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By Nick Hall
This article looks at two hormones that have a profound influence on weight loss. Those hormones are Insulin and Leptin. We also discuss our stress hormone Cortisol and how elevated Cortisol levels can cause you to gain weight.
What is Insulin?
Insulin is a hormone that is secreted by the pancreas. When a meal or calorie containing drink is consumed, the contents of the food or drink is digested and released into the blood stream as glucose. As blood glucose levels rise, insulin is released. Insulin carries blood sugar to the different cells of your body and allows blood glucose or blood sugar to enter the cells. It is insulin’s job to help lower blood sugar levels after a meal.
The higher the levels of sugar in your blood, the more insulin needs to be secreted by the pancreas in order to lower blood sugar levels. The cells of our muscles and organs are only able to hold so much blood sugar. Once they are full, any excess sugar in the blood that is not utilised will be stored as fat. Fat cells on the other hand have no limits on how much energy they can store. If blood sugar levels are high, body fat will not be utilised.
Blood Sugar and Insulin Spikes
Depending on what you eat or drink determines on how quickly blood sugar increases. If blood sugar levels rise sharply, they can also fall quickly. When blood sugar levels are low, we become tired. We then crave the wrong type of foods in order to raise blood sugar levels. This can begin a cycle where blood sugar levels are constantly spiking and falling leading to more and more energy dense calories being consumed and stored as fat.
What causes sharp spikes in blood sugar and insulin? Carbohydrates, in particular, white carbohydrates such as bread, pasta, rice, refined sugars, soft drink, cakes, lollies and processed man made foods all contribute to a high spike in blood sugar levels. These foods provide quick release energy which is converted into blood sugar efficiently.
Constant spikes of blood sugar will result in high levels of insulin secretion. Over time, insulin resistance can occur. Insulin resistance is where the cells of your body aren’t listening to insulin. The cells of your body therefore aren’t receptive to insulin and allow blood sugar in. When insulin resistance occurs, blood sugar levels can remain dangerously high. Insulin resistance can then lead to type-2 diabetes.
Improving Insulin Sensitivity
Removing or reducing the above foods that cause sharp spikes in blood sugar will help to keep blood sugar levels more stable. Including slow release energy in the form of protein, high fibre plant food and omega 3 fatty acids will also help.
Dietary fibre helps slow the release of sugar into the blood. Carbohydrates from plant food contain only small amounts of energy however are high in essential nutrients. These should make up the majority of your carbohydrate intake each day. Insulin and blood sugar levels are a lot more stable when these types of carbohydrates are consumed.
A good source of protein and essential fats should also be consumed at each meal. This will help keep blood sugar and insulin levels more stable, give you the feeling of satiety and keep energy levels more constant. When blood sugar levels are more stable your cells become more sensitive to insulin. This will allow for greater utilisation of fat as energy.
Correct nutrient intake is discussed in more detail in the macro-nutrients presentation and also in the nutrition e-book
Improving Insulin Sensitivity through Exercise
Introducing the right type, amount and intensity of exercise can also help improve insulin sensitivity. Both resistance training and high intensity interval training can be incorporated. If the right intensity is used, i.e. maximum effort, this has been found result in better muscle glycogen utilisation.
More exercise is not better. In fact unless your nutrition intake is adequate to support the exercise you are doing, exercise will have little impact. Jogging or cycling at a moderate pace or lifting a weight that requires moderate effort will not have the desired effects on improving insulin sensitivity.
This is discussed in more detail in the exercise for weight loss presentation.
Our bodies have a master hormone called Leptin that is designed to regulate our hunger, energy intake and energy expenditure. Leptin also tells us if we have had enough to eat or whether we need to increase or decrease our level of fat utilisation. Leptin can also heighten our sensitivity to sweet foods.
Leptin is produced in our fat cells. The more fat we have, the more leptin is produced. As with insulin, we can become leptin resistant and our body doesn’t respond to leptin properly. When we are leptin resistant, our metabolism slows down, we lose the feeling of satiety and we lose our sensitivity to sweet foods meaning it takes more sweet food to satisfy us.
Improving Leptin Sensitivity
The strategy for improving leptin sensitivity is similar to improving insulin sensitivity. Reducing starchy foods such as potatoes, breads, cereals, grains and other processed foods can help improve you sensitivity to leptin. Including good sources of protein, plant food and omega 3 will also help improve leptin sensitivity. Also Brazil nuts, fish, avocado and olive oil can help.
What is Cortisol?
Cortisol is a stress hormone that is secreted by your adrenal glands. Under acute or short amounts of stress, cortisol is secreted and then shortly returns to normal levels. Cortisol also is your anti-inflammatory hormone.
How does Cortisol affect weight Loss?
Our bodies are geared for survival which dates back to when we were living outdoor, surviving cold winters and hunting for food. During periods of chronic stress, cortisol levels increase. Cortisol communicates to every cell in your body that there is no food. It sends a message to your metabolism to slow down, conserve energy and store fat. Your body will no longer be sensitive to insulin, your body will start to break down muscle and you will start to crave calorie dense foods.
Chronic long term stress can therefore result in weight gain or impair your ability to lose weight.
The different forms of stress could be workplace stress, emotional stress, financial stress, changing jobs, physical trauma, medical treatment or medication, dehydration, over training or nutritional famine. None of these forms of stress may be life threatening however your body may interpret this kind of stress as potentially threatening.
Over reliance on caffeine for energy can also cause chronic stress and promote fat storage. Caffeine tells your central nervous system and metabolism to go faster. Caffeine also activates your adrenal glands which produce adrenalin which is our flight or fight hormone. When adrenalin is released, blood sugar levels are elevated due to the release of stored glucose as our body is preparing to either flee or fight. If the blood sugar isn’t utilised as energy, it will be stored as fat.
Caffeine or the stress imposed on your body from large amounts caffeine can therefore result in fat storage. High amounts of caffeine can stress the digestive system and be toxic to the liver
There are a number of methods that can help reduce your stress or cortisol levels such as walking,
Meditation, yoga, Pilates, concentrated deep breathing, increased consumption of omega 3, green tea or green tea extract, dark chocolate or vitamin C. Cutting back on caffeine can also help.
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