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Insulin resistance, diabetes and nutrition

Approximately 463 million people have diabetes in the world. The International Diabetes Federation reported that there are 1.8 million South Africans living with diabetes. However, it estimates an additional undiagnosed population of 69% of the total number of diabetics. The African continent is expected to see the highest increase in diabetes globally by 2045 from 19 million to 47 million.


Whilst type 2 diabetes has several causes, genetics and lifestyle choices seem to be the most important ones. This means that for those 463 million people with diabetes in the world, changing lifestyle can be a big step towards managing the disease and even reversing it.


Diabetes starts with high insulin. Insulin is a hormone made by the pancreas that helps glucose in your blood enter cells in your muscle, fat, and liver, where it’s used for energy. Glucose comes from the food you eat. The liver also makes glucose in times of need, such as when you’re fasting. When blood glucose, also called blood sugar, levels rise after you eat, your pancreas releases insulin into the blood. Insulin then lowers blood glucose to keep it in the normal range. In people with insulin resistance, the cells are unable to use insulin effectively and this can ultimately lead to high blood sugar.  This increases the risk of developing prediabetes, and eventually, type 2 diabetes.


As previously mentioned, people who have genetic or lifestyle risk factors are more likely to develop insulin resistance or prediabetes. Risk factors include:

  • Being overweight or obese
  • age 45 or older
  • having a parent, brother, or sister with diabetes
  • physical inactivity
  • health conditions such as high blood pressure and abnormal cholesterol levels
  • a history of gestational diabetes (diabetes during pregnancy)
  • a history of heart disease or stroke
  • Polycystic ovarian syndrome (PCOS)

As glucose comes from the food you eat, it makes sense that making dietary changes will impact the amount of glucose in your blood, and help you reverse insulin resistance and thereby decrease your risk of developing type 2 diabetes.  There are many dietary interventions that have been shown to be beneficial in both insulin resistance and type 2 diabetes and some of these are discussed below. Ultimately, the best diet for you will largely come down to your genetics and your ability to follow the diet long term.

Mediterranean diet

The foundation of the Mediterranean diet is vegetables, fruits, herbs, nuts, beans and whole grains as well as olive oil. Meals are built around these plant-based foods. Moderate amounts of dairy, poultry and eggs are also central to the Mediterranean Diet, as is seafood. It has proved to be associated with greater improvement of insulin resistance in obese individuals, when compared to other nutritional interventions. The nutrients that are found in abundance in the Mediterranean diet have anti-cancer, anti-inflammatory and anti-obesity properties.


The general guidelines of the diet recommend that people eat:

  • a wide variety of vegetables, fruits, and whole grains
  • healthful fats, such as nuts, seeds, and especially olive oil
  • moderate amounts of dairy and fish
  • some white meat and very little red meat
  • few eggs
  • red wine in moderation

Vegetarian and vegan diets

In research, a calorie-restricted vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat (fat that wraps around your abdominal organs) and improvements in other markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet. Additionally, a low-fat vegan diet, has been associated with decreased fat mass and insulin resistance, and enhanced insulin secretion.


A vegetarian diet typically excludes meat, poultry, fish and seafood. Whereas a vegan diet excludes all meat and animal products including dairy, eggs and often honey. Extra attention has to be paid in vegetarian and vegan diets to attain all the nutrients required to support health – like iron, vitamin B12 and vitamin D, to name a few.


Low carbohydrate diets

Low carbohydrate diets have also been shown to be effective in reversing insulin resistance and possible remission of type 2 diabetes.  A low-carb diet is one that limits carbohydrates, primarily found in sugary foods, pasta, and bread. Instead of eating carbs, you eat whole foods including natural proteins, fats, and vegetables.  This can also be called a low-carb, high-fat diet (LCHF) or a keto diet However, not all low-carb diets result in ketosis.

Low-carb foods include:

  • lean meats, such as sirloin, chicken breast, or pork
  • fish
  • eggs
  • leafy green vegetables
  • cauliflower and broccoli
  • nuts and seeds, including nut butter
  • oils, such as coconut oil and olive oil
  • some fruit, such as apples, blueberries, and strawberries
  • unsweetened dairy products including plain whole milk and plain Greek yogurt

A Paleolithic diet

A Paleolithic diet has been shown to improve fat mass and metabolic balance including insulin sensitivity in type 2 diabetes. It has also been found to be instrumental in weight loss.

A Paleolithic diet is a dietary plan based on foods similar to what might have been eaten during the Paleolithic era. A Paleolithic diet limits foods that became common when farming emerged about 10,000 years ago.

What to eat

  • Fruits
  • Vegetables
  • Nuts and seeds
  • Lean meats, especially grass-fed animals or wild game
  • Fish, especially those rich in omega-3 fatty acids
  • Oils from fruits and nuts, such as olive oil or walnut oil

What to avoid

  • Grains, such as wheat, oats and barley
  • Legumes, such as beans, lentils, peanuts and peas
  • Dairy products
  • Refined sugar
  • Salt
  • Potatoes
  • Highly processed foods in general

Whilst changing what you eat is critical in managing insulin resistance and type 2 diabetes, exercise is also crucial. If you’re insulin resistant, exercise actually makes your insulin more effective. That is, your insulin resistance goes down when you exercise, and your cells can use the glucose more effectively. Exercise can also help people with type 2 diabetes avoid long-term complications, especially heart problems.

As you can see, many diets have been shown to be effective in reversing insulin resistance and managing diabetes. What is imperative is to work with a healthcare provider who can help you get onto the right diet and exercise regime to manage your condition. Remember, insulin resistance and diabetes are mostly diseases of lifestyle which means that by changing your lifestyle you can change the course of your disease.