Intermittent Fasting and Muscle Building: How it Works

Intermittent fasting has become increasingly popular in the past few years. Many people use intermittent fasting to manage body weight by switching between eating and fasting on a regular schedule. Studies suggest that following an intermittent fasting diet can prevent some forms of disease, in some cases even reverse the effects. Despite the popularity of intermittent fasting, many still have minimal understanding of the diet plan.

So, is intermittent fasting suitable for you? How do you choose which schedule to follow? What are the benefits? Read until the end to find out!


What is intermittent fasting?

Many diets focus on what to eat, but intermittent fasting is all about when you eat.

With intermittent fasting, you follow a schedule that allows you to eat at certain times. You can help your body burn fat by eating just one meal, each day, for a couple of days a week or by fasting for many hours.

It is much harder to carry out an intermittent diet plan in the modern-day compared to the past. The TV stays on for longer, usually correlating with snacking later. More people are working indoors and getting much less exercise due to video games and mobile phones. Less activity and higher calories increase the risk of obesity, heart disease, type 2 diabetes and other illnesses. 


How does it Work?

Intermittent fasting can be carried out in many ways, but they are all based on when you should eat and fast. A popular example is intermittent fasting 16/8. This means you only eat for eight hours each day and fast for the remaining sixteen hours. Another method is known as Eat Stop Eat, this involves a 24-hour fast from one dinner to the next day’s dinner. This can be done once or twice a week. There are many other methods for intermittent fasting.

Your body stores the sugars from food as glycogen, which is your first supply of energy. Therefore it will become depleted during a fasting period, meaning your body has to burn fat to provide energy. This process is known as intermittent metabolic switching (IMS). IMS rarely occurs for individuals who eat more than three meals a day and have low activity levels. This is because IMS only occurs when eating and exercise patterns cause the periodic depletion of glycogen stores (1).


Gaining Muscle

Fasting is a very effective way to stimulate Human Growth Hormone (HGH) naturally (2).

HGH promotes muscle, bone, and cartilage growth. Enabling you to get bigger, stronger muscles and reducing the effects of age-related bone and muscle loss.

Whilst fasting the release of growth hormones is maximised. This is due to your body being in a catabolic state, meaning the body is breaking down stored energy. When you break the fast after training, the body is sent into an anabolic state at the right time for targeted muscle growth.

Put simply, intermittent fasting is basically anabolic bio-hacking.

Intermittent fasting is becoming vital for increased growth hormone release as it naturally decreases as we age.


Lose Body Fat

When you eat before exercising, insulin is activated. Insulin is a storage hormone that is responsible for building up energy stores. Insulin also blocks the enzyme that breaks down stored body fat (3). 

This means that when insulin is produced and present in the bloodstream, fat loss cannot take place.

Also, due to food being consumed, the body readily uses the food in the bloodstream for energy when exercising. This means body fat stores are not being completed as there is no depletion of glycogen stores.

There are two scenarios where eating before a workout is necessary:

You train several times a day and need additional energy.

You want to add body fat as well as lean body mass.

Exercising regularly can also help your body reach ketosis. We cover everything you need to know about ketosis in a recent blog post. This enables you to burn fat efficiently when doing fasted workouts.


Intermittent Fasting Differs From Calorie Restriction

If muscle building is your main goal, intermittent fasting 16/8 does not require you to restrict your calories within the eating period. You just need to concentrate your daily calorie intake within the 8-hour eating period. For example, this can be done by having two larger meals instead of three normal meals. Allowing you to reach your calorie and protein intake goals for muscle building.

On the one hand, it means you can eat specifically after your workout. On the other hand, it means you may have to avoid eating before exercising if it is during the fasting period because even small meals raise insulin levels.

As stated earlier, intermittent fasting does not require a reduced calorie intake. It uses the timing of food consumption to optimise hormone levels to favour fat loss and muscle gain.



Physical performance- A recent study showed that young men, who fasted for 16 hours, maintained muscle mass whilst losing fat. Fasted training also helps optimise growth hormone release, further aiding muscle gain.

Tissue health– In animals, intermittent fasting reduced tissue damage in surgery and improved results.

Diabetes and obesity– When animals used intermittent fasting it prevented obesity. Also, six brief studies, involving obese adults, showed that intermittent fasting enabled body weight loss.

Heart health– Blood pressure and resting heart rates, among other heart-related measurements, had improved after using an intermittent fasting diet.


Final Thoughts

Intermittent fasting is a great diet plan to add to or create a healthy lifestyle. Some may use intermittent fasting to reduce the effects of chronic conditions, and others may use the diet for weight management. However, due to our individuality, intermittent fasting is not for everyone.

 Despite the benefits of intermittent fasting, some people should avoid the method: 

People with diabetes or blood sugar problems.

Women who are pregnant or breastfeeding.

Children and teens under age 18.