Researchers from the University of Toronto analyzed data from more than 2700 adolescents and young adults from the Canadian Study of Adolescent Health Behaviors, and found that for women, IF was significantly associated with overeating, binge eating, vomiting, laxative use, and compulsive exercise.
IF in women was also associated with higher scores on the Eating Disorder Examination Questionnaire (EDE-Q), which was used to determine ED psychopathology.
Study investigator Kyle Ganson, PhD, assistant professor in the Factor-Inwentash Faculty of Social Work at the University of Toronto, said in an interview that evidence on the effectiveness of IF for weight loss and disease prevention is mixed, and that it’s important to understand the potential harms of IF – even if there are benefits for some.
“If anything, this study shines light on the fact that engagement in IF may be connected with problematic ED behaviors, requiring health care professionals to be very aware of this contemporary and popular dietary trend, despite proponents on social media touting the effectiveness and benefits,” he said.
The study was published online in Eating Behaviors.
Touted for health benefits
The practice of IF has been gaining popularity partly because of reputable medical experts touting its health benefits. Johns Hopkins Medicine, for instance, cited evidence that IF boosts working memory, improves blood pressure, enhances physical performance, and prevents obesity. Yet there has been little research on its harms.
As part of the Canadian Study of Adolescent Health Behaviors, Dr. Ganson and associates analyzed data on 2,700 adolescents and young adults aged 16-30 recruited from social media ads in November and December 2021. The sample included women, men, and transgender or gender-nonconforming individuals.
Study participants answered questions about weight perception, current weight change behavior, engagement in IF, and participation in eating disorder behaviors. They were also administered the EDE-Q, which measures eating disorder psychopathology.
In total, 47% of women (n = 1,470), 38% of men (n = 1,060), and 52% transgender or gender-nonconforming individuals (n = 225) reported engaging in IF during the past year.
Dr. Ganson and associates found that, for women, IF in the past 12 months and past 30 days were significantly associated with all eating disorder behaviors, including overeating, loss of control, binge eating, vomiting, laxative use, compulsive exercise, and fasting – as well as higher overall EDE-Q global scores.
For men, IF in the past 12 months was significantly associated with compulsive exercise, and higher overall EDE-Q global scores.
The team found that for TGNC participants, IF was positively associated with higher EDE-Q global scores.
The investigators acknowledged some limitations with the study – the method of recruiting, which involved ads placed on social media, could cause selection bias. In addition to this, data collection methods relied heavily on participants’ self-reporting, which could also be susceptible to bias.
“Certainly, there needs to be more investigation on this dietary practice,” said Dr. Ganson. “If anything, this study shines light on the fact that engagement in IF may be connected with problematic ED behaviors requiring healthcare professionals to be very aware of this contemporary and popular dietary trend – despite proponents on social media touting the effectiveness and benefits.”