Scientists tested popular intermittent fasting — the result surprised

A six-month study involving 196 overweight adults found that the 16:8 intermittent fasting schedule led to an average weight loss of 4.6% (about 4.3 kg), while the milder 12:12 schedule resulted in only a 1.5% reduction. Researchers noted that the 8-hour eating window naturally limits high-calorie snacking, but unexpectedly did not affect blood pressure.

Scientists at the University of Illinois at Chicago, led by Dr. Krista Varady, conducted a six-month study involving 196 overweight or obese adults with metabolic syndrome. Participants were divided into three groups: the 16:8 schedule (eating within an 8-hour window, e.g., 12:00 PM to 8:00 PM), the 12:12 schedule (eating within a 12-hour window), and a control group with no restrictions. No one counted calories—only the timing of meals changed. Results showed that participants on the 16:8 schedule lost an average of 4.6% of their body weight (about 4.3 kg), while the 12:12 group lost only about 1.5%, and the control group saw virtually no changes. Researchers explained that the 8-hour window naturally limits opportunities for high-calorie evening and nighttime snacking. The 16:8 schedule also showed a slight improvement in fasting glucose levels and insulin sensitivity, though the difference between the fasting groups on these measures was small. An unexpected finding was the lack of significant reduction in blood pressure with the 16:8 schedule, despite weight loss. Researchers believe that to affect blood pressure, one would need to lose more than 5–10% of body weight or change their diet. Most people tolerate the 16:8 schedule well, but it is not recommended for those with eating disorders, during pregnancy, or when taking medications that require a strict eating regimen.