Fasting: what it is, what it is for and how to do it, benefits, consequences

Fasting: what it is, what it is for and how to do it, benefits, consequences

Fasting is a period of abstinence from food. Always present in different cultures and religions, it can be of different types: intermittent, every other day, for more or less short periods. Intermittent fasting consists in refraining from consuming food only at certain times of the day. At a molecular level, when we enter a period of fasting, the body perceives the low blood sugar and tries to respond by activating the sense of hunger.

However, lack of nutrition causes the body to start breaking down lipid molecules (fats) in the body in order to ensure survival.

In addition to this we can also find other positive effects of fasting, such as cell regeneration and the reduction of the production of free radicals which, according to some studies, would help improve the health of our body.

What is fasting: definition and types

According to history, fasting was introduced into Christianity in 325 at the Council of Nicaea. It was originally intended as a period of self-discipline aimed at spiritual purification. But what are the nutritional benefits of fasting and what can we do to take full advantage of them?

During this regimen all foods of animal origin are excluded from the diet. But to maintain a balanced diet they must be replaced with suitable products rich in nutrients, such as a greater quantity of legumes (including soy and its derivatives), vegetables, fruit, nuts and seeds, vegetable fats, herbs and spices.

Overly processed foods and saturated fats should be avoided as much as possible, which are found in many foods used as substitutes during some types of diets such as:

  • Margarine.
  • Pastries.
  • Vegetable pate, etc.

Intermittent fasting

Intermittent fasting is an eating pattern in which people limit their food intake to certain times of day. Some research suggests that it may have major benefits for the body beyond weight loss, such as improving brain and heart health. Intermittent fasting (IF) is currently one of the most popular health and fitness trends in the world.

People use it to lose weight, improve their health and simplify their lifestyle. Many studies show that it can have powerful effects on the body and brain and may even help you live longer.

Several methods

There are several ways to practice intermittent fasting, each of which involves dividing the day or week into periods of eating and fasting.

During periods of fasting, little or nothing is eaten. Some of the more popular methods include:

  • 16/8 method: also called the Leangains protocol, it involves skipping breakfast and limiting the daily eating period to 8 hours, for example from 1pm to 9pm; then fasting is contemplated for 16 hours.
  • Eat-Stop-Eat: This method involves fasting for 24 hours, once or twice a week, such as not eating from dinner one day until dinner the next day.
  • 5:2 diet: with this method, a calorie restriction of only 500-600 calories is implemented on two non-consecutive days of the week, but eating normally on the other 5 days.

By reducing your calorie intake, all of these methods will naturally cause weight loss as long as you don’t compensate by eating much more during your normal eating periods.

Many people find the 16/8 method to be the simplest, most sustainable, and easiest to stick to. For this reason it has also become the most popular.

If you are interested in the topic, discover our study on intermittent fasting.

Fasting: how it affects cells and hormones

When we fast, several things happen in the body on a cellular and molecular level. For example, our body regulates hormone levels to make stored body fat more accessible. Cells also initiate important repair processes and modify the expression of genes.

Some additional changes that occur in the body when you abstain from food include:

Human Growth Hormone (HGH)

Growth hormone levels skyrocket, increasing up to 5 times. This is crucial for fat loss and muscle gain, just to name a few.


Insulin sensitivity improves and insulin levels drop dramatically. Lower insulin levels automatically make stored body fat more accessible.

Cell phone repair

In fasting, cells initiate cellular repair processes. This includes autophagy, i.e. the process in which cells digest and remove old and dysfunctional proteins that accumulate within them as a result of metabolism.

Gene expression

There are changes in gene function related to longevity and protection against disease.

These changes in hormone levels, cell function and gene expression are responsible for the health benefits of intermittent fasting.

Types of Fasting: How Do They Work?

I fast every other day

It is sometimes called a “complete” alternate day fast because the time you do not eat food lasts a full 24 hours. The regimen includes one or more “party” days where you can eat as you please.

Although the studies are very limited, the findings suggest that alternate day fasting can lead to weight loss and improve health. However it could be quite difficult to maintain it in the long run.

Modified fasting

This type of regimen allows you to eat 20% to 25% of your normal daily energy requirement on scheduled fasting days.

A popular version, the 5:2 diet, calls for 2 days a week (non-consecutive) of 24-hour “fasting,” with the exception of one very light meal. On the other 5 days of the week you can eat what you prefer.

Short-term fasting

Our body is basically used to alternate periods of weight loss with periods of growth of fat mass. This was developed thanks to the habits of primitive man, who found himself alternating periods of feeding with moments of scarcity of food.

For this reason many studies suggest that a short-term fast (a few hours a day) would bring many benefits including cell regeneration.

Long-lasting fasting

The human body necessarily needs food to nourish its cells. This is done by converting any type of food ingested into glucose. When the amount of sugar in the blood decreases (fasting), the body mobilizes its reserves to keep the organs alive, converting fat into sugar.

But not only that, together with the beginning of a state of ketosis, a process of cellular regeneration would also seem to begin. In the long run, however, the state of ketosis can become harmful.

In fact, when present in excessive quantities, ketone bodies are toxic. Another secondary effect will be the lack of vitamins and minerals as well as excessive weight loss.

Benefits of fasting for the body

The benefits of fasting are not only spiritual but can also include the body and mind if the rule is strictly followed.

Whether a person is religious or not, fasting is something that exists in every culture and religion and is even mentioned in history.

It doesn’t matter if you choose to abstain from food for religious or health reasons (there are some fasting diets with longer or shorter periods), the thing to remember is that fasting can be a great way to rejuvenate your body. , mind and soul.

Helps restore balance to the digestive system

Not many people know this, but fasting can be one way to help your body. Like musical instruments in fact, it is possible to “tune” your digestive system. According to endocrinologists, for example, during fasting insulin secretion is suppressed and the craving for sugar is reduced (and perhaps we also realize that we can live without it).

What actually happens is that the body eventually starts using the stored sugar (glycogen), so less insulin is needed to help the body get the needed energy from food. This gives the pancreas a little break.

Other research shows that fasting can also lower high cholesterol. Attention, fasting doesn’t just mean eating foods that don’t contain meat and derivatives, but turning your attention to simplicity, to foods that are as natural as possible and less processed.

Eating french fries, white bread, and plant-based meat substitutes every day is not considered a good eating habit if you intend to maintain a fast for a healthy lifestyle.

To physically feel the benefits of fasting, it is recommended that during this time you focus on fresh fruits and vegetables, cooked legumes, whole grains, along with moderate amounts of nuts, seeds, and vegetable oil.

It is also important not to forget to drink water and herbal teas to keep the body hydrated and for optimal digestion.

Reduction of free radicals

Some scientists of the “National Institute on Aging”, located in America, have reported that periods of fasting can reduce the amount of free radicals (their action can promote the onset of cancer).

Indeed, according to the researchers, these free radicals attack proteins, DNA, cell nuclei and cell membranes and can damage different molecules in cells.

Even reducing your calorie intake is…