The benefits of intermittent fasting, and how to do it

Do you know what intermittent fasting consists of? Do you know its benefits and possible risks? A scientific review has recently come to light that reveals very interesting results derived from intermittent fasting.

In this article we will see, in detail, what this habit consists of on a practical and nutritional level, its possible benefits, their scientific bases, and how to carry it out to avoid entering a risk situation for the health.

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What is this health practice?

There are various formulas for intermittent or sporadic fasting, such as the daily periodicity (the best known), which consists of less than 12 hours of fasting, the best known being the “16/8” pattern: 16 hours of fasting and 8 hours of feeding. There is also the weekly: generally one or two days a week of fasting, followed or not, and finally the monthly: fasting two days in a row each month.

At the time level, the most frequent practice is to eat from 10 in the morning to 6 in the afternoon (taking into account intermittent fasting on a daily basis). In the fasting period, 8 hours of sleep are contemplated.

Food and calories in intermittent fasting

In relation to caloric intake, it is considered that with the fasting period the usual general intake of kilocalories to between 300-500 per day (approximately, and depending on the age, sex and physiological conditions of the person).

Regarding the products to be consumed, these must always be fresh, nutritionally balanced, healthy food especially vegetables and fruits. Preferably home-cooked and seasonal foods.

The basis of food when not fasting are vegetables and fruits, but always taking into account legumes, seeds, nuts, foods whole grains (with labels that support it), as well as foods of animal origin (for those who are not vegans) such as eggs, dairy, fish, seafood and meat.

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Benefits of intermittent fasting

Numerous scientifically rigorous studies have led to the conclusion that, in summary, eating in a 6-hour period and fasting for 18 hours can trigger a metabolic pattern change specific; this is, go from a metabolism of obtaining energy from glucose (in the liver), to a metabolism from ketones and fatty acids (in adipose tissue; i.e. fat).

Said change in metabolism would entail a series of changes at the cellular level, which would imply increased resistance to stress, increased longevity, as well as a decrease in the incidence of certain diseases, such as cardiovascular diseases, obesity, diabetes and cancer among others.

This series of articles demonstrate the benefits of intermittent fasting, showing that these are not only weight loss and the reduction of free radicals (which oxidize and damage our cells), but they go more there.

Among the benefits of intermittent fasting, we find fat loss while maintaining muscle mass, the improvement of spatial, verbal and associative memory, as well as the improvement of global cognition (mental processes).

Physiological processes involved

On the other hand, intermittent fasting triggers adaptive cellular responses that are integrated across organs. Thus, glucose regulation is improved, stress resistance is increased and inflammation of cells is also suppressed.

During the fast, cells activate pathways that enhance intrinsic defenses against oxidative and metabolic stress and those that eliminate or repair damaged molecules.

Upon recovery from fasting (eating and sleeping), cells increase protein synthesis, undergoing growth and repair. Maintaining an intermittent fasting regimen, particularly when combined with regular exercise, results in many long-term adaptations that improve overall mental and physical health.

Risks to be aware of

Although we have learned about some of the benefits of intermittent fasting, we must be cautious. Specialists from the SEEN (Spanish Society of Endocrinology and Nutrition), show that, despite the possible benefits of intermittent fasting, this cannot be considered a diet.

This is because this practice refers to the restriction of food for a certain period of time, while the concept of diet refers to a common practice regarding the intake and restrictions of food and drinks.

In addition, experts emphasize that in some vulnerable people it could develop an eating disorder by this habit, if it is not carried out in a controlled and studied way.

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Importance of healthy lifestyle habits

In order to have a healthy life and maintain a normal weight (ideal weight according to our height and physical characteristics), even taking into account the benefits of intermittent fasting, it is essential not to forget to carry out and have healthy eating habits, based in an education around food and nutrition.

Some basic advice for a healthy lifestyle at a nutritional level would be: always plan menus, eat five meals a day, do not snack between meals, control the amounts of food, eat balanced and from all food groups, eat slowly and limit sweets and processed products in general. Obviously without forgetting the recommended amounts, and not forgetting physical exercise.

Intermittent fasting under medical supervision

As we have seen, scientific studies have shown the benefits of intermittent fasting in relation to many health conditions, such as obesity, diabetes mellitus, cardiovascular diseases, cancers, and disorders neurological.

At the level of animal experimentation (rodents and primates), intermittent fasting has been shown to improve health throughout life, while at the clinical level (people), studies have only been conducted for short-term periods (months), so that there is still a lot of research to do.

Thus, the benefits of intermittent fasting have a scientific basis. Anyway, It is a delicate practice that must always be carried out under medical supervision..

Always keep in mind that intermittent fasting should be done in the short term, and it is not recommended for everyone, since each person has their physiological needs, and of course, it should not be done in excess.

Bibliographic references:

• Mahan L, Kathlee, Janice L, Raymond (2017). Krause. Diet therapy. Elsevier Publisher. 14th edition.
• Mark P. Mattson, Valter D. Longo, and Michelle Harvie (2016). Impact of intermittent fasting on health and disease processes. Aging Research Reviews (Aging Res Rev).
• Rafael de Cabo, Ph.D., and Mark P. Mattson, Ph.D. 2019. Effects of Intermittent Fasting on Health, Aging, and Disease. The New Journal of Medicine (NEJM).
• Stephen Anton, Stephen, Leeuwenburgh, Christiaan (2013). Fasting or caloric restriction for Healthy Aging. Experimental Gerontology (Exp Gerontol).