In a small study published in the American Journal of Clinical Nutrition, 16 obese people followed an intermittent fast: eating normal meals one day, then on the next day having only one meal (lunch), which delivered 25 percent of the calories needed to maintain their weight and activity level. “I expected that they’d overeat on the non-fasting day,” says study author Krista Varady, PhD. But they didn’t, and after eight weeks, the dieters lost 10 to 30 pounds.
Alternate day fasting (ADF) reduced the subjects’ overall calorie intake. “When participants woke up and made a big breakfast, they couldn’t ?nish it—possibly because their stomachs had shrunk,” Varady theorizes. Ongoing research suggests ADF might also help moderately overweight people.
But this regimen is controversial, and it’s not for everyone, notes Keri Gans, RD, of the American Dietetic Association. People with health issues like diabetes or a history of eating disorders should steer clear of ADF, and, she says, no one should try it without a doctor’s OK. If you’re interested, consider consulting a dietitian who can customize your meals.