Is a plant-based diet good for diabetes?
Key Takeaways
Plant-based diets can help improve blood glucose control and overall health.
A well-planned plant-based diet is important to help meet your nutritional needs.
A plant-based diet does not have to be restrictive and can be tailored to your needs and preferences.
What is a plant-based diet
A plant-based diet emphasizes wholegrains, legumes, vegetables, fruits, nuts, and seeds, and discourages most or all animal products.
Studies have shown improved blood glucose control, body weight, blood cholesterol levels, and blood pressure following the adoption of a plant-based diet.
As plant-based diets use fewer natural resources, they are also more environmentally sustainable than diets rich in animal products.
Can a plant-based diet be good for diabetes?
Type 2 diabetes is characterised by insulin resistance and there has been increasing evidence that this can be modulated by a plant-based diet. Insulin is produced by the pancreas and helps blood glucose move into the body’s cells for storage. Insulin resistance is when the cells do not respond to insulin properly, causing excess glucose to stay in the bloodstream (i.e. high blood glucose levels).
Research has found that compared to other “diabetes diets”, plant-based diets were associated with a 0.4% greater reduction in glycated haemoglobin (HbA1c). A plant-based eating pattern has also been associated with a reduced risk of diabetes-related complications (e.g. heart disease, chronic kidney disease, nerve damage).
High in Fiber
Many plant-based foods are rich in fiber, antioxidants, and magnesium, all of which have been shown to improve blood glucose control by helping insulin work better.
Fiber, which is found only in plant foods, can also help lower post-meal blood glucose levels. Furthermore, dietary fiber has been linked to decreased inflammation and improved gut health which reduces insulin resistance.
Low in saturated fat
Plant-based diets tend to be low in saturated fat and this can help improve insulin resistance. Saturated fat, which is found primarily in animal-based foods, causes fat accumulation within muscle and liver cells and impairs insulin function. The effects of fat intake on blood glucose levels can also be observed after single meals – meals high in saturated fat can cause blood glucose levels to remain high for a long period of time after the meal.
Saturated fat also increases inflammation and oxidative stress, which can cause damage to the cells of the pancreas. On the other hand, plant-based diets are high in phytochemicals (e.g. polyphenols) that protect pancreatic cells from oxidative stress and damage, improve pancreatic function, and enhance glucose uptake from the bloodstream.
Promotes weight loss
Plant-based diets promote weight loss and a reduction in body fat, which reduces insulin resistance. Plant-based diets are typically higher in fiber and lower in fat than most diets which leads to a reduction in calories consumed throughout the day. The amount of calories needed to digest a meal is also higher for a plant-based meal. This affects energy balance (↓ calories in, ↑ calories out) which aids in weight loss.
Reduction in risk of diabetes-related complications
Compared to omnivorous diets, plant-based diets showed significant improvements in cardiovascular risk factors, including blood cholesterol levels, blood pressure, chronic inflammation, blood glucose control, body weight, and body fat. In addition, a plant-based diet may help reduce plaque build-up in arteries, and reduce the risk of nerve and kidney damage.
It is also promising to note that many studies found that adherence to a plant-based diet was comparable to that of other diets. Not having to limit portion sizes, or count calories or carbohydrates, are some reasons cited to help with offsetting the challenges that come with restricting animal products.
Can a plant based diet help to reverse diabetes?
The American Diabetes Association uses the term “diabetes remission”, defined as the maintenance of normal blood glucose levels (or HbA1c <6.5%) without the use of diabetes medication for at least 3 months.
Plant-based diets show promise at improving blood glucose control, and frequent monitoring is recommended so medication adjustments can be discussed with your doctor accordingly.
What are the challenges when adopting a plant-based diet for diabetes?
With any diet, acceptability is crucial to ensuring long term sustainability. Some who do not like the taste or flavour of vegetables, wholegrains, beans, or soy-based foods may struggle to find a wide enough variety of foods they can enjoy or find a plant-based diet restrictive and unsustainable.
Additionally, having diversity in the diet helps meet nutritional requirements, especially that of vitamins and minerals. Table 1 outlines the dietary sources of certain key nutrients that could be lacking if a plant-based diet was not well-planned.
Table 1: Dietary sources of key nutrients on a plant-based diet
| Nutrient | Role | Dietary Sources |
|---|---|---|
| Protein | Maintains lean muscle mass and supports the immune system | Soy products (e.g. soy milk, tofu, tempeh) Legumes (e.g. beans, lentils) Chickpeas Edamame Nuts & seeds |
| Calcium | Beneficial for strong bone, teeth and muscle function | Fortified plant milks Green leafy vegetables (e.g. kai lan, spinach, chye sim) Silken tofu Tau kwa Almond |
| Iron | Aids the transport of oxygen in the blood | Tofu Legumes Green leafy vegetables Wholegrains Fortified cereals |
| Omega-3 | Protection against heart disease, anti-inflammatory | Flaxseed oil Chia seed Walnuts |
| Zinc | Beneficial for healthy skin and immunity | Nuts Tofu Miso Legumes Wholegrains |
Vitamin B-12, which is essential for red blood cell production and nerve and brain function, is often lacking in a plant-based diet. Although cereals, plant-based milk, and other plant-based foods may be fortified with vitamin B-12, supplementation may be needed to ensure adequacy. Metformin use also increases the risk of vitamin B-12 deficiency.
Precautions when adopting a plant-based diet
Starting any new diet requires some planning to ensure that you are obtaining an adequate balance of protein, fat, and carbohydrates to meet your nutritional needs and maintain good blood glucose control. As many plant-based foods contain carbohydrates, adopting a plant-based diet without proper planning could cause a significant increase in carbohydrate intake, resulting in higher blood glucose levels.
If you are pregnant or breastfeeding, it is possible to meet your nutritional requirements if you are including a variety of foods from each food group and eating sufficiently. Some women will need supplements, especially vitamin B-12, which is crucial for supporting the baby’s brain development. Vitamin B-12 deficiency can also cause anemia in the mother.
Omega-3 supplements (e.g. marine algae supplements), which help with the brain and eye development of the baby, may also need to be considered.
Speak to your doctor before starting a plant-based diet as the dietary changes could affect your blood glucose levels and require an adjustment of medications. You should also monitor your blood glucose levels using a glucometer or continuous glucose monitor when starting on a plant-based diet.
What about plant-based meat alternatives?
As plant-based meat alternatives taste similar to meat, they can help with the transition to a plant-based diet. Many are comparatively lower in saturated fat and a good source of fiber as well.
Do note however that some options can be high in saturated fat as manufacturers may use palm and coconut oils to give products a similar mouthfeel to ground beef. Read the food labels on meat substitutes to determine fat content.
Many meat substitutes also contain food allergens (e.g. soy, wheat, tree nuts) and additives (e.g. artificial colours, flavours, added sugars, sugar substitutes, gums). People with food allergies or intolerances will need to read ingredient labels carefully.
Plant-based meats are processed foods and while they can fit into a healthful diet, it is best to choose whole food options (i.e. legumes, wholegrains, vegetables, fruits, nuts, and seeds) as much as possible. Similarly, refined grains and added sugars should be limited as they often lack nutrients and are associated with weight gain, insulin resistance, and poorer blood glucose control.
What can I do if I cannot stick to a plant-based diet?
To see long-term results from any diet, adherence and sustainability are key. A plant-based eating pattern emphasizes legumes, wholegrains, vegetables, fruits, nuts, and seeds. For some, this does not mean a total exclusion of animal products . There are some vegetarians who include eggs and dairy in their meals, pescatarians include fish and seafood, and flexitarians include some meat products in their meals occasionally.
Here are some suggestions on how you can start to adopt a more plant-based eating pattern:
Start by filling half of your plate with vegetables. Make sure you include plenty of colours to obtain a range of different nutrients.
Choose one or two days/meals per week to experiment with plant-based eating. Swap out animal protein for plant-based protein sources (e.g. tofu, tempeh, beans, edamame).
Swap out refined grain options for wholegrain options (e.g. white rice/bread → brown rice/wholegrain bread, cornflakes → oats, prata → chapati). You can also try other wholegrain options (e.g. quinoa, buckwheat, millet, barley).
Choose unsaturated fat options (e.g. olive oil, avocado, nuts and nut butters, seeds).
Eat fruit for dessert – this can help satisfy sweet cravings after a meal.
Choose whole food options for snacks (e.g. nuts, seeds, fruit, vegetable sticks with hummus/guacamole).
That being said, a plant-based diet may not be for everyone and it is not the only healthy eating pattern for improving blood glucose control. The key is to focus on the principles of a healthy diet: having well-balanced meals, choosing whole food options, and limiting fat, sugar and salt intake.
Getting support
Adopting a plant-based diet can be challenging at the start but you do not have to do it on your own. NOVI Magnum is our complete diabetes care package which provides expert guidance from a dietitian who can help provide guidance and tailor your diet based on your needs and preferences.