Is This the Fad Diet That Really Works? (Spoiler: It’s Not)

You've surely heard about intermittent fasting. But have you heard about its negative consequences, including links to eating disorders?


Fad diets have been around since the early 1900s, and a lot of the time they’re considered “fads” or short-lived because they are quite dangerous. This includes a current fad diet: intermittent fasting.

Intermittent fasting is a diet that consists of recurring eating patterns where no or few calories are consumed over a variety of different periods ranging from eight hours to several days. For example, there is the 5:2 method in which five days are normal eating days while the other two days are reduced caloric intake days.

In the media, intermittent fasting promises weight loss, muscle retention, lower blood pressure, and lower oxidative stress. All of these factors make intermittent fasting very enticing for the general public, especially because it promises sociocultural “ideal” body norms: meaning low body weight and more muscle.

However, what the media fails to mention is that a lot of the studies reporting “positive” intermittent fasting outcomes are conducted on obese mice or with participants who are clinically overweight or obese. These studies also leave out the fact that fasting can be detrimental to one’s physical health if they are already lean, and to people of all shapes and sizes’ mental health. Specifically, fasting has been demonstrated to be a risk factor for eating disorders, especially among young individuals.

To this end, a new study set out to explore the associations between intermittent fasting and eating disorder behaviours and psychopathology in young Canadians. The study was led by Kyle Ganson, an assistant professor of Social Work at the University of Toronto, and published in Eating Behaviors.

Almost 3,000 young adults (16 to 30 years old) from around Canada reported their engagement in intermittent fasting over the past 12 months and 30 days, as well as completed eating disorder behaviour and psychopathology questionnaires.

The results demonstrated that commitment to intermittent fasting was associated with many eating disorder behaviours — however, they differed across genders.

For example, women who reported intermittent fasting were significantly associated with all eating disorder behaviours (i.e., overeating, loss of control, binge eating, vomiting, laxative use, compulsive exercise, and fasting), while men were significantly associated with compulsive eating, fasting, and vomiting. Transgender and gender non-conforming people were significantly associated with fasting behaviours. All gender groups who engaged in intermittent fasting had significantly higher eating disorder psychopathology scores.

Nonetheless, the current study’s findings suggest that young Canadian adults who engage in intermittent fasting are highly likely to demonstrate eating disorder behaviours and eating disorder psychopathology. Unfortunately, eating disorders behaviours and psychopathology can lead to full-threshold eating disorders which can cause deleterious psychological and physical outcomes to an individual.

A big takeaway from this study is that intermittent fasting may not be all that it is presented to be in the media. Rather than referring to a pop culture article for diet information, a better course of action may be to read peer-reviewed research on the diet and/or ask your doctor about the diet before committing to it.

In sum, be conscious of where your information about diets is coming from. As it has been demonstrated time and time again, diets presented in the media and diet culture can often cause more harm than good.

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Alexandria (Alex) Samson is a PhD student in the Department of Psychology at the University of Toronto. She completed her BSc in Neuroscience from Dalhousie University. Alex is a strong believer in open science and is passionate about making scientific research accessible to all audiences.