Vegan Diet and Diabetes: Everything You Need to Know

In recent years, veganism has moved into the mainstream, and many people living with diabetes today eat a vegan diet.

In this post, we will look at the pros and cons of following a vegan diet as a person with diabetes based on the most recent scientific studies. 

The case for following a vegan diet

Although having type 1, type 2, or prediabetes is a life-changing event, there are ways to reduce the symptoms, complications, and stress associated with diabetes.

One of the most impressive ways to decrease the burden could be switching to a more whole-foods, plant-based (WFPB) lifestyle.

In fact, in 2018, the American Association of Clinical Endocrinologists and the American College of Endocrinology released their new guidelines suggesting that a “plant-based diet is the optimal nutrition plan for people with diabetes” because it promotes the well-being and allows people with diabetes to have better management (1).

Today, suboptimal nutrition is a major cause of the increasing epidemic of obesity, chronic disease, and premature deaths worldwide. A diet that is suboptimal is one that is high in sodium and processed meats, and low in dietary fiber, which is found in fruits, vegetables, nuts, seeds, whole grains, and legumes.

Eating a suboptimal diet is associated with 45.5% of all deaths relating to heart disease in the United States (2).

However, recent studies reveal that when someone with diabetes or prediabetes switches from a suboptimal diet to a more WFPB diet not only can it significantly reduce insulin requirements and lower their A1c, but can also increase weight loss, decrease total cholesterol, decrease depression, and increase the quality of life and physical well-being.

If you have diabetes (type 1 or type 2) or have prediabetes, eating a WFPB diet may greatly help you with your diabetes management and coping (3).

Now let’s dig into the research.

Diet terminology

Although vegetarian diets are healthful and are associated with a lower risk of several chronic diseases, different types of vegetarians do not experience the same level of benefits with their diabetes management (4).

There are many types, but for brevity, we will be discussing the following:

• a vegetarian diet
• a vegan diet
• a whole-foods, plant-based (WFPB) diet.

Vegetarian: Do not eat any meat, poultry, or fish, but may consume dairy products and/or eggs (5).

Vegan: Do not eat any foods derived wholly or partly from animals (6).

Whole-foods plant-based: Avoid most or all animal products and supports high consumption of whole, minimally processed, and unrefined ingredients from foods such as fruits, vegetables, legumes, seeds, whole grains, nuts, and seeds (7). This diet is low in fat, high in fiber, and moderate in protein.

What’s the difference between a Vegan Diet and a Plant-Based, Whole-Foods Diet?

The reason it is important to differentiate between a vegan and a WFPB diet is the quality of food. The higher quality is what determines the level of health benefits.

For example, if a person is only living by the rule of a vegan to not eat animal products, they can technically indulge in a diet that is highly processed, high in sodium, high in sugar, high in saturated fat, and low in dietary fiber.

Theoretically, a vegan diet could consist of the following…

• Breakfast: Betty Crocker Bisquick Original Pancakes topped with Golden Griddle Syrup (made with corn and high fructose corn syrup)
• Lunch: Smuckers Peanut Butter and Jelly Sandwich (made with white bread)
• Snack: Lay’s Classic Potato Chips
• Dinner: Hot and Sour Thai Kitchen Noodle Bowls & a serving of Ore-Ida Tater Tots with a side of Ketchup (more high fructose corn syrup)
• Dessert: 1 large Duncan Hines California Walnut Brownie Mix topped with Duncan Hines Chocolate Whipped Frosting

While a WFPB diet would look like..

• Breakfast: Blackberry Smoothie Bowl topped with Coconut Flakes, Pepitas, and Fresh Fruit
• Lunch: Sweet Potato Toast loaded with Mashed Avocado and Roasted Chickpeas
• Dinner: Spaghetti Squash Noodles with Cauliflower Alfredo Sauce
• Dessert: Hemp Seed Energy Bites

Both diets are vegan, but there is a massive difference in the quality and nutrition of the food eaten.

What changes can I expect with my diabetes when I eat a WFPB diet?

Once you start, you may see a change in your blood sugar almost immediately, or it could gradually decrease over the next couple of weeks to months.

Clinical changes you can expect are a reduction in insulin resistance and requirements, a lowered A1c, weight loss, and a decrease in total cholesterol and blood pressure (8, 9).

What changes will I see with my insulin on a plant-based diet?

Looking specifically at insulin, doses may need to be adjusted with your Health Care Provider (HCP) such as a Primary Care Physician (PCP), Endocrinologist or Certified Diabetes Educator (CDE). The reduction varies greatly depending on your needs and your adherence to the diet.

The settings that may need to be tweaked would be the following:

Multiple Daily Injections (MDI):

• Correction Factor
• Insulin to Carb Ratio
• Long-acting insulin

Pump Users:

• Correction Factor
• Insulin to Carb Ratio
• Basal(s)

It is not recommended for you to adjust these settings without an HCP. However, you can expect for your correction factor and insulin carb ratio to increase. This may be confusing, but these numbers use an inverse ratio, meaning the higher the number, the less insulin is used.

For example, you may have a 1:12 insulin-to-carb ratio, meaning you need 1 unit of short-acting insulin to cover 12 grams of carbohydrates.

You then start eating a WFPB diet and notice that when giving insulin for 12 grams of carbohydrates, it causes low blood sugar. Your HCP would then increase your insulin to carb ratio.

In this example, we will say it is increased to 1:15, which means that now 1 unit of short-acting insulin will cover 15 grams of carbohydrates in order to bring your blood sugar back to target after a meal or snack.

This same situation may also occur for your correction factor. For example, if you are used to a 1:25 (1 unit for 25 mg/dL), after starting a WFPB diet, that correction may be too much and you may need to increase your ratio.

Consult your physician or a Certified Diabetes Educator (CDE) when changing these settings. As with any significant dietary change, it is important to closely monitor your blood sugar and regime and adjust your insulin as needed.

For those who see a rise in their blood sugar levels, it does not mean that this new way of eating is not working, but that you may need to change your approach or your body may just need additional time. Remember, for the positive health benefits to occur, you need to make sure to eat a WFPB diet that is low-fat, low-GI, minimally processed, and plant-based (10).

Will I see a blood pressure change eating a WFPB diet?

Many people who have diabetes are also on antihypertensive medication. If this is you, make sure to also bring up your antihypertensive medication with your HCP before making the switch. During that visit, it is also important to go over low blood pressure symptoms and treatment (11).

Should I talk to my healthcare provider before starting a plant-based diet?

Before starting a WFPB diet, consult your HCP in order to discuss any necessary medication changes due to decreased insulin resistance and weight loss.

Also, make sure you know how to treat a low blood sugar. An abrupt change to eating a WFPB diet may result in a great decrease in insulin resistance, which means that those with diabetes who use oral hypoglycemic agents or insulin may encounter low blood sugar (12).

What if I can’t handle beans on a plant-based diet?

The recommended intake for beans on a WFPD is about 1 ½ cups per day. For the average person, that may seem like a lot and give you a little anxiety due to past experiences with beans.

Some people may feel that they do not tolerate beans because of flatulence, but rest assured, adding beans to your diet is a gradual process. Your body will adjust over time as you regularly consume beans.

Start with smaller beans such as peas or lentils because they are easier to digest. Also, if soaking your own beans, make sure to soak thoroughly and discard the water used to soak those beans (13).

Next, start with smaller amounts. For example, start with ½ a cup per day and divide that amount throughout the day. Try eating ¼ cup at lunch and ¼ cup at dinner for a total of ½ cup for that day.

Try this for a week and if tolerable, then increase up to 1 cup of beans per day. Try this for a week and if tolerable, then increase to the final amount of 1 ½ cups per day.

Beans are exceptionally nutritious and filling due to the high amount of dietary fiber and plant protein. Beans are a staple of a WFPB diet, but make sure to add them gradually over at least 3 weeks if you are coming from a diet that does not usually contain beans.

Are there any special considerations eating plant-based if I have diabetes?

Vitamin B12, also known as cobalamin is a nutrient the body needs in order to make red blood cells, nerves, DNA, and carry out other necessary functions. Vitamin B12 cannot be made by the body, therefore it is important to get this either through supplements or from food (14).

Unfortunately, plants do not make Vitamin B12 and the body cannot make it on its own. The only foods that naturally contain Vitamin B12 are meats, eggs, poultry, and other foods that come from animals. Therefore, a strictly vegan diet can cause a Vitamin B12 deficiency.

Additionally, some diabetes drugs, including metformin, have been linked to decreased levels of vitamin B12 (15). Therefore, people with diabetes treated with metformin, especially large doses (such as ≥ 2000 mg/dL) and for longer durations (> 4 years), should regularly be screened for a B12 deficiency.

Other factors that can increase the risk of a Vitamin B12 deficiency are being over the age of 50 and having a weight loss surgery such as gastric bypass (16).

What are vitamin B12 deficiency symptoms?

Vitamin B12 deficiency is serious and early detection is important. Vitamin B12 deficiency can cause tiredness, constipation, weakness, loss of appetite, weight loss, and megaloblastic anemia.

Having a Vitamin B12 deficiency can also increase nerve problems such as numbness and tingling in the hands and feet. Other symptoms of Vitamin B12 deficiency include problems with balance, confusion, depression, poor memory, dementia, and soreness of the mouth or tongue (17).

A thorough HCP may be able to detect a Vitamin B12 deficiency, but a blood test is needed to confirm the diagnosis.

Will I get enough protein eating a WFPB vegan diet?

Sufficient protein is needed to supply nitrogen and amino acids to our cells for growth and maintenance of the protein pool in our bodies (18).

The minimum protein recommendation by the United States Department of Agriculture recommends 46 grams for women and 56 grams for men per day (19).

A WFPB diet can more than exceed this amount of protein by including plants that are rich in protein such as beans, peas, lentils, peanuts, almonds, quinoa, chia seeds, hemp seeds, and dark leafy greens (20).

Eating a diet entirely based on plants provides all the essential amino acids and macro quantities needed, even without the use of special food supplements or combinations (21). Further, eating a diet where the protein comes exclusively from plants has been associated with a reduction in cholesterol, obesity, and heart disease (22).

What about kidney health on a WFPB vegan diet?

An especially alluring benefit to those with a long-standing history of diabetes is that a higher intake of vegetable protein is associated with lower rates of renal failure, meaning that a diet that replaces animal protein with plant protein was found to be more protective for kidney health (23).

Traditional dietary recommendations for renal patients were to limit the intake of fruits and vegetables because of their levels of potassium. However, this recommendation is changing due to multiple benefits from eating a more WFPB diet.

These benefits include improved gut health and a reduction in toxin formation. Also, a WFPB diet is high in dietary fiber which increases regularity and increases production of short-chain fatty acid. Short-chain fatty acids inhibit the growth of harmful bacteria in the gut, increase absorption of minerals like calcium, and help control appetite to increase weight loss (24).

A condition called Metabolic Acidosis in chronic kidney disease (CKD) is aggravated by eating a diet high in meat and refined cereals, which increases the dietary acid load. On the other hand, fruits and vegetables accomplish the opposite by neutralizing acid (25).

High phosphorus levels are also a known cause of cardiovascular death in CKD patients, however, phosphorus absorption is also lower while eating a more WFPB diet since the majority of high phosphorus sources come from highly processed convenience foods, meats, dark-colored sodas, and dairy products (26).

Another benefit of eating a WFPB diet for a CKD patient is the richness of magnesium and vitamin K from eating a variety of plants, which is a common deficiency for CKD patients. These beneficial effects, together with a reduction in inflammation and oxidative stress may slow the CKD progression.

However, it should be noted that there is a higher risk for elevated potassium levels while eating more plants, however a CKD patient can minimize absorption through adequate cooking techniques (27).

How do I get started on a plant-based diet?

8 tips to get started on a Whole-Foods, Plant-Based diet with diabetes

Base your meal on vegetables. Fill at least half your plate with a variety of non-starchy vegetables such as mixed leafy greens, green beans, roasted brussels sprouts, cauliflower, broccoli, asparagus, and cabbage.

Make meat an accent. When (if) you eat meat, reduce the amount and make it the accent rather than the main course of your meal.

Choose whole foods. Choose foods that are whole, minimally processed, and unrefined such as fruits, vegetables, legumes, whole grains, nuts, and seeds.

Choose high fiber. The higher the fiber per serving, the more it tends to cause a lower GI response, which can be exceptionally helpful for those with diabetes. Choose foods such as berries, cruciferous vegetables, nuts, seeds, leafy greens.

Upgrade your fats. Trade out highly processed and saturated fats for fats from whole plant sources such as avocados, olives, nuts, and seeds. Limit fats from oils, you will get more nutrients from eating the whole food.

Build a “Buddha Bowl.” Fill a bowl with salad greens such as romaine, spinach, kale, leafy greens and top with a variety of other vegetables such as beans, peas, edamame, Brussel sprouts, and sautéed mushrooms.

Eat fruit for dessert. Enjoy a large bowl of fresh berries, a crisp apple with peanut butter, or a serving of blended banana ice cream to satisfy your sweet tooth after a meal.

Consult your doctor. As you change your eating habits, it is important to adjust insulin and medications with a Health Care Provider such as a PCP, an Endocrinologist or a Certified Diabetes Educator (CDE).

Conclusion

Eating Whole-Food, Plant-Based has many potential health benefits for people living with diabetes. However, it is not necessary to completely eliminate animal products from your diet to receive these benefits.

Plant-based means that the foundation of the foods you consume are from plants, but that does not mean that all animal products must be completely removed from your diet.

Eating a highly restrictive diet such as a diet without any animal products can be mentally challenging and can for some lead to orthorexia or other eating disorders.

Therefore, if you decide to eat a WFPB diet, it should be seen as a lifestyle and not an extreme diet that does not allow for wiggle room.