Since approximately the 1980s, our society has faced worrying overweight and obesity figures. Excess kilos and body fat have been defined as a multifactorial chronic disease that reduces life expectancy and quality. It is a factor that increases the risk of mortality and suffering from disability, chronic diseases such as hypertension, cardiovascular ailments, type 2 diabetes and different types of cancer, among others.
One of the effects promoted by excess body fat is the pro-inflammatory state and the dysfunction of the immune system that it generates in the body, which would explain the increased risk of mortality and suffering from chronic diseases. Fatty or adipose tissue is made up of cells called adipocytes that, when they accumulate too much fat, begin to secrete inflammatory molecules, and some of them activate our body's immune response.
For example, some “warriors” of our defenses are put into action, such as macrophages, which increase inflammation in the fatty tissue itself and increase the dysfunction of adipocytes, setting in motion the vicious circle of a toxic relationship for our body. Thus, obesity becomes a low-grade chronic inflammatory disease.
In the last decade, a dietary pattern that was originally born to combat excess weight and body fat has become popular: fasting by restricting the intake window. This type of intermittent fasting is based on limiting the time in which we eat daily (between 4 and 10 hours). During the rest of the day (from 2 to 8 p.m.) we would only drink calorie-free drinks such as water, infusions and/or coffee, to stay hydrated.
In a simple way, without the need to count calories or modify or restrict foods in the diet, fasting by restricting the intake window offers cardiometabolic benefits even if there are no notable changes on the scale. All these qualities explain the high levels of compliance and satisfaction among the people who carry it out.
One of the keys to this type of fasting lies in aligning our circadian rhythms, that is, the “internal clock” that governs the functioning of our organs, related to solar time. It has been proven that this biological mechanism controls the innate and adaptive responses of the immune system.
For example, eating “out of phase” with circadian rhythms (eating at night or having an eating window of twelve or more hours) promotes chronic low-grade inflammation. Therefore, restriction could be exerting its anti-inflammatory effects through modulation of the immune system.
In addition, we must take into account that this type of fasting increases the diversity of our intestinal microbiota and different groups of beneficial bacteria, which would also have a positive impact on inflammation and the immune response itself.
To check if there is a relationship between the benefits of this dietary habit and the improvement of the immune system, we have carried out a study in which we analyzed the 25 works carried out, with a total of 936 participants, in this area of research.
Thus we were able to determine that, indeed, those who follow the restriction of the intake window register a decrease in tumor necrosis factor alpha (a biomarker of inflammation) and leptin. This hormone secreted by fatty tissue is not only responsible for regulating appetite, but also modulates the inflammatory and immune response.
The findings would be related in part to the weight loss associated with fasting, although other previously mentioned factors such as the positive impact on metabolic health, the immune system or the improvement of the intestinal microbiota have weight.
Although further research is needed to establish more solid conclusions, these results are promising and open a way to consider that limiting the hours in which we eat could be of great help to treat different diseases that cause chronic low-grade inflammation, such as obesity, type 2 diabetes or depression.
This article was originally published on The Conversation website. You can access it through this link.
