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Bulimia Nervosa vs Purging Disorder – Similarities and Differences

There are many different ways that disordered eating can manifest. Most of the conversation focuses on anorexia, but eating disorders are far more complex. There are diagnostic criteria for conditions such as binge eating disorder outlined in the DSM-V (the statistical manual psychologists use to diagnose mental health conditions). There are also conditions not currently considered “disorders,” but are widely recognized by therapists that specialize in eating disorders. For example, orthorexia.

There are two eating disorders that both have clear diagnostic criteria and a lot in common, but are considered different conditions. One of those conditions is bulimia nervosa (usually shortened to bulimia) and the other is purging disorder. Both are extremely similar, but knowing the difference is important for both the patient and the therapist.

Who We Are – Flourish Psychology in New York City

Flourish Psychology is a team of therapists in Brooklyn that specialize in eating disorders and eating disorder treatment. It is led by Dr. Sadi Fox, a psychologist in NYC that works extensively with eating disorder patients, including celebrities and other high-profile clients.

Her work with eating disorders has been featured in several papers and news websites, such as Huffington Post, and Flourish Psychology is her private practice, where she treats patients in Brooklyn, NYC, and the rest of New York state along with her team of amazing therapists and counselors.

What is Bulimia?

Bulimia nervosa is one of the most common eating disorders, affecting ~1 to 2% of the population in their lifetime, possibly more, with women (both cis and trans) experiencing bulimia at a 3x higher rate than men. Bulimia is, in many ways, a combination of two disorders. It is characterized by:


Binge Eating – To be diagnosed with bulimia, patients need to experience many episodes of binge eating per week, sometimes multiple times a day.


Purging – After binge eating, a person then purges the calories, typically through vomiting or laxatives. Some people may purge in other ways like exercise, but this is less common.

Woman with OCD in NYC washing hands

Binge eating is necessary for a bulimia diagnosis, and – in many ways – a trigger for the purging. We’ll discuss that more in a moment.
Bulimia can theoretically lead to weight loss, but often doesn’t. Most people with bulimia maintain the same body weight or gain weight. That is because the body starts to process calories immediately upon consumption, which means that by the time the person purges, they have already processed a large quantity of the calories they consumed while binging.

Although bulimia is related to body image issues, it is a misconception that people with bulimia lose weight. Many TV shows often show supermodels as maintaining their body weight through purging, and call the disorder bulimia, but bulimia is usually not effective for weight loss and not entirely related to a desire for a thinner body.

However, despite processing some calories, bulimia can be deadly. It causes electrolyte imbalances, heart issues, and many other problems that can result in severe health consequences.

What is Purging Disorder?

Purging disorder is, as the name implies, bulimia without the binge eating. People with purging disorder eat either “normal” sized meals or undersized meals, and then purge what they ate through self-induced vomiting or laxatives.
Because an individual with purging disorder eats a normal or below normal quantity of food before purging, purging disorder results in extreme caloric restriction similar to anorexia, and can lead to significant and potentially deadly weight loss. Research estimates that as many as 5% or more of adults with purging disorder will die from the condition, which compares to other forms of extreme starvation, like anorexia.

What Are the Similarities of Bulimia and Purging Disorder?

Both bulimia and purging disorder can appear to be similar conditions and do have a lot in common. Both are eating disorders that are partially or entirely fueled by a desire not to gain weight. Both relate to body-image issues and can be triggered by trauma, anxiety, depression, and other mental health conditions.

And of course, both involve purging.

At a glance, it’s easy to see why many people call purging disorder “bulimia,” because the cornerstone of the condition – the purging – makes it seem like they’re loosely the same condition. But there are actually some very key differences between them, and reasons that purging disorder may actually be closer to anorexia than bulimia.

What Are the Differences Between Bulimia and Purging Disorder?

Bulimia is far more common than purging disorder alone. That is a fact that can surprise people, because media representations of bulimia rarely show the binge eating component. It also raises questions: if both types of eating disorders are related to body image issues, why would bulimia be more common in those that binge eat than those simply trying to lose weight?

To understand this, we have to look not at purging disorder or bulimia, but at binge eating disorder.
Binge eating disorder is the most common eating disorder, even more so than anorexia and bulimia. People with binge eating disorder feel a total loss of control over food, causing them to eat excessive amounts of food in ways that cause shame, weight gain, and poor health.

It is that shame and fear of weight gain that leads to purging. Rather than a desire to maintain a low body weight, which is what tends to fuel anorexia, a person binge eats and then feels so much shame and distress over this loss of control that they try to purge it out so that they do not gain excessive amounts of weight. Since many people that binge eat also feel fairly sick after an episode, it becomes easier to purge it out.

So, while bulimia is associated with purging and the desire for a low body weight, it is really the binge eating that typically triggers the purging response.
Purging disorder is different. Purging disorder occupies a unique space in that it is, as these researchers put it, “not quite bulimia and not quite anorexia.” But people with just purging disorder are usually much more motivated to maintain a low body weight, making it more like anorexia. It is often caused by a desire to lose weight and an unhealthy body image, and – instead of restricting calories altogether – the person chooses to eat some food but then purge the calories before they gain as much weight.

This is what makes purging disorders more dangerous, but also less common. Most people do not enjoy purging, so a person with body image issues and an unhealthy desire to lose weight is more likely to severely caloric restrict than they are to purge. But if the person binge eats, the shame and distress over the binge eating (combined with the feeling of being ill that typically accompanies it) makes purging “easier,” creating the bulimia nervosa cycle.

All Eating Disorders Are Dangerous But Treatable

It is useful to understand the differences between these conditions in order to spot them in yourself or a loved one, and know the proper way to describe them to a psychologist or counselor. But no matter which condition a person has, they need to seek treatment right away. 

Eating disorders are considered the most deadly psychiatric conditions, even more so than clinical depression. Both purging disorder and bulimia can be extremely dangerous, and – no matter which diagnosis the therapist may provide – it is critical that they consider seeking help as soon as possible to start addressing their body image and disordered eating challenges.

But eating disorders do respond very well to therapy, and there are approaches that can help those with eating disorders take back control over their mental health and eating habits once again. These conditions may be different, but they are both treatable for those willing and ready to work with a mental health professional. 

Looking for More Information?

If you are in Brooklyn or NYC and would like to pursue treatment for yourself or a loved one for any type of eating disorder or body image-related issue, please feel free and contact Flourish Psychology. Our remote services are also licensed to provide therapy throughout the entirety of New York State.

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