Like leptin and ghrelin, insulin and glucagon are two sides of the same coin as far as hormonal balance goes. They work together to ensure that the body maintains a tight regulation within the healthy range of blood sugar – or at least they should! They operate via a negative feedback loop, wherein one event triggers another, which triggers another and so on.
Insulin is a hormone that regulates blood sugar. It is released by the beta cells in the pancreas in response to a meal. When you eat your blood glucose levels rise, and depending on WHAT you have eaten will determine how high the levels rise, and how quickly. Our entire body should have approximately 5g of glucose in the bloodstream at any one time – any more is toxic – and that’s about 1tsp! So to keep the level within range insulin is released to remove the glucose from the blood and deposit it around the body as required.
The first port of call will be your body’s cells, for immediate energy, then any excess will go to the liver and muscles to be stored as glycogen, which will be converted back to glucose as needed when the cells run out. But the liver and muscles have only a limited storage capacity, so any extra glucose is then sent to adipose tissue to be stored as fat. This is often then not accessed for energy, as the body demands more glucose, and this is what causes weight gain.
What foods cause higher insulin levels?
Foods are divided into macronutrient groups:
Each of these can create a rise in insulin, but to very different levels.
If your diet is high in carbohydrates, this will spike your insulin more because as soon as carbohydrates enter the body they break down into glucose. Your body doesn’t know whether you ate a bowl of pasta, a bowl of table sugar, three pieces of bread or chocolate cake – it is all the same once you have eaten it. After eating carbohydrates blood sugar (glucose) rises very quickly and insulin is released quickly to deal with it. The more glucose you have eaten, the more insulin you will produce. If you continue to eat regularly throughout the day – and particularly a carb heavy diet – then insulin will be constantly being released into the body in an attempt to push the glucose into your already full cells. The only place for the glucose to go in this scenario is into the fat cells.
Protein, on the otherhand whilst raising insulin, it does so to a lesser degree – and particularly when eaten within a low carb or ketogenic protocol.
Fats raise insulin levels the least, but they do affect it as they are composed of three fatty acids (triglycerides) which are attached to a glycerol backbone. It is the glycerol element that will contribute to raising insulin to some degree.
Simplistically, glucagon controls the production and release of glucose from the liver to the blood and insulin controls blood glucose by directing the liver to remove glucose from the blood, directing it to cells for energy, converting some to glycogen to be stored in the liver and muscles for future energy and any excess will be stored in adipose (fat) tissue. When insulin is low glucagon is high and vice versa.
What is hyperinsulinemia?
This refers to chronically elevated insulin levels. When this occurs conditions such as type 2 diabetes and obesity start to appear. Eating (and overeating especially) ultra processed foods, added sugars and refined carbohydrates can lead to hyperinsulinemia.
What is insulin resistance?
This occurs when the body’s cells stop responding to insulin. When blood sugar levels are high and the pancreas releases insulin to bring it back under control, this can be a difficult, and vicious cycle when an individual is continually eating foods that cause their blood sugar to rise throughout the day. This can result in hyperinsulinemia (see above) where the pancreas is constantly releasing insulin in an effort to control the rising blood sugar. Over time the body’s cells can stop responding to the insulin, becoming resistant to the message that it is trying to send. This results in both a rise in insulin levels and blood sugar and is potentially very dangerous. Type 2 diabetes is a direct result of this situation. Eventually the pancreas itself may become overwhelmed and damaged, leading to a decrease in insulin production and the inevitable need for exogenous insulin to be administered.
Causes of insulin resistance:
- High amounts of fat in the blood – this occurs with a high carbohydrate diet, not a high fat diet, as excess carbohydrates are stored in the fat cells. Obesity, overeating and weight gain are all strongly correlated with insulin resistance. Carbohydrate restriction has been shown to reduce symptoms of metabolic syndrome, including hyperinsulinemia and insulin resistance.
- Visceral fat – this is the fat that accumulates around the organs. Whilst we need a little, to protect the organs, too much is dangerous and leads to conditions such as non-alcoholic fatty liver disease (NAFLD) and insulin resistance.
- Inflammation – this can occur due to increased oxidative stress which is diet and lifestyle related; overeating, eating ultra processed foods, being sedentary…
- Fructose – high levels of fructose, particularly from added sugars has been correlated with insulin resistance. Eating large amounts of fruit every day may not be as “healthy” as we are led to believe, and drinking fruit juice is on par with drinking soda.
- Lack of physical activity – leading a sedentary lifestyle causes insulin resistance, whilst being physically active increases insulin sensitivity.
- Gut health – whilst this is still in its infancy there is evidence to suggest that gut dysbiosis (imbalance in microbiota) can result in inflammation, which can drive insulin resistance. Conditions such as gut permeability (leaky gut) can result in systemic inflammation, again driving other conditions, which may result in insulin resistance.
How to find out if you are at risk:
Whilst a common test for type 2 diabetes is a fasting glucose test, a better marker for insulin resistance is a fasting insulin test as high fasting insulin levels will determine whether you are likely to be insulin resistant – and will better predict a state of pre-diabetes. If you are overweight or obese (particularly if you have a large amount of belly fat), you are at higher risk of being insulin resistant. Low HDL cholesterol and high blood triglycerides are also another marker for insulin resistance.
How to improve your risk factors for insulin resistance:
- Reduce your carbohydrate intake – particularly refined carbohydrates such as bread, pasta, cereal, flour etc… A low carb/high fat diet has been shown to improve insulin resistance and hyperinsulinemia.
- Avoid added sugars – this can also include eating large quantities of fruit daily, particularly high sugar fruits such as pineapples, mangoes etc… and avoid dried fruit completely as these are easy to overeat and have a much higher percentage of fructose.
- Eat more protein – although all foods raise insulin levels, protein and fat do so on a much lower level, and the effect lasts for a much smaller amount of time. Whereas carbohydrates will raise insulin for a period of approx. 4 hours, the level to which protein raises insulin lasts for approx. 1 hour. Including more protein in your diet leads to long term results such as fat loss, and a reduction in insulin resistance.
- Eat more healthy fats – but be sure to lower carbohydrates as you do so. Eating more fat can help to reduce insulin levels.
- Exercise regularly – Studies indicate that regular physical activity helps to promote insulin sensitivity, and reduction in total and intra-abdominal body fat amongst overweight post-menopausal women.
Glucagon is an amino acid peptide that is released by the alpha cells within the pancreas. It is released in response to low blood sugar levels, stimulating both glucoglycolysis (changing stored glycogen back into glucose) and gluconeogenesis (creation of new glucose in the liver from protein). It also stimulates the breakdown of stored body fat (lipolysis) and stimulates ketone production in the liver as an alternative form of energy. It is also involved in protein metabolism and so, in these different ways, the primary role of glucagon is to ensure that there is sufficient energy supplied to all the organs of the body.
Glucagon works in opposition to insulin, so when insulin levels are high, glucagon levels are low, meaning that alternative fuels, such as fat oxidation is effectively turned off – this means that the body is using glucose for energy, with very little coming from fat stores. Where insulin lowers elevated blood sugar, glucagon raises it. When the levels of glucose in the bloodstream are low, glucagon ensures that it does not reach dangerously low levels. Messages are sent to the liver to create new glucose from amino acids from the protein we ingest – gluconeogenesis.
Approximately four to six hours after eating (depending on what you have eaten and the amount of glucose that it converts to), blood glucose levels decrease, lowering insulin and stimulating glucagon to convert any stored glycogen in the liver and muscles back into glucose for energy. When glycogen levels are depleted, lipolysis is then triggered, releasing stored body fat into the system for energy use. When an individual is eating a low carb or ketogenic diet, or fasting, then the liver will be stimulated to produce ketones as an alternative fuel supply, as well as the now available fatty acids that have been released into the blood stream, or have come in via dietary fats. This continual feedback loop ensures that the body has a continual supply of energy and prevents the blood sugar from dipping dangerously low.
Insulin can send a strong message to the body to store fat. Excess insulin stimulates the kidneys to retain salt and fluid, stimulates the production of cholesterol and increases triglyceride (fat) production. Glucagon does the reverse, sending a signal to the kidneys to release excess salt and fluid and signalling to the liver to slow down the production of cholesterol and triglycerides. Blood pressure drops, due to the artery walls relaxing and fat cells are stimulated to release stored fat to be burned for energy. Studies have shown that glucagon is effective at reducing appetite and stimulating weight loss.
As previously mentioned, glucagon aids in the process of converting protein to glucose when necessary (gluconeogenesis), and also fat to some degree as fat contains a glycerol backbone to which the triglycerides (three fatty acids) are attached. It also aids in the production of ketones, which are made in the liver and are an alternative fuel for the body to burn for energy. Dietary fat can also be converted into ketones when glucose and insulin levels are low. By these mechanisms, glucagon effectively shifts the body into a fat burning metabolism; releasing fat from storage and into the body’s tissues for energy. The more we encourage glucagon to be present in our body, as opposed to insulin, the better and more efficient our metabolic health will be. We cannot have one or the other, but we can strive to have dominance of one over the other. Both are essential for a healthy, normal functioning body.
Whilst insulin is not inherently “bad”, and is completely necessary in the overall processing of food within our body, it can become a negative influence if we are producing too much, or become resistant to the messages it is trying to send. The benefits of glucagon as a potential treatment for metabolic syndrome are being recognised as an alternative treatment to insulin: “the possibility that glucagon may also have benefits in the treatment of metabolic disease has received little or no attention. However, new studies that describe novel preclinical applications of glucagon, either alone or in concert with glucagon-like peptide 1 (GLP-1) agonism, have revealed the prospect of harnessing the benefits of glucagon action for the treatment of the metabolic syndrome”.
How can you keep insulin low and glucagon high?
When insulin levels are high they overwhelm the system and suppress the actions of glucagon. As food is the primary signal controlling both insulin and glucagon, it is essential to create a nutritional structure that minimises the release of insulin and maximises the effect of glucagon. In this way, blood sugar can be controlled more effectively, and healthily, at the low end by glucagon by implementation of a low carbohydrate diet and/or intermittent fasting. Trying to control blood sugar at the high end via insulin is really getting things back to front. And this is when bad things can happen such as the development of metabolic syndrome and conditions such as type 2 diabetes.
Nutritional interventions such as intermittent fasting and/or a low carb, or ketogenic diet have proved to be very effective in reducing insulin levels and promoting a fat burning metabolism. During periods of fasting insulin is low because there is no food for the body to deal with, which allows glucagon to perform all its functions without interruption. The same is true of a low carbohydrate or ketogenic diet, as these both promote low glucose levels in the blood and therefore keep insulin levels low. Glucagon is then available to enable fat and ketones to be burned for fuel, thereby helping to promote weight loss and provide more energy, whilst keeping hunger at bay. A low carbohydrate diet has proved to be both very effective and sustainable at achieving hormonal balance between insulin and glucagon.
To find out more about how you can transition to a fat burning metabolism, and balance your hormones click here.