Alternate-day fasting and cardiometabolic risk factors: systematic review

Researchers combined results from several studies of alternate-day fasting, where people ate very little one day and normally the next. The participants were adults, many with overweight or obesity, and the studies usually lasted only a few weeks or months. Alternate-day fasting generally helped people lose weight and lowered some heart-risk measures, including blood pressure, triglycerides, a type of blood fat, and LDL cholesterol, often called bad cholesterol. It did not consistently improve blood sugar or beat ordinary calorie restriction, meaning simply eating fewer calories each day.

What this means for you: Alternate-day fasting may help with weight loss, but it does not appear clearly better than other ways to eat fewer calories. The short studies and differences between them mean this is not a strong reason to buy a fasting program or product.