New Research: Intermittent Fasting Might Not Be As Safe as We Thought

By UNIVERSITY OF TORONTO JANUARY 1, 2023

Intermittent fasting is a popular dietary trend that involves cycling between periods of eating and fasting. It is believed to have various health benefits such as weight loss, improved insulin sensitivity, and reduced inflammation.

The popular dietary trend has been linked to dangerous eating disorder attitudes and behaviors among adolescents and young adults.

A recent study published in the journal Eating Behaviors has shed light on the potential negative effects of intermittent fasting, a popular dietary trend in which people abstain from eating for more than 8 hours at a time. Although intermittent fasting is often promoted as a way to improve health and control or lose weight, few studies have examined its potential risks.

According to the study which analyzed data from over 2,700 adolescents and young adults in Canada, intermittent fasting was found to be linked to disordered eating behaviors in women, including binge eating and compensatory behaviors such as vomiting and compulsive exercise. Men who practiced intermittent fasting were also more likely to report compulsive exercise.

The prevalence of intermittent fasting behaviors among adolescents and young adults was notable. In total, 47% of women, 38% of men, and 52% of transgender or gender non-conforming individuals reported engaging in intermittent fasting in the past 12 months.

“Given our findings, it is problematic how prevalent intermittent fasting was in our sample,” says lead author Kyle T. Ganson, Ph.D., MSW, assistant professor at the University of Toronto’s Factor-Inwentash Faculty of Social Work.

In all three groups, participants reported an average of 100 days where they engaged in intermittent fasting over the past 12 months.

“The associations found between intermittent fasting and eating disorder behaviors are particularly salient, given the significant increase in eating disorders among adolescents and young adults since the start of the COVID-19 pandemic,” says Jason M. Nagata, MD, MSc, assistant professor at the University of California, San Francisco, and a study co-author.

The findings provide a warning to healthcare professionals about recommending intermittent fasting as a means of weight loss, as it may facilitate eating disorder attitudes and behaviors.

“We need more education in healthcare settings and greater awareness in popular culture, including social media, of the potential harms of intermittent fasting,” says Ganson. “At this point, the proposed benefits are still unclear and unsupported by research, and the potential harms are becoming clearer.”