The Line Between Intermittent Fasting and Eating Disorders

Written by Morgan Abercrombie, Intern at HNC

Intermittent fasting, or IF, is described by its proponents as an eating pattern where you eat all your meals within a designated time frame. Rather than dictating what you can and can’t eat, IF instead tells you when you can and can’t eat. 

For someone following intermittent fasting, fasting can range from a 12 to 22 hour daily fast or can be full days of fasting alternated with normal days of eating. While said to not inherently be a form of caloric restriction and eating less, it restricts the times in which a person can eat, which leads them to eat less often. Many people utilize this diet to lose weight in a way that’s “easier” than traditional dieting. Proponents and research claim that IF leads to lower insulin levels, fat being utilized as fuel for the body, and an increase in the gut’s time to rest.

However, restricting the time in which you eat makes it difficult for your body to get the energy it needs daily for normal functioning. Fasting may work in the short term for weight loss, but it can also lead to serious long-term physical and psychological problems.  

Becoming obsessed with weight loss, placing rules around food and meals, or dieting can lead to disordered eating. The intermittent fasting mindset, with its many rules set around eating, can create an unhealthy attitude toward your own body, eating, and food overall. Studies have also shown that dieting is the most important predictor of developing an eating disorder. 

Intermittent fasting has aspects that resemble both anorexia nervosa or binge eating disorder. How exactly?

Intermittent fasting results in someone ignoring their body’s natural hunger cues and eating in only predetermined windows, ignoring their hunger outside of those windows. Also, choosing to follow it generally begins with someone trying to become “healthier,” i.e., losing weight. Individuals with anorexia nervosa ignore their body’s natural hunger cues to eat as few calories as they can throughout the day. This often includes extended fasting and abnormal mealtimes and portion sizes. They are preoccupied with weight, calories, food, and dieting, and often will avoid social situations that involve food, much like individuals who intermittently fast trying to maintain their fasting window.  

On the other hand, intermittent fasting can lead to a person consuming an extremely large meal to try and get all of their calories in one sitting. This also causes them to ignore their hunger cues, as they must eat past the point of fullness to get in an adequate amount. Binge eating disorder generally manifests as eating a larger amount of food in a certain time frame than most people would eat in that same window. This mirrors intermittent fasting significantly. IF essentially leads to bingeing due to the increased hunger during the fasting window. Several studies have found an association between fasting many hours of the day and an increased risk of developing episodes of overeating and binge eating. 

Furthermore, intermittent fasting can lead to a binge-restrict cycle. This can manifest as an individual bingeing on large quantities of food, feeling guilty, returning to their fasting to negate the binge’s effects, developing extreme hunger, and then bingeing again. The cycle will just repeat itself unless there is an intervention. 

Also, IF can also be used to hide an eating disorder, even one without a neat little diagnosis like anorexia nervosa or binge eating disorder. Not all eating disorders present in a typical way and following IF could be a result of an EDNOS (eating disorder not otherwise specified). Disordered eating can hinder a person’s ability to get important energy, protein, vitamins, and minerals necessary for a happy, healthy life. 

Essentially, intermittent fasting normalizes eating disorder behaviors, allowing those who are suffering from one to claim that the reason they fast or binge at one meal is due to intermittent fasting. 

Upon doing further research into ED treatment, CBT-E, or enhanced cognitive behavior therapy, is the type of therapy used to treat binge eating disorder (and others) and is based on the theory that delayed eating and having extreme and rigid dietary rules in place lead to binge-eating episodes. The whole point of this type of therapy is to help someone have regular eating patterns, specifically three meals and two snacks per day with no eating in the intervals between. Eating in this way also helps to restore the body’s natural hunger cues. 

The success of this theory in treating binge eating proves that regular eating is the most important part of healing from this type of eating. Basically, it’s healthier to eat normal meals than it is to restrict and intermittently fast. 

There is a lack of evidence to justify intermittent fasting as an eating pattern that has better health benefits than a regular eating pattern that incorporates overall healthy habits. Instead, intermittent fasting can lead to developing overeating and binge eating. Most of the current research that exists about intermittent fasting has been done in animals. The trials done in humans have lasted no longer than a year and do not show a long-term intervention and follow-up period. That’s not a lot in terms of human-specific research. For any medical professional, it would be inappropriate to recommend intermittent fasting as a healthy eating practice. 

To eating disorder health professionals, intermittent fasting is just a disordered eating pattern rebranded as “wellness culture.” Yes, there are some scientifically proven health benefits, but there is also evidence that it can lead to eating disorders due to abnormal eating patterns. The health benefits are also only seen in moderate fasting cycles, specifically 12-36 hours. 

Let’s remember that everyone fasts naturally during our sleep periods, hence why we call our first meal of the day breakfast or break-the-fast. The amount of time we fast nightly can change daily based on our schedules and hunger cues. For intuitive eaters, there is no set schedule. Instead, they allow their body’s cues to guide their eating schedule. This is the time that our gut is allowed to rest, and it is enough for a healthy individual. 

Ultimately, if you aren’t hungry till midday, and often don’t eat in the morning, that’s fine. But if you do like to eat breakfast and think you should skip it to “be healthier,” then don’t let the latest trends cause you to ignore your natural hunger cues in hopes of losing weight.

Our bodies are smart and know what we need. Listen to them. We respect people’s autonomy to do what they choose to do with their bodies. But we also believe that balanced eating is best for everyone to nourish themselves and heal their relationships with food. 

Resources:

EmilyProgram. Ask A Dietitian: Does Dieting Lead To Eating Disorders? [Video]. YouTube. https://www.youtube.com/watch?v=sYIvwlwlfl4&t=40s. Published 15 Feb 2019. Accessed 26 Jun 2021. 

Golden NH, Schneider M, Wood C; COMMITTEE ON NUTRITION; COMMITTEE ON ADOLESCENCE; SECTION ON OBESITY. Preventing Obesity and Eating Disorders in Adolescents. Pediatrics. 2016;138(3):e20161649. doi:10.1542/peds.2016-1649

Harvie M, Howell A. Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence. Behavioral Sciences. 2017; 7(1):4. https://doi.org/10.3390/bs7010004 

Stockman, MC., Thomas, D., Burke, J. et al. Intermittent Fasting: Is the Wait Worth the Weight?. Curr Obes Rep 7, 172–185 (2018). https://doi.org/10.1007/s13679-018-0308-9