PARIS, May 31 — As summer approaches, a number of diets are gaining popularity on social networks. The latest is water fasting. This diet consists of drinking only water or liquids for one or more days. But this is not without health risks.

After intermittent fasting, which involves alternating periods of eating and fasting at given times, water fasting has become the latest craze on TikTok for its supposed health benefits. This fast involves consuming only water and other liquids (coffee, tea, infusions, vegetable broth) for a day or more. According to its followers, this fast can help you lose weight and revitalise your digestive system.

There are many ways to practice water fasting, but experts agree that the ideal duration is five days, once a year. For those new to water fasting, an initial period of 24 to 48 hours is recommended. But is it really an effective solution for weight loss?

According to a study from the University of Illinois Chicago (USA), published in the journal Nutrition Reviews in 2023, water fasting may not be effective for long-term weight loss.


This review of eight studies on water fasting reported that participants experienced significant short-term weight loss.

Those who fasted for 5 days lost 4-6 per cent of their initial weight, those fasting for 7-10 days lost 2-10 per cent, and those fasting for 15-20 days lost 7-10 per cent of their original weight.

In one of the studies reviewed, which tracked participants’ weight after the fast ended, people were found to have gained back all they had lost in a five-day water fast within three months.


“My overall conclusion is that I guess you could try it, but it just seems like a lot of work, and all those metabolic benefits disappear,” says Krista Varady, professor of kinesiology and nutrition, who led the research, quoted in a news release.

Water fasting can have side effects, including mood swings, migraines and vomiting. It can exhaust you physically and mentally, preventing you from engaging in strenuous physical activity.

Krista Varady also noted that “participants in these prolonged 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 during weight loss, where more fat is lost than muscle,” according to the study news release.

Water fasting is not recommended for certain categories of people, including children and adolescents, people with medical conditions such as diabetes, pregnant and breastfeeding women, and adults over 75.

“When done long term, water fasting can be dangerous and even fatal without medical supervision because of nutrient and electrolyte imbalances,” Kaytee Hadley, a US-based functional medicine dietitian, told Forbes,

It’s crucial to consult a doctor before attempting prolonged fasting, as going 24 hours or more without food can be dangerous.

Finally, it’s worth remembering that water fasting is not a miracle solution for weight loss or detoxification. Its effects vary from one individual to another, and it should be practiced with caution. — ETX Studio