After one year, researchers found that weight loss was about the same – 6% for those on the alternate-day fasting diet and a little over 5% for those on the daily restricted-calorie diet.
“We thought that alternate-day fasting group would do better. It allows people to have a break from dieting every other day, so we thought their adherence would be better,” explained lead author Krista Varady.
“But it turns out people in both diets lost the same amount of weight,” said Varady. She’s an associate professor of kinesiology and nutrition at the University of Illinois at Chicago.
“People in the alternate-day fasting group were eating more than the 500 calories prescribed on the fast day, but a lot less than the calories prescribed on the feast day. That’s why they lost the same amount of weight,” she explained. However, “people who stuck to the [alternate-day fasting] diet lost 20 to 50 pounds in a year,” Varady added. “It does work for some people.”
In the study, Varady’s team randomly assigned 100 obese people to an alternate-day fasting diet, a conventional diet (25% reduction in calories every day), or no diet at all (the “control” group).
People on the conventional diet were able to stick to their calorie goals better than the alternate-day fasting group, the researchers found. The dropout rates were 38% or the alternate-day fasting group and 29% for the conventional group.
The fasting diet appeared to be safe, Varady noted. On fasting days, people were encouraged to eat a lot of protein because protein makes you feel full, she said.
