What are the health benefits?
By relieving the body of the toxins that burden it, intermittent fasting corrects states of fatigue: sleep improves from day 1 and tone returns after day 3. The complexion is also clearer and the skin is healthier. “It allows a weight loss of around 1 kg per week, as part of a fast followed over a full week,” says the nutritionist.

Fasting is also thought to reduce pain, stiffness and the consumption of NSAIDs in people with rheumatoid arthritis1. This food method would also improve concentration, according to a study published in the magazine International Journal of Obesity2 by promoting the renewal of neurons in the brain.

Is it dangerous for health?
Carried out for too long and without medical supervision, fasting could be the cause of deleterious effects on the body. First, dizziness and headaches. If it continues, it can lead to muscle wasting and macronutrient deficiencies including protein, as well as minerals, such as iron, and cause anemia.

It can also be harmful to the heart: certain heart problems, in particular arrhythmias, are a contraindication to overly restrictive diets. This risk exists especially when the restriction lasts too long because it weakens the heart muscle according to the Haute Autorité de Santé3. Check with your doctor and cardiologist before you start.

What effects in cancer?
Opinions are still divided on the anti-cancer effects. Numerous studies, carried out on animals, had already shown that deprivation of food before chemotherapy could help preserve healthy cells while making cancer cells more vulnerable to treatment. In 2017, INCa looked into the question and issued an opinion that “the overall analysis of available scientific knowledge, in particular clinical knowledge, does not allow us to conclude that these regimens are beneficial in preventing cancer or during treatment. In cancer patients, the loss of weight and muscle mass observed in clinical studies suggests a risk of worsening malnutrition and sarcopenia, two poor prognostic factors recognized during treatment “4 .

But a study published in June 2020 in the famous journal Nature reopens the debate5: carried out on 129 patients with breast cancer, it shows that those who had been deprived of food for three days before and three days after their session of breast cancer chemotherapy had responded better to this treatment than those who had continued to eat normally.

“Fasting can be an ally in the fight against cancer, recognizes Raphaël Gruman. However, because this disease and its treatments can also lead to undernutrition causing a deterioration of the general condition, if the patient wishes follow it, it must be supervised by a health professional “.

Advantages of intermittent fasting
If it is followed over a long period of time, because the food intake is spread over two or even three meals, this eating method is not unbalanced and does not lead to deficiencies or fatigue;
It is a health ally: it improves the digestive system, sleep, the quality of the skin, brings renewed tone, relieves pain in cases of rheumatoid arthritis and ensures proper functioning of the brain;
It helps to lose weight, in the order of 1Kg per week;
It is compatible with special diets such as vegetarian, vegan, gluten-free, lactose-free, salt-free, kosher and halal;
It can be short lived.

Disadvantages of intermittent fasting
If the fast lasts for too long and is not supervised, it can lead to significant deficiencies, muscle wasting as well as regaining the lost weight. The Haute Autorité de Santé recommends losing no more than 1 to 2 kilos per month3;
It can be responsible for eating disorders, compulsions for sweet;
This eating style can be de-socializing: skipping dinner, for example, limits going out with those around you.