Is intermittent fasting disordered eating?

What is intermittent fasting?

Intermittent fasting is a pattern of eating that involves cycling between periods of fasting (not eating) and eating. There are several ways to practice IF, but nearly all impose this type of eating pattern at regular, scheduled intervals. Some people fast for a specific window each day, while others may fast for several days at a time.

People participate in intermittent fasting for a number of reasons, including religious reasons. Recently, the approach has gained popularity as a way to lose or manage weight. When weight loss is the primary goal of IF, the practice can become particularly risky.

Intermittent fasting: Risks vs. benefits

While intermittent fasting has long been practiced as a religious observation, its effects on physical and mental health have not been thoroughly researched until recently.

Much research on the practice is ongoing, and findings so far are mixed.

Psychological impacts of intermittent fasting

Aside from impacting physical health, intermittent fasting may affect mental health.

One study looking at adolescents and young adults in Canada found that 47.7% of females, 38.4% of males, and 52% of transgender/gender non-conforming participants reported engaging in intermittent fasting in the past 12 months. Of those who engaged in the eating behavior, there was a significant association with eating disorder psychopathy or the way of thinking that maintains disordered eating behaviors.⁹

One overlap may be feelings of achievement, pride, and control that some people have reported after engaging in intermittent fasting diets.⁵ When connected to tactics used specifically to lose weight, these emotional responses can help drive eating disorder thoughts and behaviors.

It's possible that intermittent fasting's impact on blood sugar could lead to further psychological effects, including irritability and mood swings.⁵ Low blood sugar, a common effect of fasting, is also associated with anxiety, fatigue, and poor concentration.

Intermittent fasting vs. eating disorders

If you're wondering, "Is intermittent fasting an eating disorder?" the direct answer is no. Eating disorders are complex psychological conditions that involve several interrelated genetic, psychological, and environmental causes and drivers.

Intermittent fasting is better described as a disordered eating behavior, especially as it's used in contemporary dietary trends. People may struggle with disordered eating if they eat for reasons other than hunger and nourishment, and/or they actively deny or ignore their body’s needs based on internal signals of hunger and satiety.

These types of behaviors can be considered "gateways" to full-blown eating disorders, however, especially when they're done explicitly to lose or control weight. When it comes to IF specifically, the rigid schedules and restrictions involved can be especially problematic for promoting thoughts and behaviors associated with eating disorders.

Intermittent fasting and eating disorder risk factors

While intermittent fasting is not technically considered an eating disorder, it's been found to be a risk factor for maladaptive eating behaviors and eating disorders.^6,7 Specifically, there have been connections drawn between intermittent fasting and binge eating disorder and IF and bulimia nervosa.

Those who practice IF are often subject to hunger and are prone to overeat during their "eating" windows, which can cause a sense of guilt about how much has been consumed—a key factor in binge eating disorder—and lead to "compensatory" behavior to make up for the binge, which can develop into bulimia nervosa or other disordered eating patterns.¹

Research shows that previously engaging in IF increases risk for binge eating. Plus, IF decreases the likelihood of practicing intuitive eating—an interoceptive approach to eating where you connect to your body to guide eating, partly through honoring your hunger and fullness cues. This suggests greater disordered eating as a result of IF, which increases risk for an eating disorder.¹⁰

On a deeper level, fasting can deplete tryptophan, a precursor of serotonin. Lower serotonin levels may increase the risk of binge-eating high-carbohydrate food in an attempt to restore these levels.⁷

Intermittent fasting and eating disorders: When to seek help

Not everyone who engages in intermittent fasting meets the criteria for an eating disorder, but there are some indicators that someone’s fasting has progressed to a problematic and potentially dangerous level. These may include:^3,8

• Obsessing with losing weight
• An intense fear of gaining weight
• A distorted body image
• Self-esteem that’s heavily dependent on body shape and weight
• Feeling ashamed, guilty, or distressed after eating
• Eating alone to avoid embarrassment
• Being preoccupied with calories, fat grams, carbohydrates, weight, and more
• Cutting out entire food groups, such as carbohydrates
• Isolating from loved ones
• Frequently checking body size/shape/parts in the mirror and/or difficulty engaging in social experiences due to body checking, or body checking in general 
• Experiencing unpredictable mood changes
• Over-exercising, exercising to compensate for eating, exercising despite recommendations to rest, being unable to take rest days, and/or missing out on important aspects of social life due to the drive to exercise

Many of these signs are emotional or psychological in nature, and that’s frequently what separates intermittent fasting from disordered eating. Moreover, it’s important to consider how a person may feel if they eat during their designated fasting time. If they feel ashamed or view themselves as a failure, this is a sign that their intermittent fasting has become unhealthy.