Water fasting could help you lose several pounds in a few days, but you may gain them back quickly.
- A water fast, which lasts 5 to 20 days, has resulted in mild to moderate weight loss of 2 to 10 percent.
- In some people, weight regain has been observed within three months. For others, only a small portion of the lost weight was regained after the fast ended.
- The most common side effects were headaches, insomnia and hunger.
Water fasting consists of stopping ingesting solid foods and consuming only water or herbal teas for several consecutive days. This method, during which you must be followed by a professional, is often carried out with the aim of detoxifying the body. Many followers claim that it eliminates accumulated toxins and cleanses the digestive system. However, some people resort to it to lose pounds. But, according to researchers at the University of Illinois at Chicago, it is not certain that this weight loss is sustainable.
Intermittent fasting leads to noticeable short-term weight loss
In one study, scientists reviewed eight research studies on water fasting to determine the cumulative impact of water fasting on weight loss, as well as a number of other metabolic factors. According to their results, published in the journal Nutrition Reviewsthis method resulted in mild to moderate weight loss of 2-10%.
In detail, people who fasted for five days lost 4 to 6% of their weight, those who fasted for seven to ten days lost 2 to 10% and those who fasted for 15 to 20 days lost lost 7 to 10%. “About two-thirds of the weight lost is lean mass and one-third fat mass. The excessive loss of lean mass suggests that prolonged fasting may increase muscle protein breakdown, which is concerning,” can we read in the works.
Only a few studies have found out whether participants regained the lost weight at the end of the fast. In one of them, the volunteers regained in three months everything they had lost during a five-day water fast. In two other cohorts, only a small portion of the lost weight was regained.
Water fasting: metabolic benefits that disappear quickly
The authors also observed that water fasting led to a strong increase in circulating ketone bodies, namely alternative substrates for the energy supply of many tissues, such as the brain, heart or skeletal muscles. Another finding: systolic and diastolic blood pressure decreased steadily with prolonged fasting.
“While some trials demonstrate lower LDL cholesterol and triglycerides, others show no benefit. With respect to glycemic control, reductions in fasting blood glucose, fasting insulin, resistance to insulin and glycated hemoglobin (HbA1c) have been observed in adults”, the team said. These metabolic benefits disappeared shortly, three to four months, after the end of the water fast, according to the researchers.
Regarding adverse effects, headaches, insomnia and hunger have been reported in some studies. “Water fasting appears to be a moderately safe dietary therapy that can produce clinically significant weight loss over a few days or weeks. However, the ability of these protocols to produce lasting improvements in metabolic markers merits further study”concluded the scientists, who encouraged people wishing to lose weight to turn to intermittent fasting instead.
