How to start intermittent fasting?

Fasting does not mean starving, eating less, or skipping meals. To start an intermittent fasting, it is enough to change the hours in which the intakes are made to activate a series of functions of the body with positive effects for health.

Written and verified by the nutritionist Anna Vilarrasa on 06 December, 2021.

Last update: December 06, 2021

Starting an intermittent fast can raise some fears. In recent years, it has become a fashionable topic and there is a lot of information about it about its benefits or its characteristics.

The following article aims to gather some of the basic information about what it is, how it works, who can try it, or what is the easiest way to get started. If you are curious or are already determined to try it, we encourage you to continue reading.

What is intermittent fasting?

Intermittent fasting is used to lose weight; however, it would have other health benefits.

Intermittent fasting is an eating pattern that alternates periods of eating with periods of fasting. It’s not about a diet per se, since it does not focus on what to eat, but on when.

Due to the voluntary participation of people, it cannot be confused with starvation. Done the right way, it doesn’t have to pose health problems or lack of nutrients.

Action mechanisms

The states of eating and fasting provoke a series of reactions in the organism. Knowing everything that happens in both cases allows to understand the process of operation and the possible benefits of the practice of intermittent fasting.

One of the most notable effects is regulated by insulin. After eating, it is elevated and allows cells to use available energy. Within hours (in what is known as a post-absorptive state) the insulin ranges are low. As a consequence, the body uses reserve energy sources to fulfill all its functions.

Too, more actions are activated at the cellular and molecular level. Another hormone that rises when you start a fast is growth hormone, thus stimulating muscle growth and fat loss (among other benefits).

Cells initiate cleaning and repair processes such as autophagy. This allows them to renew old proteins that have lost their functionality. In addition, some genes related to longevity and protection against disease are activated.



Possible benefits of starting an intermittent fasting

Many people try this way of eating with the goal of losing weight. Certainly, there is evidence that it may be a valid approach to control body weight, decrease fat accumulation, and maintain muscle mass. In addition, following an intermittent fast improves other health conditions:

  • Improvement of some markers such as glucose regulation, insulin sensitivity, blood pressure or heart rate.
  • Increases resistance to oxidative stress.
  • Inflammatory markers are reduced.
  • In case of type 2 diabetes or prediabetes, It can improve insulin resistance and lower glycosylated hemoglobin levels.
  • May improve cardiovascular health, since intermittent fasting acts positively on some of your risk factors (blood pressure, triglycerides, cholesterol or atherosclerosis).
  • In animals, cancer cells have been shown to inhibit growth and become more sensitive to chemotherapy. However, further studies are needed in this field.
  • It allows maintain or improve cognitive performance over the years.


Types of intermittent fasting

Intermittent fasting can be done in many ways. It is a flexible method that allows adaptation to the needs of each one. It usually ranges from a few hours to 1 or 2 days, although longer periods require professional monitoring.

Most programs include 24-hour fasting periods that are practiced 1 or 2 days a week. These are not consecutive and in them only liquid or a meal of 500 calories maximum is ingested.

Nevertheless, the most common way to start the fast is usually time-restricted feeding. This involves, for example, doing all the intakes within an 8-hour window and “resting” for the remaining 16 hours.

These periods can be 4, 6, 8 or 10 hours according to the convenience of each person. In addition, the time of day you eat (morning, afternoon or evening) can also be adapted.

Does it have contraindications or negative effects?

So far, some studies have determined that intermittent fasting may be helpful in managing metabolic disorders.

In general, healthy people can safely follow a fasting protocol, since changing the hours you eat does not have to be dangerous. It should be remembered that, in principle, it is not a restrictive program, but rather that it changes the periods in which the intakes are made.

A feeling of hunger, weakness or a lack of cognitive performance may appear temporarily. In principle, they are temporary situations of adaptation to the new eating pattern.

In case of insecurity or doubts about its suitability, it is preferable to visit a food specialist. What’s more, it is possible to start with the softer protocols and choose the type of intermittent fasting that best suits your life circumstances. That said, it is necessary to pay attention in some groups of people in whom fasting is not indicated.

Who Shouldn’t Start Intermittent Fasting

Despite its possible benefits and all the fasting modalities that exist, not everyone can practice periods of fasting. This is not indicated in the following situations:

  • Women who are pregnant or planning to be pregnant in a near period of time.
  • Nursing mothers.
  • Underweight people and those with eating disorders.
  • Adolescents under 18 years of age (they are still of a growing age and energy for optimal development may be lacking).

Also, intermittent fasting seems to work differently for women and men.. When the intake is very small or the fasts are very frequent, the secretion of some hormones can be altered. This dysfunction could be at the base of fertility problems, abnormalities in the menstrual period or bone problems.

Maybe for this reason it is best for women to start with gentler programs and stop any fasting immediately if amenorrhea or other side effects develop.

Consultation with the doctor is essential for those who follow a medication protocol. Also for those who suffer from diabetes, uric acid, kidney dysfunction, liver or cardiovascular diseases.

How to start an intermittent fast

You may be wondering at this point if intermittent fasting is good for you. Some people are drawn to trying this method and others are not. In the latter case nothing happens, then it is just one more way to take care of health and well-being.

There are other aspects as or more important as the quality of the diet and the foods that are eaten. Also other issues that do not have to do with food such as sleep quality, stress management or physical exercise.

On the other hand, if this type of program seduces you, its application is so simple that you can start tomorrow. An easy way to do this is to take advantage of the hours of fasting that you do during the night.

Thus, it is only necessary to delay breakfast a little or advance dinner to extend these hours. Depending on the schedule of each, it can be affordable to arrive at 12 or 14 hours without eating. Also this way of getting started allows you to check if your body adapts well and if this is a suitable method for you.

Once consolidated, you can try other modalities such as a 24-hour fast that can later be extended to two days a week. As there is no single model, you can also do it once or twice a month.

Intermittent fasting is one method with potential benefits, but not the only one

Are you tempted by the idea of ​​trying intermittent fasting? The good thing about this system is that you do not need to make a large investment or buy special products to start. You can also go back, if you encounter many difficulties or it does not suit you.

If it is done in the right way and starts little by little, it is not dangerous to health. You just have to check if it is a way of eating that suits your needs and consult a specialist for greater security.

In principle, fasting only modifies meal times. However, it is worth remembering that it is much better if your diet is based on fruits, vegetables, legumes, nuts, whole grains, olive oil and lean sources of protein.

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