Intermittent fasting, what if I don’t eat?

The intermittent fasting It is the fact of avoiding food intake for certain hours in a meditated and controlled way. We do not talk about starvation or hunger strikes. As is logical, all the scientific information that we have has tested different fasting patterns in specific population groups and under medical supervision.

What do we know about fasting?

When we seek information about fast We can read the most diverse information, from pages where they warn us of the supposed "fatal" consequences of fasting to websites where they expose us all the, also supposed, possible benefits. Fasting is often linked to religious, spiritual and physical issues to detoxification of the body. As is often the case in most issues in which we find such opposing currents, reality is usually neither on one side nor on the other. Let's see what we know today about fasting.

What is and how to do intermittent fasting?

There are different possible fasting guidelines or patterns, but fundamentally we can talk about deprivation of daily, weekly or monthly intake, and of semi-fasting (or FMD):

• Daily: It is the fast that involves avoiding the intake for a series of hours a day, and is followed daily. We are talking about a deprivation of intake of from 12 hours, for example. Although it may seem like a lot, these hours usually coincide with the rest period That should take about eight hours by now. This period can be extended by performing the 16/8 pattern, that is, 16 hours during which we do not eat food and eight hours during which we do. And it even reaches the 20/4 patterns.
• Weekly: it is fasting that consists of avoiding the intake for a whole day, and once a week is the most common, although there are patterns that propose two days of fasting per week, separated by a minimum of two days between them.
• Monthly: these guidelines are the least common, they usually propose a longer fasting time, 48-72 hours, once a month. But different authors defend that the longer one fasts is not better and they do not recommend more than 24 hours.
• Semi fasting or FMD: these are the abbreviations of Fasting Mimicking Diet or, what is the same, an imitation of fasting that, instead of consisting of the deprivation of food for a few hours, limits the intake to few amounts, but maintained for four or five days.

Possible risks

• Alteration of blood glucose levels: It is true that blood glucose fluctuates when we eat, but we must also take into account that the body has mechanisms to regulate these levels and keep them within the appropriate margins, releasing insulin when it has glucose with meals, and releasing glucagon when it does not arrive. . If the blood glucose levels are altered is due to different metabolic pathologies such as diabetes.
• Performance decline: physical performance depends on many factors, among them, of course, the type of physical activity that is carried out and from what we know there are adaptations to fasting exercise. The most studied cases are in athletes who perform Ramadan and there are both studies that assess a possible small decrease in performance and others that find no difference. We must also bear in mind that during Ramadan there is also water restriction and the decrease in performance could be associated with dehydration.
• Loss of muscle mass: indeed, prolonged fasting is considered to jeopardize the maintenance of muscular state. Therefore, fasting for more than 24 hours or severe restrictions for several days can be negative in this regard. However, this does not happen when we are talking about fasting less than 24 hours, there are even studies in which greater muscle conservation has been seen practicing intermittent fasting than caloric restriction based on reducing dietary fat.
• gastrointestinal disorders: there is information stating that fasting interferes with the levels of gastric acid secretion secreted by the stomachSo, as we have seen in other sections, there is an adaptation to the changes in the hours of food intake. Again we find studies in which people who have followed Ramadan are assessed and how acid levels are regulated without this being a problem.
• Headaches, irritability, and difficulty concentrating: It is possible that discomfort occurs in a person accustomed to making more intakes begins to fasts, but in cases of controlled and adequate fasting these possible problems are mild and disappear with adaptation. As always, you have to adapt the pattern to the person.
• Compensatory meals: this possible problem is very personal and subjective, while in some cases staying a few hours of fasting can favor that the first post-fasting intake is more impulsive and copious, for other people it may be worse to be doing lots of small intakes where you never get satiated.

Possible benefits of intermittent fasting

• cardiovascular and metabolic benefits: There are different studies in which an improvement in different biochemical parameters related to cardiovascular health and blood pressure has been observed, such as a reduction in triglycerides and an improvement in the lipid profile, as well as an increase in insulin sensitivity.
• Benefits at the inflammatory level: it has been possible to study at an experimental level how prolonged intermittent fasting has positive effects on the inflammatory state of the body decreasing biochemical parameters such as C-reactive protein.
• weight loss while preserving muscle mass: As we pointed out before, weight loss programs have been carried out using intermittent fasting patterns and better results have been obtained in terms of maintaining muscle mass than with low-calorie diets, obtaining the same weight loss.
• Other possible benefits: There is also research that has found different positive effects attributable to the proper use of intermittent fasting patterns such as improvements in anti-aging systems, neural plasticity, etc..

WHAT YOU SHOULD KNOW

• Intermittent fasting is the regulation of intake in a controlled way, maintaining certain hours without taking food.
• If you want to follow intermittent fasting guidelines, it is necessary consult a healthcare professional to adapt them to each specific case.
• There are studies that have obtained positive results in specific groups and in a controlled way, but more research is needed on this.
• Before doing any type of diet or fasting, it is best to consult a specialist. Insurance has a large medical staff of nutritionists.

Mercè Gonzalo Bachelor of Food Science and Technology Diploma in Human Nutrition and Dietetics