Fast
In nature, because food is not always available, intermittent fasting is part of the survival routine and any animal organism can handle it.
Absolute fasting is defined as the failure to eat any solid or liquid food for a certain period, usually between 24 hours and a few days.
Imposed Fast
For evolutionary reasons, the human body (thanks to its hormonal flows) is able to adapt optimally to the absence of food. The same cannot be said for an excessive diet, as a result of which it can become ill with the so-called diseases of well-being. (obesity, dyslipidemia, type 2 diabetes mellitus, hypertension, etc.).
In this regard, some specialists propose to treat overweight and metabolic diseases through the so-called therapeutic fasting. This practice takes place under conditions of medical supervision and nutritional support (with food supplements and water).
Beneficial or Harmful?
Fasting can be beneficial or harmful based on some factors; for example: duration, completeness of food abstention or nutritional support, medical control, pathological conditions for its application, etc. Not all forms of fasting are the same, some are extremely debilitating and unmotivated, others less exhausting and more rational.
Fasting, whether controlled or uncontrolled, therapeutic or not, is still very stressful for the body and mind. However, its potential harmfulness mainly depends on the parameters with which it is programmed.
An example of ethically "highly questionable" fasting is the so-called tube diet. This is based on a form of chronic fasting, during which the organism is supported exclusively by enteral artificial nutrition (nasogastric tube). Similar practices can induce:
- Physical debility and tendency to malnutrition and ketosis (see below)
- Limitation of motor activities
- Food miseducation.
On the contrary, in subjects suffering from metabolic pathologies, short periods of food stop - such as, for example, the emphasis on the night fasting period (the one during sleep, taking it from 8 to 12 or 14 hours) - does not cause side effects. and favor the remission of certain metabolic parameters (especially hyperglycemia and hypetriglyceridemia) or other disorders (fatty liver, gastroesophageal reflux, etc.). Obviously, the example just reported does not represent a real fast and this constitutes the only form of food abstention potentially beneficial and free of side effects.
Many believe that absolute fasting can negatively affect hormonal flows, specifically by suppressing the action of the thyroid gland (the one that secretes the hormones responsible for regulating metabolism); this is only partially true. In fact, prolonged fasting reduces without doubt the secretion of thyroid hormones, however, in general, this reduction does not occur before 24 or 48 hours.
There is some scientific evidence that fasting can play an important role in people receiving chemotherapy, but further studies are needed to define its actual effectiveness and possible clinical application.
Can It Be Therapeutic?
Some centers specialized in the treatment of metabolic diseases use therapeutic fasting for weight reduction and for the restoration of metabolic parameters.
Rarely, therapeutic fasting systems are based on the irrevocable abstinence of food and none of these prohibit the use of water. On the contrary, the tendency is to encourage the intake of liquids and, sometimes, certain plant foods to certain portions (especially in the case of certain particular diseases).
According to the experience of the operators who propose therapeutic fasting, the greatest difficulty consists in the initial acceptance of the therapy, not in the protocol itself. Few believe they can survive 2 or 3 weeks without eating but, on the other hand, many have spontaneously reached 30-40 days.
How does it work?
The first 24-48 hours of therapy include complete fasting with the sole intake of water.
In this phase (the hardest), the body consumes most of the sugar and triglycerides present in the blood; obviously, glucose levels are kept progressively stable by hepatic glycogen, while motor action (typified by absolute rest) is mainly supported by muscle glycogen stores.
ATTENTION! As of now, it is already quite clear that this technique cannot be used in the case of liver impairment, type 1 diabetes mellitus or other diseases that involve significant metabolic difficulty.
The "true" metabolic action (or rather, that sought by therapists) occurs at the end of this first phase, that is when the glycogen reserves are reduced "to the" bone. At this point, the body begins to burn mainly the adipose tissue, with the production and blood flow of molecules called ketones.
Sometimes, in compromised subjects or those who take certain drugs, therapeutic fasting involves the intake of vegetable juices such as squeezed and centrifuged to reduce the state of ketoacidosis.
Therapeutic fasting is interrupted in progressive matters, starting with the intake of juices and centrifuged, then with smoothies and vegetable pieces, reaching up to the intake of cereals and legumes.
