Humanity is undergoing a significant physical change. Since 1990, obesity rates have more than doubled among adults and quadrupled among teenagers, according to the World Health Organization (WHO). Currently, one in eight people worldwide is obese, and nearly half of the global population is overweight. This rise is mainly due to sedentary lifestyles and unhealthy diets high in junk food.
Three months ago, WHO’s director general, Tedros Ghebreyesus, highlighted the importance of losing weight to reduce risks of cancer and heart disease. He urged people to exercise regularly and adopt healthy diets without alcohol or sugary drinks. Now, an analysis of 100 medical studies supports a popular approach: intermittent fasting.
The study looks at three types of intermittent fasting: eating every other day, fasting for two consecutive days each week, or skipping one meal daily to fast for about 16 hours. This analysis, which includes over 6,500 people, finds that these fasting methods provide benefits similar to traditional diets that focus on reducing food intake. The study shows comparable effects on body weight and on lowering key health risks like blood pressure and blood sugar. It was published Thursday in the medical journal The BMJ.
Among the fasting methods, alternate day fasting stands out. It leads to greater weight loss than traditional calorie-restricted diets, with about 1.3 kilograms (2.9 pounds) more weight loss after 12 weeks. This method also reduces bad cholesterol more than simply skipping meals. Earlier research showed that alternate day fasting can help people lose up to 6 kilograms (13.2 pounds) in 12 weeks.
Dr. Jordi Salas Salvadó, a nutrition professor at Rovira i Virgili University in Spain and a co-author of the study, says these fasting methods are not necessary for those who already have a healthy weight. He adds, “These results do not mean everyone who is obese should start intermittent fasting. It’s another option, especially for people tired of traditional diets. Professionals can safely recommend it.” He also shares his personal view, saying he has normal weight and has never practiced intermittent fasting but sometimes skips dinner if he’s not hungry.
The study’s lead author, nutritionist John Sievenpiper from the University of Toronto, points out that losing weight helps reduce chronic diseases like type 2 diabetes and heart disease. The analysis covers studies from 24 countries, including Spain, Mexico, and the United States. However, the authors note some limitations: the participants varied widely, making comparisons harder, and the average follow-up time was only about 12 weeks. They stress that longer studies are needed to confirm these findings.
Dr. Salas Salvadó concludes, “We already knew traditional calorie-restricted diets work in the short and long term. Now we also know intermittent fasting works, at least in the short term. It’s another useful strategy.”
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