As summer approaches, many diets are on the rise on social networks. The latest one? Water fasting. This diet involves drinking only water or liquids for one or more days. But this practice is not without health hazards.
We have already heard of intermittent fasting, which involves alternating periods of eating and fasting over certain periods of the day. But recently, it is water fasting, or “water fasting” in English, which is all the rage on TikTok because of its supposed health benefits. This fast consists of swallowing only water and liquids (coffee, tea, infusion, vegetable broth) for a day or more. According to its followers, this cure would help lose weight and revive the digestive system.
There are several ways to practice water fasting, but experts agree that the ideal duration is five days, once a year. For those who are new to the subject, an initial treatment of 24 to 48 hours is recommended. But is it really effective for weight loss?
No long-term benefits
According to a study from the University of Illinois at Chicago (United States), published in the journal Nutrition Reviews in 2023, water fasting would not be effective for losing weight in the long term. Study participants experienced noticeable weight loss in the short term. People who fasted for five days lost between 4 to 6% of their initial weight, those fasting for seven to ten days lost 2 to 10%, and those fasting for fifteen to twenty days lost 7 to 10% of their body weight. original weight.
However, all study participants immediately returned to their initial weight after stopping the fast. “My overall conclusion is that one can try, but it takes a lot of work and all the metabolic benefits disappear“, explains Krista Varady, professor of kinesiology and nutrition who led the research, in a press release.
Significant side effects
Water fasting can also cause side effects, including mood changes, migraines or vomiting. It can also leave you physically and mentally exhausted, preventing you from engaging in strenuous physical activities. Krista Varady also noted that “Participants in these extended fasts lost about two-thirds of their weight in lean mass and one-third in fat mass. This is the opposite of what happens most of the time when losing weight, where you lose more fat than muscle.”.
Real contraindications
It is also not recommended for certain categories of people, including children and adolescents, people suffering from pathologies such as diabetes, pregnant and breastfeeding women and adults over 75 years old. “When practiced long-term, water fasting can be dangerous or even fatal without medical supervision due to imbalances between nutrients and electrolytes.“, explains Kaytee Hadley, functional medicine dietitian based in Virginia (United States), consulted by Forbes,
It is crucial to consult a doctor before attempting a prolonged fast, as going 24 hours or more without food can be dangerous. Finally, it is worth remembering that water fasting is not a miracle solution for weight loss or detoxification. Its effects vary between individuals, and it should be practiced with caution.
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