You hit the gym most days and eat the right foods as often as possible, but the scales show your weight hasn't shifted - or worse, increased. So, what's the deal?
‘Insulin’ and ‘insulin resistance’ are words that are often thrown around when it comes to various aspects of our health, such as blood glucose regulation or type 1 or type 2 diabetes. Or perhaps you’ve heard them linked to your ability to lose body fat. To appreciate what we can do to support a healthy insulin response, we must first understand exactly what insulin is and what it is designed to do.
What is insulin?
Insulin is made by the pancreas, and it is a type of growth hormone, hence its capacity to drive fat storage. We make insulin in response to an increase in our blood glucose (sugar) levels, which occurs when we eat or as part of the stress response. Insulin allows the glucose to move from the blood into our cells where it can be used for energy, so it is key for regulating our blood glucose levels.
Carbohydrates elicit the largest production of insulin, while protein drives a smaller amount of insulin release, which is usually offset by another hormone that protein elicits called glucagon, which acts in the opposite way to insulin. Consuming dietary fats does not drive an insulin response.
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How does it work?
It is big surges of insulin - on and off over the day, or constantly high circulating insulin - that cause the problem when it comes to fat burning. While this often comes down to our food choices, our blood glucose regulation can be influenced by other lifestyle factors as well, such as how much physical activity we do and what our stress levels are like.
Over time, our cells can stop responding appropriately to insulin and so our body has to make larger amounts of insulin to keep our blood glucose levels in check—this is known as ‘insulin resistance’. Meanwhile, the larger amounts of circulating insulin also signal to the body to store more body fat.
Our biochemistry has what are called built-in negative feedback mechanisms, which are supposed to stop us from gaining too much weight. In some people, this is not working efficiently or, if it is, it is being ignored biochemically. Scientists have been exploring what has the ability to block the signals telling our body to eat less and move more. Something is getting in the way, and research indicates that insulin can be involved in this block.
The role of leptin
If insulin levels are high, another hormone called leptin is supposed to kick in and tell your brain that you’ve eaten, thereby reducing appetite. Leptin is produced by fat cells, and circulates through the blood, binding to receptors in the hypothalamus, the area of the brain that controls energy balance.
So, leptin is supposed to turn off the desire to eat. In addition to this, it also triggers the involvement of the autonomic nervous system (ANS) — various parts of which either promote or block fat burning. Research has shown that insulin interferes with leptin’s ability to signal to the brain to stop eating. However, studies in which leptin was given to obese people under the hypothesis that it would shut off appetite have usually found that it is not the miracle pill it was anticipated to be, and here’s why. It appears that insulin can play a role in stopping your brain from being able to “see” leptin, which leaves leptin lousy at down-regulating appetite. The key here is that insulin must first come down for appetite to decrease, especially the desire for carbohydrates, and for weight loss to be sustained.
If you feel that high levels of insulin may be key to your efficient body fat utilisation, here are a few ways to help keep your insulin levels on track.
4 ways to keep your insulin levels in check
Exercise increases the sensitivity of skeletal muscle to insulin. When this happens, your pancreas can make less insulin, so your levels of insulin will decrease. And the result will be less insulin required in your blood to move glucose into your cells, meaning less fat storage signalling.
Many people ask me what the best type of exercise is. The reality is, the best type is going to be the type you can sustain. If you force yourself to do something you really dislike, it’s going to be very difficult to sustain this so the benefits are more likely to be short-lived. Remember too, that the more muscle mass you have, the greater your storage capacity for glucose (we store it as glycogen) and that too, usually means less fat storage being signalled.
2. Consider your caffeine intake
If you love your coffee, you’ll probably want to stop reading here…
Caffeine stimulates the production of your stress hormone, adrenaline. When adrenaline is released, your blood glucose elevates to provide more energy—and given that we (thankfully) aren’t constantly escaping from danger and burning the glucose that has been mobilised (we tend to be sitting at our computer drinking our coffee) - this then triggers the production of insulin to lower your blood glucose level.
You want to maintain fairly consistent blood sugar levels throughout the day. If you’re constantly getting highs and lows it can wreak havoc on your health and energy, your body’s response to insulin, not to mention driving sugar cravings. Try to stick to one coffee per day, or do a trial for four weeks without it and see if this makes a difference for you.
3. Focus on eating more whole, real food
When you focus on eating more whole, real food what you’re also doing is reducing the amount of processed food in your way of eating—usually without really realising it. It’s the reliance on processed and packaged foods that is problematic for your health and, especially if you consume significant quantities of highly refined carbohydrates long term, it can mess with your body’s ability to remain insulin sensitive.
Including a combination of fat, protein, carbs and fibre from whole foods in your meals will also help to keep your blood glucose levels steadier (preventing a spike which would trigger a bigger release of insulin), which will also help to keep you feeling satiated and energised for longer.
4. Make sleep a priority
Getting enough restorative sleep is absolutely essential to our health. When we are lacking sleep, this can interfere with proper blood glucose regulation as well as our appetite regulation, leading to increases in cravings for poorer quality foods. Adults generally need 7-9 hours of sleep per night so if you’re consistently getting less than this, consider making this a higher priority. Making nourishing food choices and moving your body regularly, as well as reducing your need for caffeine to boost your energy, will all be easier to achieve when you’re well rested.
Dr Libby is a nutritional biochemist, author and speaker. Find her on Instagram @drlibby.
Here are some simple tips for weight loss including exercise, portion control and healthy eating....
Here are some simple tips for weight loss including exercise, portion control and healthy eating.
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