Circadian fasting: what is it and how to practice it?

Circadian fasting has positive effects on metabolic health and body weight. How to put it into practice? Here we detail it.

Last update: 06 November, 2021

The circadian fast or circadian rhythm fasting refers to the decision to eat or not, according to the body’s internal clock. It is also known as “time-restricted early feeding” and its implementation is associated with several health benefits.

But what does the circadian rhythm refer to? The answer is simple. They are the physical, mental and behavioral changes that follow a 24-hour cycle. Therefore, it includes the light and dark signals.

Its importance lies in the fact that it affects health, since it intervenes in functions such as the release of hormones, eating habits, digestion, body temperature, metabolism, the wake / sleep cycle, among others. Do you want to know more about this form of fasting? Keep reading!

What is circadian fasting?

Before going into detail about circadian fasting, it is important to explain how the circadian cycle works. According to a post on National Institute of General Medical Sciences (NHI), the rhythmicity of this cycle is commanded by a central clock in the brain at the level of the hypothalamus. In particular, it responds to light and dark stimuli.

Right from there the biological clocks of all living beings are coordinated. To be more exact, these clocks are proteins that interact with cells throughout the body. Almost all tissues and organs contain them.

Now, as experts on the subject explain, the circadian system orchestrates metabolism in a 24-hour cycle, which results in rhythms in energy expenditure, appetite, insulin sensitivity and other metabolic processes.

Jakubowicz and his colleagues are convinced that eating in sync with circadian rhythms, especially early in the day, can help reduce body weight and improve metabolic health.

Circadian fasting is a form of intermittent fasting that involves eating or not, depending on the body’s biological clock.


About circadian fasting

Fasting from the circadian rhythm refers to the voluntary decision to eat or skip meals in accordance with the body’s internal clock. During the day signals are emitted that keep you alert, awake and active. Meanwhile, at night hormones regulate relaxation and sleep.

According to the magazine Nutrients, this form of fasting corresponds to a variation of intermittent fasting which involves having a longer daily fasting period. Preliminary studies report that this practice improves cardiometabolic health in rodents and humans.

Benefits of circadian fasting

According to Scheer and his research team, diet is a factor that synchronizes the circadian rhythm. Based on this, they have studied the best times to eat certain foods in order to improve health.

In this way, they observed that during sleep the body converts all components into energy and prepares to perform activities in hours of sunlight. Thus, keeping the eating plan aligned with the circadian rhythm provides the following benefits:

  • More energy level and less discomfort in the work day.
  • Decreased risk of metabolic disorders such as obesity, diabetes, and cardiovascular disease.
  • Better quality of sleep.
  • Prevention of digestive discomfort.
  • Decreased appetite, especially in cases of food anxiety.

It should be noted that food is considered a powerful synchronizer. However, for this to happen, it must be ingested at the right time, quantity and quality.

Circadian fasting supports the functioning of the metabolism and contributes to weight loss.


How to put this form of fasting into practice?

Before practicing circadian fasting or any form of intermittent fasting it is important to consult your doctor. It should not be overlooked that these types of techniques are not suitable for everyone. Once this is done, you have to find out about the function of the organs according to their internal clock.

Studies show that in each organ there are thousands of genes that are turned on or off always at the same time every day. In this regard, research has also determined that it is best to eat early to promote health and well-being.

Glucose is best controlled in the morning and tends to be worse at night. In addition, in the morning more calories are burned and food is better digested. Eating at inappropriate hours impairs digestion, as you have to work while you should be at rest.

So how do you practice circadian fasting? Here are some recommendations.

  • The last meal of the day should be done before the sun goes down.
  • You have to stop eating at least 12 hours a night. Counting starts from the last meal of the day.
  • In the 12-hour period it is valid to drink coffee, aromatic drinks and water, without additives such as milk or sugar.
  • The process must be repeated daily.
  • To lengthen the fasting time, the ideal is to advance dinner rather than postpone breakfast.

What is there to remember?

Circadian fasting has become a useful strategy for maintaining a healthy weight and improving health. Nevertheless, it should be practiced carefully, under professional supervision.

In the same way, it should be complemented with other healthy habits that also help to take care of the body. Such is the case of a daily rest routine, the practice of physical activity and a healthy and varied diet that provides all the nutrients.

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