Additionally, high-fibre plant foods can help lower or prevent insulin resistance. After eating fibre-rich foods, the fibre is fermented by beneficial bacteria in your gut. The fermentation process produces ‘short-chain fatty acids’ that improve insulin signalling and glucose uptake.⁵ Plant-based diets are also often high in phytonutrients, antioxidants and magnesium, all of which have been shown to promote insulin sensitivity, reduce insulin resistance and improve your body’s control over blood sugar levels. 

4. Improved Blood Sugar Control

Studies have also shown that saturated fat, mainly found in animal-based foods, can block insulin from signalling muscle and liver cells. This is because saturated fat can lead to the accumulation of ceramide (toxic fat metabolites) in muscle and liver cells. Similar to insulation in walls blocking noise from entering your home, ceramide allows fewer signals from insulin in your blood to reach muscle and liver cells. As a result, your cells cannot uptake glucose and turn it into energy.⁴  Therefore, balanced plant-based diets, which are generally low in saturated fats, can improve insulin sensitivity, which allows muscle and liver cells to uptake sugar - keeping your blood sugar controlled.

5. Lower inflammatory response

Even though inflammation is a natural immune response that protects us against infection and injury while promoting healing, when that response is constantly triggered in the long term, it can damage the body cells instead of healing them. Fibre, part of a balanced plant-based diet, has been linked to decreased inflammation, which may also help lower insulin resistance. Additionally, several studies have shown that those who follow a plant-based diet have significantly less obesity-related inflammation response.⁴