Insulin resistance

What is it, what causes it and how can you overcome it?

First of all, let’s discuss what insulin is.  Insulin is a hormone produced by the pancreas, a small organ that sits just under your stomach. Insulin is responsible for keeping your blood sugar (glucose) levels down.

When you eat food, it gets digested and broken down into its basic units. Carbohydrate for instance, is digested in the stomach and broken down into glucose. Glucose leaves the stomach and enters the small intestine. From there the glucose is absorbed into your blood stream. In order to use the glucose as energy it needs to leave the blood stream and enter your cells (e.g. muscle cells, lung cells, brain cells) where it gets burned for energy.

In order for the glucose to enter your cells you need insulin. Insulin acts a bit like a key to a door. Insulin unlocks the cell door so that glucose can move out of your blood into your cells.

People with Type 1 diabetes do not make any insulin. Insulin is therefore the main treatment for people with Type 1 diabetes. A person with Type 1 diabetes cannot live without taking insulin. There is currently no cure for Type 1 diabetes.

Some people make insulin but not enough to manage their blood sugar levels (as in the case of SOME people with Type 2 diabetes, gestational diabetes and people with secondary diabetes).  Lifestyle changes, weight loss and changes to your diet can help to lower blood sugars but due to the nature of their individual diabetes they may end up needing medication or insulin to help support their body in managing their blood glucose.

Most people with Type 2 diabetes however do produce enough insulin but the inulin is not able to do what it is supposed to do. Remember, I said that insulin is a bit like a key that unlocks the cell door so that glucose can move out of your blood into your cells? If the cell door is blocked, then insulin cannot open the door and glucose cannot move into the cell resulting in high blood sugars. This is referred to as insulin resistance. Although insulin resistance is present in most people with Type 2 diabetes it can also be present in people with other types of diabetes including Type 1 diabetes.

So, what causes insulin resistance?

1.       Excess body weight

When we carry excess body weight, then the excess body fat blocks the cell “key hole”. The insulin cannot open the cell door resulting in high blood sugars. This is more likely the case in people with Type 2 and gestational diabetes but if you have Type 1 diabetes and carry excess weight then you can also become insulin resistant. You may have noticed that your insulin requirements increase when you have gained weight. Losing excess weight can help to overcome insulin resistance.

2.       High fat food.

Fatty meals, especially meals high in saturated fat, increase insulin resistance. When we eat fat the body breaks it down into fatty acids. High levels of these fatty acids build-up in the cells resulting in the insulin being unable to unlock the cell door. This may lead to a rise in your blood sugars several hours after a high fat meal…think fish and chips or pizza!

3.       Protein

Studies suggest that consuming a high protein diet in the long term, especially animal protein, increases your risk of developing insulin resistance. In the short term, eating excess protein can also increase your blood sugars several hours after a meal. Many people think that protein has no effect on blood sugars. However, when we digest protein, we break it down into amino acids (the building blocks of protein). The body uses the amino acids to build and repair muscle and other cells. However, any excess protein that the body does not use for build and repair will be converted into glucose. You may thus find that after a meal high in protein your blood sugar can start to rise 2-3 hours post meal.

4.       Hormones

Hormones can play havoc with our blood sugars. Hormones generally increase our insulin resistance making insulin less effective. Women may find that the week before their period their blood sugars are higher than normal. Also going through menopause will increase your insulin resistance.

5.       Emotional and physical stress

Emotional stress and physical stress such as trauma, illness, headaches and injury causes a release of stress hormones such as cortisol, adrenaline and noradrenaline. These stress hormones make us more insulin resistant resulting in higher blood sugars.

6.       Exercise

Most people associate exercise with hypo’s but some types of exercise may actually increase your blood sugars. Think weight training, competitive sport, sprints and HIIT exercise. You can blame your stress hormones for this again!

Can we do anything to reduce insulin resistance?

Yes! There is a lot we can do to reduce insulin resistance almost immediately.

1.       Aim for a low-fat diet in particular try to reduce your intake of saturated fat and trans fats.

2.       Reduce your protein intake especially protein from animals and processed meats.

3.       Increase your fibre intake. Aim for 30g fibre every day. Fibre is great for lowering insulin resistance.

4.       Reduce your intake of highly processed foods. Processed foods are typically low in fibre and nutrients and can be high in fat.

5.       Adopt a whole food plant based (WFPB) diet.  WFPB diets by their nature are low in fat, low in animal protein and high in fibre. WFBP diets have shown to be effective in reducing insulin resistance.  

6.       Try to do regular, moderate intensity exercise at least every 2-3 days to maintain insulin sensitivity.

7.       Make time to relax or to do some relaxation exercises every day e.g., yoga.

8.       If you have type 1 diabetes, then you may have to alter how you take your quick acting insulin to match your insulin with the delayed rise caused by fat and protein.

9.       If you carry excess weight, then try to lose some weight.

Summary

Insulin resistance causes high blood sugars however it is possible to overcome insulin resistance and achieve your target blood sugars by making changes to your diet and lifestyle.

References

Wendy et al. (2016)  Impact of Diet Composition on Blood Glucose Regulation, Critical Reviews in Food Science and Nutrition, 56:4, 541-590.  

Kirstine et al. (2015). Impact of Fat, Protein, and Glycaemic Index on Postprandial Glucose Control in Type 1 Diabetes: Implications for Intensive Diabetes Management in the Continuous Glucose Monitoring Era. Diabetes Care 38 (6): 1008–1015

Roden. (2004) How Free Fatty Acids Inhibit Glucose Utilization in Human Skeletal Muscle, Physiology 19:3, 92-96

Orlich et al. (2014) Vegetarian diets in the Adventist Health Study 2: a review of initial published findings. Am J Clin Nutr. 100(1): 353S–358S