Fasting is a word mentioned a lot lately. We hear it from friends and family. It is practiced by the teacher, the gym buddy, the janitor at work and the office colleague. And, above all, we hear that it is gaining followers among famous people from film and television. According to what they say, it makes them feel healthier. But what exactly are we talking about? Is it really healthy?
In general terms, fasting consists of completely or partially abstaining from eating or drinking for a certain period of time, although non-caloric beverages may be included during the time in which it is carried out.
That being said, there are many ways to fast. It is possible to do this for long periods; for example, for three days. Or we can practice so-called intermittent fasting, in periods of 24 hours (every other day).
A simpler way to fast is what we call time-restricted eating. In this case, we eat every day, but we reduce the number of hours we dedicate to it. For example, we can eat all our daily meals in a period of 10 hours and fast for the remaining 14. Or, if we are more strict, we will eat for 8 hours and refrain from eating anything for the remaining 16.
The fasting period leaves the cells without their main source of energy: nutrients, especially sugars. Our cells have to adapt to this situation and, consequently, the body modifies its metabolism to look for other means of obtaining the necessary energy.
It happens like this: while the cells reduce their activity (slow down), the liver adapts the metabolism and manufactures chemical compounds called ketone bodies as an alternative source of energy. Finally, fatty tissue releases stored fat reserves.
Fasting protocols affect our entire body. First, the brain improves its ability to respond to stress and its inflammation is reduced. In addition, the heart becomes more resilient, blood pressure drops, control of blood glucose levels increases, intestinal inflammation is reduced and the state of our intestinal microbiota improves.
Fasting can help improve the quality of aging, as we are studying in our research group, but it also seems to generate a greater feeling of hunger.
Regarding weight control, this practice can indeed help you lose weight and, more importantly, reduce fat mass. However, it is also possible to lose muscle mass when fasting. So one of lime and another of sand.
Losing weight is not easy: following a diet that involves reducing the calories we eat is, like fasting, difficult to maintain. So what is the best option? There is no single answer. Each person is different, as my grandmother would say: for some of us it may be easier to eat every day, reducing the amount, and for others it will be less difficult to fast.
There is also no scientific evidence that fasting provides greater benefits than conventional diets. This is probably because the result depends on each individual. This is what we call precision nutrition, which is not the subject of this article.
In any case, there is some evidence. Some studies have suggested that adherence or compliance with fasting protocols is greater than that of conventional calorie-restricted diets.
As for the existing modalities, time-restricted intake is easy to apply in our daily lives and provides benefits, as long as it is early. By this I mean that, as has been proven, doing the fasting period in the afternoon (early dinner) provides more advantages. In fact, the results indicate that abstaining from eating in the morning (delaying breakfast) does not imply any benefit.
It is best to put yourself in the hands of a nutrition specialist who can help you design guidelines adapted to your needs and possibilities.
But be careful! During the fasting period it is possible to suffer episodes of hypoglycemia. That is why it is necessary to monitor your health during the time it is carried out, especially if you suffer from diabetes.
If you have any other health problems, it is important to consult with a doctor before starting fasting. And, finally, if you practice sports regularly, the protocol must be coordinated with said practice.
