What are the psychological effects of intermittent fasting?

Intermittent fasting is a dietary protocol that involves total or partial abstinence from eating for a specific period of time (for example, for 12 hours a day) and ingesting necessary foods and nutrients for the rest of the day, when you are not fasting. We are talking about a practice that has gained notoriety in recent years, with its lights and shadows.

Among the various psychological effects of intermittent fasting, it should be noted that these could be both positive and harmful, so it would be advisable to consult professionals before putting it into practice and, in any case, it should be done. do it gradually and do not start abruptly by practicing a prolonged fast.

In this article we will explain in more detail What are the different psychological effects of intermittent fasting?but let’s first see what intermittent fasting actually is and what the most popular types of fasting are.

    What is intermittent fasting?

    Intermittent fasting is a dietary protocol that involves abstaining from food partially or completely for a specific period of time and ingesting the foods and nutrients necessary to maintain a balance during the period of time when fasting is not practiced. (for example, doing intermittent fasting for 16 hours a day, so that the necessary food is consumed in 2 or 3 meals during the remaining 8 hours of the day you are not fasting).

    It should be noted that this practice must be supervised by a professional expert on the subject so that it is not harmful and it is also important to say that the practice of intermittent fasting is not a diet but an eating protocol, which means that it is about the way including meal times and there is no set plan that tells what to eat as is usually the case with diets.

    However, it is also important to know that when practicing intermittent fasting, it is very important that during the eating period you try to perform a balanced diet with all the necessary nutrientsmeaning that fasting should not be used as an excuse to binge and eat uncontrollably processed foods high in sugar and saturated fat, as this will negate the possible benefits of intermittent fasting.

    On the other hand, there are several types of intermittent fasting, among which we must highlight those that we will briefly explain below.

    1. Intermittent 12 hour fasting (12/12)

    This type of intermittent fasting is the shortest and therefore the simplest, so perhaps it would be the most recommended. In any case, at the start of the practice of intermittent fasting, you must first start with this type of fast and then gradually move towards the practice of a longer fast, always under control and supervision.

    In addition, it would be a fairly accessible fast, since if we count the approximately 8 hours that we sleep and the 3 hour period that should pass between dinner and bedtime, we will have already completed 11 hours of fasting, because simply waiting for breakfast 1 hour more when you get up would have done a 12 hour fast if too much effort.

      2. Intermittent fasting for 16 hours (16/8)

      This is the most popular type of intermittent fasting involves fasting for 16 hours, so that 2 or even 3 meals are usually distributed over an 8-hour period. Those who practice it usually skip breakfast and wait to eat for the first time at lunchtime (e.g. fast from 9 p.m., dinner time, until 12 p.m., lunch).

      3. Intermittent fasting for 20 hours (20/4)

      We would already be talking here about a fairly long fast which requires a process of prior adaptation and also greater control and monitoring. In this case, we would help 20 hours a day, so we only eat for the remaining 4 hoursbeing the most common to have 2 meals during this period (for example, fasting from 9 p.m., after dinner, until 5 p.m. the next day, having a meal at 5 p.m. and another at 8 p.m.).

      4. OMAD Meal Plan or 23-Hour Fast (23/1)

      This type of intermittent fasting would be the longest among the best known, also known as the OMAD (“One Meal A Day”) diet, which, as the acronym of its own number in English indicates, essentially consists of in have only one meal a day. Here we would already be talking about a rather expensive type of fasting, so it would not be very advisable to practice it for a long time, just like the 20 hour one, because it could be harmful.

      Regarding the practice of intermittent fasting, it should be noted that the protocols with the most scientific evidence regarding their long-term benefits would be the 12-hour and 16-hour protocols, in addition to being the easiest to follow. and less effective. restrictive. However, it is always recommended to consult a professional first because it could be very harmful for people vulnerable to its effects (eg people with diabetes, hypertension, certain eating disorders, etc.).

        The possible psychological benefits of intermittent fasting

        There are many testimonials, as well as a few studies, that claim the existence of various benefits on the practice of intermittent fasting; however, more research is still needed in this regard, especially with humans, so that we can make more robust statements.

        Next, we will briefly explain the main psychological effects of intermittent fasting that are beneficial, according to various investigations conducted from this eating protocol.

        1. Increased self-control over food

        One of the main psychological effects that the practice of intermittent fasting could bring would be an increase in self-control, since with this protocol one of the possible objectives sought is establishing greater self-control over hunger and satiety, thus regulating the hormones responsible for it (ghrelin and leptin). In addition, it could help in some cases to fight emotional hunger or boredom.

        This would be possible in cases where a person eats out of inertia several times a day, even if he is not hungry, and through fasting he could train himself to differentiate hunger signals, so that he does not eat as food when you feel really hungry.

        On the other hand, the opposite effect could also occur and the person would lose control of their food and a binge eating occurs when the fast is broken. It is therefore important not to start this protocol, especially if it is a very prolonged and long-lasting fast, without the help, control and monitoring of a nutritionist and even a specialized team. composed of several professionals (eg, doctor, nutritionist and psychologist).

        However, it must be pointed out that a short 12 hour fast, where hardly any noticeable effort is made, is not the same as a 23 hour intermittent fast, so more risk could be taken and it is more likely to suffer from food anxiety, although we will discuss this in more detail later.

          2. Higher Concentration Levels

          Another possible benefit of the practice of intermittent fasting is that many people manage to increase their concentration while fasting and this could be evolutionarily justified since our most distant ancestors had to go hunting while fasting. and for this they had to have several refined cognitive functions to be able to achieve this.

          Additionally, some studies have indicated that when a person fasts, the levels of certain neurotransmitters, such as orexin and norepinephrine, which are associated with concentration, increase in their brain so that they can help us be more focused on who we are. Therefore, the practice of intermittent fasting might perhaps be more appropriate for people who, for work reasons, have to be very focused on their tasks and their work does not require high physical demands.

          at a time, the practice of intermittent fasting could be contraindicated for those who have a physically demanding job. In any case, it would be better to consult a specialist and, once the fast is put into practice, it would be important to do a self-analysis of the physical and mental state to know if this food protocol brings us well- the being and improving performance or, on the contrary, it harms us.

            3. Protection against depression

            In some research conducted with subjects suffering from depression, it was observed that a substance produced in the brain, known as BDNF (“brain-derived neurotrophic factor”), was almost absent in these depressed people at different levels. of those who were not. . Based on the results, one could conclude that the production of the neurotransmitter BDNF could protect us against depression.

            In other studies conducted on intermittent fasting, it was possible to observe that the practice of this food protocol helped a steadily increase BDNF productionso that its practice could help fight against depression, as well as it could also be beneficial for various cognitive functions.

            However, depression is a fairly complex process, in which several factors are involved, so in addition to intermittent fasting, several instructions must be followed such as maintaining healthy social relationships, practicing regular physical exercises, getting enough sleep and rest, following a healthy food, etc.

            4. It Could Lead to Improved Neuroplasticity

            When a person practices fasting intermittently, starting from certain hours, if it occurs in his organism a metabolic process known as “ketosis”, moment from which, after having had the energy of the carbohydrates, it will obtain it from the fats of the body. Some studies have indicated that when you enter ketosis, by alternating how you get energy between different processes, plasticity in the brain is also boosted.

            When we talk about brain plasticity or neuroplasticity, we refer to this ability of the brain to create new neural connections, which is an essential process when acquiring new learning, storing memories or new knowledge, between other processes.

              Possible negative effects of intermittent fasting

              After seeing the different positive effects that intermittent fasting could bring us, it is good to mention that we can also find some negative effects when practicing long-term fasting, so it would be important to be vigilant when fasting. We fast to detect possible antes for any indication that might indicate that fasting is harming us.

              Among the main psychological effects of intermittent fasting are some that, if they occur, are very negative. Next, we will see these possible negative effects, resulting from the long-term practice of this diet protocol.

              1. Eating Disorders

              Among the psychological effects of intermittent fasting, it should not be forgotten that the practice of intermittent fasting could trigger the development of an eating disorder or aggravate certain symptoms, and therefore, worsen the prognosis.

              This could be because intermittent fasting could be used as a tool when noticeably restricting the calories ingested from food throughout the day in anorexia or bulimia nervosa. Also, in cases of bulimia nervosa, fasting could increase anxiety levels that could precede a possible binge, so fasting could increase how often someone with bulimia nervosa binges.

              It could also increase the number of binge eating in people suffering from binge eating disorder, the practice of intermittent fasting would also be contraindicated in these cases.

              2. Anxiety

              Among the possible psychological effects of intermittent fasting, it should also be realized that the practice of this eating protocol could increase levels of cortisol, a hormone that is released in the brain in response to certain levels of stressso from certain levels it would lead to an increase in anxiety levels.

              It is also possible that the anxiety is caused by the desire to ingest food, which is more common during the first few days that intermittent fasting is practiced.

              In cases where a basic person has a predisposition to suffer from certain levels of anxiety, the most appropriate would be for him to see a mental health specialist before practicing intermittent fasting, as it may trigger symptoms of anxiety.


              First of all, it should be emphasized that fasting is not for everyone, as it could harm many people more than benefit them and, in case anyone decides to practice any type of intermittent fasting, he should first consult a professional specialized in this field. type of protocol and, at the start, the most suitable would be to start with the shortest intermittent fasting (12/12).

              Second, we need to be alert to any signs that might indicate that fasting is harming us, both physically (eg, dizziness, headaches, fatigue, etc.) and psychologically (eg, obsessing over food). , irritability, anxiety, etc.).

              Thirdly, it is important to emphasize that intermittent fasting is not a panacea and even less on its own, since to amplify its possible effects it must be accompanied by a healthy lifestyle, through a healthy diet, good rest, maintaining an activity and a healthy social and family life, as well as regular physical activity.

              Bibliographic references

              • Amigo, I. (2020). Handbook of Health Psychology. Madrid: Ediciones Pyramid.
              • Li, L., Wang, Z. & Zuo, Z. (2013). Chronic intermittent fasting improves cognitive functions and brain structures in mice. PLoS One, 8(6), e66069.
              • Mattson, MP, Moehl, K., Ghena, N., Schmaedick, M. & Cheng, A. (2018). Intermittent metabolic switching, neuroplasticity and brain health. Nature reviews Neuroscience, 19(2), p. 63-80.
              • Morandé, G., Graell, M. & Blanco, MA (2014). Eating disorders and obesity: a global approach. Madrid: Editorial Médica Panamericana.
              • Shojaie, M., Ghanbari, F. & Shojaiec, N. (2017). Intermittent fasting may improve cognitive function against distress by regulating the inflammatory response pathway. Journal of Advanced Research, 8(6), p. 697-701.
              • Singh, M. (July 14, 2022). The “shamanification” of the CEO of Tech. Cable.
              • Vazquez, M. (2018). Breakthrough Fitness: Ancient Lessons for Wild Health. Madrid: Editions Oberon.
              • Vazquez, M. (2021). Healthy Mind: Habits to optimize your brain and improve your health at any age. Barcelona: Grijalbo.

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