When Does Intermittent Fasting Become Disordered Eating?

We'll venture a guess that you've heard a lot about the benefits of intermittent fasting (IF) lately. The buzzy way of eating, which involves periods of fasting, can lead to fat burn, weight loss, better glucose control and lower cholesterol and blood pressure, according to the University of Michigan.

All of that probably sounds great if you've been looking for a way to lose weight without counting calories or sticking to a kale-only diet. But if you're wondering whether an eating pattern that encourages abstaining from food for hours to days at a time ventures into disordered eating territory, you're certainly not alone.

The short answer is that it's too soon to say for sure whether IF is a slippery slope to an eating disorder. One 2017 review published in ​Behavioral Sciences​ noted that there have been concerns that it could lead to erratic eating patterns, bad moods and binging. But the limited number of studies that have been done to date don't indicate a link between IF and disordered eating.

Many professionals who work with patients with eating disorders, however, disagree. Here's what you need to know about the potential dangers of IF.

By definition, IF means that followers fast for a specified amount of time. There are a few different approaches, such as the 5:2 diet, which calls for eating normally five days a week and fasting for two, and the 16:8 method, which involves fasting for 16 hours each day and eating all of the day's calories during the remaining eight-hour window.

That in and of itself is technically considered disordered eating because, as Colleen M. Neumann, PsyD, MSW, a licensed clinical psychologist, explains, creating rules around how foods can be eaten is one of the hallmark behaviors.

​Read more:​ You Are When You Eat? How Intermittent Fasting Affects Weight Loss

"If you're narrowing the timeframe in which you're allowed to eat and completely ignoring your hunger cues outside of that timeframe, it could be an unsafe approach, especially for those in eating disorder recovery," says Samantha DeCaro, PsyD, an assistant clinical director at The Renfrew Center of Philadelphia.

It can also become dangerous if the designated eating time is used to overconsume. Neumann says that can happen as a result of ignoring hunger. Your brain might enter 'famine' mode in the hours before the fast ends, and by the time you finally give yourself permission to eat, you might be in 'feast' mode and eat more than you need to in a short period of time. If that's how you break every fast, that could qualify as binge eating disorder, which the National Eating Disorders Association defines as recurrent episodes of eating large quantities of food.

"What makes IF different from disordered eating is the intent and rationale for following it."

Not sure whether your approach to IF is concerning? Consider your reasons for choosing IF in the first place. "What makes IF different from disordered eating is the intent and rationale for following it," says Marjorie Nolan Cohn, RDN, owner of MNC Nutrition.

Perhaps you're opting to follow the diet because you have diabetes and want to tap into the insulin-resistance benefits, or you have obesity and are fasting under doctor surveillance. That's not as worrisome as choosing IF in order to severely restrict calories or to cover up an underlying eating disorder. For example, ask yourself if you're practicing IF because it gives you a socially acceptable excuse to, say, skip a meal with friends, DeCaro says.

Another way to determine whether your approach is healthy is to think about how you'd react if you fell off the wagon and ate outside the designated window. Would it make you feel bad about yourself? Would you view yourself as a failure? These types of feelings could also be a sign that IF has crossed into disordered eating territory, Neumann says.

• Finally, DeCaro says to keep an eye out for other warning signs of an eating disorder, including:
• An intense fear of weight gain
• Over-exercising
• Feeling guilty after eating
• Stepping on a scale multiple times a day
• Using the bathroom immediately after meals
• Abusing laxatives
• Skipping meals
• Eating in isolation

If any of this sounds like you, call the National Eating Disorders Association helpline at 800-931-2237 or reach out to a professional for help.

​Read more:​ 12 Dos and Don'ts of Intermittent Fasting

As you may have gathered, if you have a history of eating disorders, it's a good idea to avoid IF altogether, according to the Harvard T.H. Chan School of Public Health. "While IF may be fine for some people, for those with a history or at higher risk of disordered eating, the act of IF may trigger something deeper psychologically, which can lead to a serious eating disorder," Cohn says.

If you don't have that background and decide to pursue IF, it's still smart to consult a professional first. Cohn suggests speaking with a registered dietician or a therapist about your reasons for wanting to try IF to ensure you're approaching it for a true health-based reason. A dietitian will also be able to help you create a safe meal plan and advise you on how best to break your fast.

And, as you start your IF journey, be on the lookout for the negative feelings and emotions mentioned above. If it feels like you may not be in it for the right reasons, let yourself quit. One study published June 2018 in ​Current Obesity Reports​ noted that dropout rates for studies involving fasting can be as high as 40 percent. IF is notoriously difficult to stick to, so there's no shame in throwing in the towel and opting for a more balanced approach to eating.

​Read more:​ How to Find the Best Weight-Loss Diet for You