What Is Glycogen, and Why Is It Essential for Your Health?
Glycogen is a form of stored sugar or glucose that is formed by many linked glucose molecules. It is the primary source of energy, which the body stores in the liver and muscle cells.
There are two types of glycogens:
- Liver glycogen — which acts as the main storage source that maintains blood glucose homeostasis.
- Muscle glycogen — which provides energy to muscles during high-intensity exertion, such as resistance training.
Glucose is derived from carbs found in specific meals and beverages. If not used, the glucose is then stored in your muscles and liver as glycogen for later use through a process called glycogenesis or glycogen synthase.
This process usually occurs when the body has an excess of glucose, especially on a high-carbohydrate diet.
When the body needs energy again, glycogen and its storage form are broken down and converted back into glucose. Eating 8-12 g carbohydrates per kg of body weight is considered necessary to make enough glycogen for energy.
In the body, glycogen:
- Gives your body energy — glycogen offers a constant supply of energy for the neurons, ensures that the heart has adequate energy stores, and so on.
- Helps control blood sugar levels — the glycogen stores in your liver regulate your blood sugar levels.
- Helps to increase muscle mass — glycogen is one of the main sources of energy for the muscles during exercise, supporting active muscles, muscle recovery, and growth.
and discover how much weight you can lose with DoFasting!
What Is Glycogen Depletion?
The process through which the body’s glycogen content is reduced or exhausted is known as glycogen depletion. The amount of time it takes to deplete body stores of glycogen can vary depending on your diet, muscle mass, and the intensity and duration of the exercise.
Glycogen depletion can take anywhere from a few hours to a few days. This process can, however, be sped up by strenuous exercise or prolonged periods of fasting.
When glycogen stores are depleted, the body enters a fasting state and switches to a fat-burning mode, allowing for the benefits of fasting to be achieved.
Glycogen stored in the liver is released to restore blood glucose during intermittent fasting in a process known as glycogenolysis.
As the glycogen storage in the liver is depleted, stored adipose tissue triglycerides are released into the blood as fatty acids and glycerol, leading to significant changes in metabolism. This leads to lower blood sugar and insulin levels and the use of fat as an energy source, activating the fat-burning mode which, ultimately, helps to lose weight and body fat.
Additionally, when glycogen levels are depleted, the body reaches ketosis, the ultimate phase of intermittent fasting.
What is ketosis, and how glycogen depletion impacts it?
Ketosis is a metabolic state in which your body starts to burn fat for energy instead of glucose, which you get by eating enough carbohydrates. When your carb intake is low, or if you’re on a low-carb regime like the keto diet, stored glucose is depleted, leading to ketosis.
During this state, fat is broken down and ketone bodies are produced, becoming the primary source of energy for both the brain and body. Glycogen depletion can also induce ketosis as it exhausts the stored glucose in the liver and muscles.
Your body may go into ketosis after 12 hours of fasting. Intermittent fasting is closely related to ketosis as it can lead to this metabolic state and use ketones for fuel in a faster manner than, for example, a ketogenic diet. The main benefits of ketosis include:
- Weight loss boost
- Appetite suppression
- Improvements in certain neurologic conditions
- Type 2 diabetes management
- Heart disease risk reduction
- Metabolic syndrome risk reduction
You should still consult a medical professional to figure out if a ketogenic diet (low carbohydrate diet) or an intermittent fasting routine are appropriate for you.
Glycogen Depletion Benefits for Intermittent Fasting
Glycogen depletion can have a lot of health-related benefits for intermittent fasting:
- Improved insulin sensitivity — with low glycogen reserves, insulin has less resistance and can more efficiently transport glucose into cells, which can improve metabolic health by lowering insulin resistance.
- Weight loss — your body uses fat instead of glucose for energy, which can lead to weight loss.
- Increased cellular repair — glycogen depletion along with intermittent fasting can boost the production of human growth hormone or other molecules that are important for cellular repair.
Note that further human study is required to properly evaluate the potential benefits of glycogen depletion and intermittent fasting.
7 Ways To Deplete Glycogen Quickly
Here are 7 methods for quickly achieving the benefits of glycogen depletion:
1. Reduce your carb intake during your eating window
Glycogen is derived from carbohydrates. When you consume foods and beverages that contain additional carbohydrates, your body digests them and turns them into glucose, which results in replenishing glycogen. Cutting carbs will lead to your body using up its glycogen stores.
This can reduce the glycogen content in muscles and liver. To deplete glycogen stores, it is recommended to consume less than 50 grams of carbohydrates per day. Some examples of high-carb foods include:
- Breads, grains, and pasta
- Nuts and legumes
- Starchy vegetables
- Snack foods
To reduce your carb intake, avoid high-carb foods, and plan your meals ahead of time.
2. Avoid highly processed and sugary foods
Sugary and highly processed foods cause blood sugar spikes as the high concentration of free sugars they contain are quickly absorbed. Insulin is then released to control these sugar levels and promote the storage of glucose molecules as glycogen.
These types of foods are typically lacking in nutrients and fiber, which can lead to imbalances in sugar and insulin resistance, contributing to glycogen storage and metabolic issues. They also contain excess calories, which are of no help when you’re trying to lose weight.
Therefore, consuming these types of foods can interfere with glycogen depletion or make it more difficult to achieve. Examples of foods that should be avoided include:
- All foods that come in cans, boxes, wrappers, and other packaging, also known as processed foods.
- Sweets such as chocolate, ice cream, cookies, etc.
- Sweetened drinks like soda, fruit drinks, iced teas, etc.
- Fried fast foods such as french fries, mozzarella sticks, fried chicken, etc.
To achieve glycogen depletion, it is important to avoid these foods and incorporate more vegetables, high-fiber foods, lean protein foods, and healthy fats into your low-carb diet.
3. Add in healthy fats like MCTs
Swapping out saturated and trans fats for healthy ones can decrease insulin resistance which is important for efficient glycogen depletion. Moreover, adding healthy fats can promote your body to use fats as an energy source instead of glucose and can help deplete stored glycogen stores in the body.
MCT oils are highly useful since they are quickly absorbed and transformed into energy. As a result, they are less likely to be stored as fat in the body and can aid in the depletion of glycogen reserves.
Examples of healthy high-fat foods that should be added to your diet:
- Olive oil
- Ground flaxseed
- Omega-3-fortified foods
Aside from including healthy, high-fat foods in your diet, you can also add MCT oil to your morning cup of coffee or use it in your salad dressing, non-cooked foods, or smoothies.
and discover how much weight you can lose with DoFasting!
4. Moderate your protein intake
You might consume too much protein if you follow a low-carb diet. If this is the case, your body can use protein as an energy source rather than glycogen, making it more difficult to deplete total glycogen stores.
This is why moderating your protein intake can help decrease stored glycogen levels.
How much protein you should eat daily to keep your overall protein levels at a moderate level depends on your weight, age, and activity level. It can vary anywhere from 40 to 60 grams a day.
To ensure that your protein consumption is moderate, you can keep a food diary, prepare home-cooked meals, and stick to the daily protein limit.
5. You still need to consume enough calories during your eating window
Keeping track of your macronutrient consumption is essential for glycogen depletion as it allows you to monitor the quantities of protein, carbohydrates, and fat you consume, and adjust your diet accordingly.
However, limiting certain macros is not the same as limiting calories—you still need to eat enough calories per day to ensure that your body has an adequate amount of energy for proper functioning and to avoid feelings of weakness and fatigue.
The recommended daily calorie intake for women is 2,000 calories per day, and for men, it’s 2,500 calories per day. However, calorie intake should always be calculated individually.
To ensure that you’re getting enough calories, count up the calories per serving of all the foods you eat and then plan your meals accordingly. You can also use an app for calorie tracking, such as DoFasting, which can help you keep an eye on this and many other metrics necessary for weight loss.
6. Increase the intensity of your exercise
High-intensity exercise depletes glycogen stores more quickly because it requires a lot of energy, causing the body to burn glycogen reserves faster. During exercise, glycogen is converted back to glucose and used as an energy source.
The longer and the more intense the activity, the faster the overall depletion of glycogen reserves takes place. The most effective exercises can include HIIT workouts, intense cardio, heavy-weight training, running, or cycling.
7. Choose the right type of fasting
Intermittent fasting has various types you can choose from, ranging from a 12-hour fast to a 36-hour one. Longer fasts may be better for glycogen depletion than shorter ones, but if this is your first time following a time-restricted eating pattern, it could be wise to start with the easiest methods.
The liver stores the most glycogen and plays the most important role in maintaining blood glucose levels during the first 24 hours of a fast. By around 24 hours of fasting, glycogen stores should be depleted. Nonetheless, an 18-hour fast might also have a similar effect.
If you’re unsure what kind of fast could be better for your needs, the DoFasting app can guide you with just a few questions. If the 24-hour routine seems too difficult at first, you can start with an easier plan and gradually work your way up over time. The app will keep track of your fasts and provide personalized advice on how to achieve the best results.
Glycogen Depletion Can Cause Unpleasant Side Effects – Here’s How To Reduce Them
Even though glycogen depletion can have promising health benefits for intermittent fasting, it can also cause unpleasant side effects in some people. This might be due to your body not having enough energy to function properly.
The possible side effects of glycogen depletion might include the following:
- Fatigue and low energy levels — glucose and the consumption of carbohydrates are related to high energy levels, and glycogen depletion can lead to low energy levels. The process can also lower blood sugar levels, which can result in fatigue.
- An initial drop in exercise performance — during high-intensity activity, glycogen is the main source of fuel for muscles. When muscle glycogen stores are depleted, muscles are unable to produce enough energy, which results in a temporary drop in exercise performance during your training sessions.
- Brain fog — glycogen can also be stored in the brain, where it becomes a critical source of energy for brain activity. In other words, the brain relies on glucose, which is derived from glycogen.
- Headaches — reduced blood glucose levels can trigger headaches and even worsen migraine attacks.
To minimize these adverse effects, stay hydrated, avoid strenuous exercise, and consume carbs during your eating window. Consult a medical professional and shorten your fasting windows or discontinue the keto diet if needed.
and discover how much weight you can lose with DoFasting!
How To Deplete Glycogen Stores Quickly: Key Takeaways
Glycogen is a store form of glucose. When the body doesn’t need glucose for energy, it stores it in the liver and muscles in this form.
The process in which the glycogen stores are reduced is referred to as glycogen depletion. Depleted glycogen can have beneficial effects for intermittent fasting that include improved insulin sensitivity, weight loss, and increased cellular repair.
You can help your body deplete these stores by improving your diet, trying high intensity exercises, or by intermittent fasting.
However, the process can have certain risks. Consult with your doctor if you feel more tired than usual, headaches, or brain fog.
This is an evidence-based article that includes scientific citations. DoFasting’s professional writers and editors prepared the content, which a team of medical experts verified to be accurate.