He intermittent fasting It is a feeding method that has become very fashionable in recent times. The reason? There are many professionals and followers who ensure the multiple health benefits, as well as the facilities it presents when it comes to losing weight and/or getting in shape. However, like almost everything in nutrition, there are as many supporters as detractors and, before starting this practice, it is advisable to put yourself in the hands of a professional who does a good follow-up, depending on the characteristics of each person.
“We define intermittent fasting (IF) such as the voluntary giving up of any food for specific and recurring periods, and meals are distributed in a different way than the traditional one”, they explain from the ENDOCS Endocrinology and Nutrition clinic. Not in vain, from the Spanish Society of Endocrinology and Nutrition (SEEN) point out that “this trend is not always accompanied by a correct prescription and, sometimes, the people who adopt it do not have all the necessary information. It is important to emphasize that fasting cannot be considered a dietsince this guideline implies restricting food for a certain time, while the concept of diet refers to the habitual intake of food and drinks”.
Types of fasting, from physiological to voluntary
“The shortest fast that many people do without realizing it is having dinner early and having 12 hours or so pass until breakfast. This is a fast that is going very well, because early dinner is recommended”, assures 20minutos the nutritionist Laura Jorge. This serious the so-called physiological fasting that occurs after staying without eating during the night and covers a period of time from 8 to 12 hours.
On the other hand, we would find voluntary fasting and the multiple ways that exist to practice it: daily, weekly and monthly.
- Fast for 16 hours: This is the most common pattern and consists of not eating anything for 16 hours, which usually include 8 hours of sleep, allowing intake for the following 8 hours. “The most common feeding ‘window’ is from 10 in the morning to 6 in the afternoon,” they say from the SEEN.
- I fast 2 days a week: The most common way to do this type of fasting is on alternate days, reducing the calorie intake consumed during them. Not surprisingly, a study published in 2017, led by Dr. Trepanowskide, showed that weight loss with this type of fasting was not significantly different from that of those who practiced daily caloric restriction.
- Alternate day fasting: This fasting method consists of restricting food about 3 or 4 days a week. For some people, it means completely avoiding solid foods on fasting days, while others prefer to consume up to 500 calories.
- 24 hour fast: This fast is practiced by those who choose not to eat food for 24 hours in a row. Many people fast from breakfast to breakfast or from lunch to lunch.
- Monthly fast: consisting of fasting a couple of days in a row each month, is practiced to a lesser extent.
- Skip meals: There are those who, instead of setting a certain time for fasting and eating, decide to restrict food randomly, skipping one or more meals of the day, be it breakfast, dinner or both.
Keys and tips to comply with the fast
Laura Jorge indicates that when it comes to intermittent fasting it is very important to take into account the type of food we consume. “Sometimes we focus on fasting, but we forget to make the rest of the meals healthy. If in the end you fast, but then you binge on junk food, it’s useless,” says the nutritionist. For this reason, there are a series of keys that must be followed to comply with the fast correctly.
First of all, avoid processed foods, with refined flours or added sugars and replace them with healthy proteins and carbohydrates that fill the stomach, while taking care of our health (fruits, vegetables and healthy fats). In this sense, it is also important to ingest food in two large meals and two other snacks (mid-morning and snack, for example). Hydration is essential, since water helps to quench the thirst that hunger produces and, if it is also flavored, it is a good way to ‘cheat’ the stomach. Finally, it must be taken into account that the tea or coffee are great allies for intermittent fasting, as caffeine is a stimulant that can increase your resting metabolic rate and is effective in reducing appetite.
Intermittent fasting: for or against?
Intermittent fasting has its detractors and its defenders. the nutritionist Carlos Riosin his book eat real foodensures that “our body is well adapted to fasting, since we have spent much of evolution foraging for food on an empty stomach. (…) This intermittent fasting may be involved in repairing DNA and body cells, increasing longevity, according to recent research. However, you don’t have to be fasting to stay healthy,” he says.
For his part, the researcher Idoia Labayen Goñi, professor of Physiology at the University of Navarra and director of the ISFOOD Research Institute, commented at a congress of the Spanish Society of Endocrinology and Nutrition (SEEN) that “scientific evidence regarding its effectiveness as a method of controlling body weight is very scarce. To date, the studies have been carried out in very small samples and with interventions of short duration”.
The opinion of laura george, our consulted nutritionist, follows the same line: “I believe that with the issue of fasting you have to be very careful, yes there is some evidence that describes certain benefits, but in my opinion in nutrition everything depends on the person. There are those who use fasting as a weight loss diet because it has become very fashionable, there are people with eating disorders who are fasting, so The issue of fasting, like everything in nutrition, will depend on the person, with what intention it is being used… As always, you have to start by getting to know the person, establishing a base of healthy eating and a healthy relationship with food and with ourselves, and from there, we could consider whether it is beneficial for that person. person to fast or not”.
References
Cancer Minchot, E. & Moreno Borreguero, A. Spanish Society of Endocrinology and Nutrition (SEEN). (2020, November). Intermittent fasting as a trend. Viewed at https://www.seen.es/ModulGEX/workspace/publico/modulos/web/docs/apartados/1774/261120_051921_3568335762.pdf on February 13, 2023.
Spanish Society of Endocrinology and Nutrition (SEEN). (2022, October 26). Intermittent fasting is not advisable for all people with obesity, according to the SEEN. Viewed at https://www.seen.es/portal/documentos/np-ayuno-intermitente-63-congreso on February 13, 2023.
Trepanowski JF, Kroeger CM, Barnosky A, et al. Effect of alternate-day fasting on weight loss, weight maintenance, and cardioprotection among metabolically healthy obese adults: a randomized clinical trial. JAMA Intern Med. 2017;177(7):930–938. doi:10.1001/jamainternmed.2017.0936