Study: Alternate-Day-Fasting Diets Aren’t Much More Effective Than Counting Calories

In a time when colonics and cleanses seem to be the norm, it comes as no surprise that alternate-day-fasting diets are increasing in popularity. Yet, a new study found that fasting every other day isn’t actually that much more effective for weight loss than simply restricting your daily calorie consumption. On top of that, fasting regimens are way harder to stick with.

Published in the journal JAMA Internal Medicine, the new study from the University of Illinois at Chicago notes that alternate-day fasting has become a popular weight-loss option in recent years, particularly for obese patients who find daily calorie restricting difficult to sustain. A team of researchers therefore set out to determine whether fasting every other day was any more effective than simply limiting a person’s daily caloric intake, especially in regards to weight loss and maintenance. The researchers recruited 100 overweight or obese adults — 86 of whom were women — and randomly assigned them one of three diets: Eating normally, counting their calories each day, and alternate-day fasting.

For the first month, all the participants ate their usual amount, and then spent six months sticking with the diet they were assigned to follow. Those who followed the fasting regime consumed only 25 percent of their normal daily caloric intake every other day — and 125 percent of their normal diet on their alternate “feast” days. Meanwhile, those who were tasked with counting their calories consumed 75 percent of their usual caloric intake each day.

At the end of the study period, the weight loss observed by those in the alternate-day-fasting group wasn’t much different (6 percent) than those in the daily calorie-restriction group (5.3 percent). Furthermore, the drop-out rate of participants in the alternate-day-fasting group was a lot higher than those in the calorie-restriction group — 38 percent compared to 29 percent. “We found that around half the people in the alternate-day-fasting group had a hard time sticking to it,” study co-author Krista Varady told the Guardian.

The study authors noted that the results were limited in that only 69 percent of participants (of an already small group) ended up completing the study. But they also noted that the findings suggest that when it comes to dieting, there’s no one-size-fits-all approach. “Some people can stick to alternate-day fasting better, some people can probably stick to calorie-restriction way better,” Varady told the Guardian. “People just need to figure out which one is better for them.”

Fasting Every Other Day Isn’t the Best Way to Lose Weight