The general idea of this proposal is to stop eating for controlled periods of time: from not eating anything for a few hours a day to fasting two days a week, which ends up leading to feelings of guilt, binge eating and anxiety.
If you’re an adult, chances are you’ve tried a few diets throughout your life. Either to lose a few extra pounds, or to get more muscle, or to feel healthier. But the reality is that most of them will have forced you to put aside your favorite food in favor of others much less harmful and more boring. And while the results are sure to have been visible in almost all of them, the constant feeling of hunger and the need to satiate cravings will make you rethink it twice before giving “fitness” a chance again. For this reason, alternatives such as “fasting”, the latest shout in the so-called miracle diets, are as dangerous. Intermittent fasting was something to which the first inhabitants of the planet were exposed and, as such, it was to be supposed that the organism would be adapted to these periods of lack. But that is not the case: except for preliminary studies in mice, there is no scientific evidence of its benefits in humans.
In front of the mantra that invites five meals a day and the one that ensures the benefits of not skipping breakfast, this palodiet proposes restricting caloric intake using a period of fasting that can follow different patterns: 16:8 (abstain for 16 hours a day and eat within a period of eight), 5:2 (perform the usual routine for five days a week and fast the other two) or 12:12 (you can only have breakfast and dinner half a day apart). Although Michael Mosley’s documentary “Eat, fast and live longer” and Kate Harrison’s book “The 5:2 Diet” have highlighted all the graces of this practice, the reality is that the overall nutrient intake it advocates is very deficient. “Throughout history, similar situations have arisen in the form of a religious precept. This is the case of Lent for Catholics, Ramadan for Muslims or Yonki Pur for Jews. But its very rules state that, in the event of illness, some patients are exempt from doing so because it is obviously dangerous. This already gives an idea that indiscriminate fasting is not good,” says Albert Goday, president of the Spanish Society for the Study of Obesity Foundation and head of Endocrinology at the Hospital del Mar in Barcelona.
The human body has the capacity to tolerate fasting, but up to a certain limit. It is true that this is a machine designed to consume energy constantly, but also stores it discontinuously. “Therefore, in situations of interruption of this contribution, we implement various mechanisms of adaptation: some of them are focused on the production of ketone bodies as a result of the combustion of our fat reserves, to which some recent research has conferred benefits. But only for short periods of time. If this practice is prolonged, more harmful processes are set in motion for the organism”, Goday adds. And this possibility is not always taken into account.
The dangers involved therefore depend on the length of the fast and the overall characteristics of the fast. For Irene Bretón, a doctor in the Endocrinology and Nutrition Service at the Gregorio Marañón Hospital in Madrid, prolonged practice can lead to nutrient deficiencies (such as potassium, magnesium or thiamine), as well as loss of muscle mass if the minimum protein requirements are not met. “If total calorie intake is less than energy needs, this will lead to weight loss. However, an adequate guideline to treat overweight or obesity should be based on education in nutrition, choosing a variety of products such as vegetables, fruits, legumes, nuts, dairy products or lean meats,” says Breton. But in addition to choosing the right products, it is essential that their distribution throughout the day is adequate. In this way, overfeeding and disordered intake, especially at night, contribute to weight gain and other metabolic problems. “We must not lose sight of the fact that the physiological response to fasting leads to a reduction in energy expenditure.
Attractions and anxiety
Weight loss is the main goal of people on these diets. In fact, some studies suggest that, compared to other classic options of continuous caloric restriction, it is equally effective. However, there is currently no long-term research to provide sufficient information about this effective weight reduction or the consequences of this regimen. In addition, it is considered especially dangerous for pregnant women, lactating mothers, diabetics or patients with hepatopathies and those under 18 years of age. “When young people eat a diet without supervision, they can develop important physical consequences: nutritional deficiencies, stagnation of growth, irregularities in menstruation… It must be borne in mind that adolescence is a key period of development and that the vast majority of these diets are initiated by low self-esteem and social pressure,” says Ricardo Camarneiro, psychiatrist of the Eating Disorders Unit of the Niño Jesús Hospital in Madrid. “This type of practice has consequences on mental health, and can cause stress, anxiety and insomnia problems”. As well as a constant concern for food that could lead to cases of bulimia and anorexia.
“Fasting periods can lead to episodes of binge eating that lead to feelings of guilt or purgative maneuvers, so they are not advisable for patients who have or may develop these disorders,” says Francisco Botella, spokesperson for the Spanish Society of Endocrinology and Nutrition. Well, if intermittent fasting is based on a controlled movement of food over a longer or shorter period of time, the metabolic disorder that generates can be a clear trigger. In fact, many eating disorders begin with malpractice and a lack of information. This is the case for people with body dissatisfaction, image distortion and intense fear of gaining weight, so they choose to restrict certain products and control quantities. These are the common characteristics of anorexia nervosa. “Intermittent fasting, therefore, could trigger an obsession with ingestion times and a stiffer diet”, warns Ángela Quintas, specialist in Organic Chemistry and nutritional coach.
Unlike this type of patient, people suffering from bulimia nervosa are characterized by this lack of control, that is, by their impulsivity towards consumption and the use of inappropriate compensatory techniques to avoid weight gain. “Therefore, this habit could be used as one of these compensations which, together with an increased characteristic anxiety, could trigger another of the key symptoms: overcrowding”. The same ones that this regime wants to avoid at all costs.
Don’t forget that the body’s priority is to survive. So when the mechanisms of stress are activated, all the others are secondary. In this context, levels of pregnenolone (precursor of sex hormones) decrease in favor of cortisol. And, from then on, it is only a matter of time before fertility problems, impotence, muscle loss, chronic fatigue develop… A whole cocktail of symptoms that will make your fasting an experience that you will never want to repeat, even though you have lost a couple of kilos. If anything.