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What happens to your body when you fast for 24 hours

what happens to your body when you fast for 24 hours

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What happens to your body when you fast for 24 hours?

Intermittent fasting is a diet that consists of not eating for a predetermined amount of time. The time frame can be anywhere from 16 hours to more than 24 hours.

16-hour fasting is the most practiced intermittent fasting type in the world. Although 16-hour fasting is famous I would talk about 24-hour fasting because the real magic happens after 24 hours.

If you start your intermittent fasting journey, you should start with a 16-hour fasting window. A 16-hour fasting window allows your body to adjust to intermittent fasting easier.

During a 24-hour fast, our bodies undergo various changes. We will talk about the things that happen in our bodies when we fast for 24 hours.

What happens after 12 hours of fasting?

When we fast for 12 hours the body will trigger a signal that will spike growth hormone. This hormone is also known as an anti-aging hormone.

what is growth hormone?

Growth hormone is a protein and hormone that is mostly secreted by the anterior pituitary gland. It has many functions such as regulation of growth, metabolism, and bone development. Growth hormone also plays a key role in sexual maturation and fertility.

Growth hormone is essential for children as well as adults to build bone mass which will help them to develop their height. However, people who have growth hormone deficiency or resistance suffer from stunted growth and decreased quality of life.

Growth hormone deficiency affects an estimated 1% of the general population but can be found in up to 20% of individuals with Turner syndrome (a genetic disorder characterized by incomplete ovarian function).

Some people take growth hormone from outside for optimal performance in the body. But intermittent is much safer to get the easily available growth hormone. Like intermittent fasting, exercise will also increase growth hormones.

What happens after 18 hours of fasting.

After 18 hours of fasting, you will develop a process called autophagy.

What is autophagy?

Autophagy is the process by which cells break down their own components in order to recycle them and use them in other ways.

Autophagy plays a key role in the regeneration of cells. This process is important for maintaining health and preventing disease.

Autophagy has been linked to everything from cancer, diabetes, aging, neurodegenerative diseases, and epilepsy to cardiovascular diseases, infectious diseases, inflammatory diseases, autoimmune disorders, obesity, brain injury, or stroke.

Any kind of cellular protein that is not used by the body is cleaned by autophagy. This process also renews the tissue.

Autophagy starts around after 18 hours of fasting and this process continues to grow over time when you prolong the fasting.


What happens after 24 hours of fasting

After 24 hours of fasting, the body starts to deplete the glycogen reserves.

What is glycogen?

Glycogen is a form of glucose that is stored in the muscles and liver for later use.

A molecule of glycogen consists of molecules of glucose bound to three molecules of trehalose, two molecules of maltose, and one molecule of inositol. Glycogen is converted into glucose when it is needed by the body and used in muscles and the liver in response to exercise or starvation.

Glycogen is also known as the “glucose reserve,” because it functions as a substrate for gluconeogenesis, which converts non-carbohydrate substrates such as lactate, pyruvate, glycerol, and alanine into glucose.

So after 24 hours of fasting the energy that is reserved in the liver and the muscles get exhausted.


The magic of ketones

When the body is out of all the reserved energy, it will start to use ketones.

What are ketones?

Ketones are molecules that are produced when the body breaks down fat for energy. Although the name sounds like it is related to keto, ketones are not associated with only low-carb diets. It can be achieved with intermittent fasting also

Ketones are broken down from fatty acids and turned into acetyl CoA through a process called beta-oxidation. Ketone bodies can then be used by other cells in the body as an alternative fuel source.

why ketones are good for your body?

Ketones are beneficial to the human body. They are produced when our body uses fat as a fuel source rather than glucose.

Ketosis is a metabolic state that occurs when there is a lack of glucose in the bloodstream, which is primarily due to fasting or carbohydrate restriction. Ketosis can also be achieved through an effort of the body to produce ketones from stored fat. When ketosis occurs, it leads to weight loss, increased energy levels, and better overall health overall.

Other things that happens after 24 hours of fasting

So after around 24 hours of fasting your body starts to use fat instead of glucose for energy.

Your hunger goes away

When you don’t eat for 24 hours, your body’s hunger hormones change and instead make a hormone called “ghrelin” that tells your brain that you’re not hungry.

When you stop eating, ghrelin levels go up and tell your brain that you’re not hungry. Ghrelin also makes your body feel less stressed because ghrelin helps regulate the production of cortisol.

Fasting provide more antioxidant

Ketones provide more antioxidants than carbs because they are an alternative energy source. Ketones are also easier to burn off in comparison to carbs which require oxygen for combustion.

Your inflammation starts to drop significantly

Inflammation like arthritis or an autoimmune condition starts to improve when your body is using this alternative energy source ketones.

Gut healing

When you fast for 24 hours your gut starts to heal itself because it is getting rest. Your body starts to produce more stem cells that help to heal your gut.

The heart improves

The human heart loves ketones more than glucose. The cardiovascular function gets improved after fasting for 24 hours significantly.

The brain starts to repair after 24 hours of fasting

The brain functions get improved after 24 hours of fasting. BDNF is a protein with an important role in the development and maintenance of the brain and in emotional and cognitive functioning. Fasting helps to repair the brain with the help of BDNF when we fast for 24 hours.



As you keep going on with the fasting, you will find more benefits. Please read the article How does intermittent fasting work to find out more about the subject.

When you finish your fast don’t eat anything that you like. Use healthy food that is good for breaking your fast. Please read the article best food for intermittent fasting.

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