Binge-eating Disorder VS Bulimia Nervosa: 7 Key Differences You Need To Know

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When you hear the term eating disorder, there’s a good chance you’re either thinking of bulimia nervosa or binge-eating disorder.

There’s probably a good reason for this; both are the most common among all of the eating disorder subtypes and are often depicted in television and the media

However, bulimia nervosa and binge-eating disorder aren’t the same; they’re actually very different. They have different underlying symptoms, affect different people, and show their own unique course.

Therefore, it’s important to not conflate the two because it could do more harm than good. 

This article will help you better understand how bulimia nervosa and binge-eating disorder differ from each other.

What is Bulimia Nervosa and Binge Eating Disorder? 

Before diving into differences between the two, it’s necessary to first define these eating disorders. 

Bulimia nervosa is an eating disorder characterized by recurrent episodes of binge eating in combination with inappropriate purging/compensatory behaviours, and an overvaluation with weight and shape. 

Let’s break this definition down a little further, step by step.

“Recurrent” in this instance refers to once weekly, on average, over the past 3 months. 

“Binge eating” refers to overeating where there is a loss of control.

Inappropriate purging/compensatory behaviours can range from things like self-induced vomiting, abusing laxatives, fasting for long periods, or taking diuretics. 

And an overvaluation with weight and shape means that the person judges their self-worth almost entirely on how they look or what they weigh. 

Now, let’s turn our attention to binge-eating disorder. 

Binge-eating disorder is a condition characterized by recurrent episodes of binge eating in the absence of purging or compensatory behaviours. 

With this definition, you’ll see that while there are some important similarities (i.e., both involve binge eating), there are also crucial differences, like the absence of purging and an overvaluation with weight and shape. 

These features are what differentiates a bulimia nervosa diagnosis from a binge-eating disorder diagnosis.

However, they are not the only differences we see. 

Let’s take a deeper dive into 7 other noteworthy differences. 

The 7 Main Differences Between Bulimia Nervosa and Binge Eating Disorder 

1. Binge Eating Triggers 

We know that binge-eating disorder and bulimia nervosa both involve episodes of binge eating.

However, there’s evidence to suggest that the underlying triggers may differ between the two disorders¹ Fairburn, C. G. (2008). Cognitive behavior therapy and eating disorders. Guilford Press. .

In bulimia nervosa, the strongest binge trigger we typically see is a dietary lapse, which essentially occurs when one perceives that they’ve broken a self-imposed food “rule”. People with bulimia nervosa typically diet in an extreme fashion, and inevitable dietary transgressions tend to trigger an episode of binge eating (also referred to as the “what-the-hell-effect”).

In binge-eating disorder, however, the strongest binge trigger we typically see is a sudden change in mood states. People with binge-eating disorder are more likely to resort to food when something goes wrong in their life because food/eating can help the person cope better with the adverse situation.

Now, this isn’t to say that people with Bulimia Nervosa aren’t triggered by negative mood states, or that people with binge-eating disorder aren’t triggered by dietary lapses. 

Instead, it’s that these specific triggers tend to be stronger for one over the other.

2. Body Mass 

It should come as no surprise that bodyweight differs between bulimia nervosa and binge-eating disorder. 

People with Bulimia Nervosa typically fall within the “healthy” BMI range, while people with binge-eating disorder typically fall within the “overweight/obese” BMI range.

For example, research shows that 1 in 4 people with binge-eating disorder meet the criteria for “obesity”, an estimate that’s far lower in bulimia nervosa ² Heal, D. J., & Smith, S. L. (2021). Prospects for new drugs to treat binge-eating disorder: Insights from psychopathology and neuropharmacology. Journal of Psychopharmacology, 02698811211032475  

The reason for this difference is clear – people with bulimia nervosa compensate for the excess calories consumed during a binge, whereas people with binge-eating disorder do not compensate. This results in the excess build-up of adiposity in Binge-eating Disorder (but not Bulimia Nervosa). 

3. Illness Course 

One consistent finding we wee is that recovery is far easier in binge-eating disorder than bulimia nervosa.

We’re not entirely sure why this is the case, but it’s something that consistently shows up in research.

Without any treatment, we see that, in the very long-term, 70% of people tend to fully recover from binge-eating disorder compared to only 20% of people with bulimia nervosa ³Fairburn, C. G., Cooper, Z., Doll, H. A., Norman, P., & O’Connor, M. (2000). The natural course of bulimia nervosa and binge eating disorder in young women. Archives of General Psychiatry, 57(7), 659-665.

These differences may be a result of the complex psychopathology experienced in Bulimia Nervosa relative to binge-eating disorder, but this is something yet to be proven. 

4. Sex Distribution

There are clear sex differences in the prevalence of these disorders.

In binge-eating disorder, there’s a far more equal sex distribution. In some studies, we see an almost equal ratio of males and females with Binge-eating Disorder.

However, in bulimia nervosa, we see a different pattern; females with bulimia nervosa outnumber males with bulimia nervosa on a 1:8 ratio in other studies ⁴ Hoek, H. W. (2016). Review of the worldwide epidemiology of eating disorders. Current opinion in psychiatry, 29(6), 336-339.

Again, the reasons for this discrepancy isn’t entirely clear, but males seem to be far more affected by Binge-eating Disorder than they are Bulimia Nervosa.

5. Body Image Distortions 

Unlike Bulimia Nervosa, which requires the presence of an overvaluation with weight and shape, there are no diagnostic criteria related to body image disturbances in binge-eating disorder.

While we usually see that people with bulimia nervosa have a far more distorted view of their body (that is, they are more dissatisfied, more preoccupied, have a greater fear of weight gain, and engage in more obsessive body checking behaviour), it’s also important to recognize that body image affects Binge-eating Disorder.

A substantial proportion of people with binge-eating disorder overvalue their body image, are extremely unhappy about their figure, and report severe levels of feeling fat ⁵ Grilo, C. M. (2013). Why no cognitive body image features such as overvaluation of shape/weight in the binge eating disorder diagnosis?. International Journal of Eating Disorders, 46(3), 208-211 .

Given this, it’s now considered appropriate to characterize people with binge-eating disorder on the basis of how severe their body image distortions are, including a mild, moderate, severe, and extreme level. 

6. Prior History

People tend to move from one eating disorder to another. 

In other words, it’s not uncommon for someone to initially have bulimia nervosa and then later develop anorexia nervosa. 

This is what we call “diagnostic migration”. 

We see a different pattern of diagnostic migration among people with bulimia nervosa and people with binge-eating disorder.

Compared to binge-eating disorder, people with bulimia nervosa are far more likely to report a history of anorexia nervosa. 

Furthermore, it’s not common for people to migrate from binge-eating disorder to bulimia nervosa, but it is common for people to migrate from bulimia nervosa to binge-eating disorder ⁶ Castellini, G., Sauro, C. L., Mannucci, E., Ravaldi, C., Rotella, C. M., Faravelli, C., & Ricca, V. (2011). Diagnostic crossover and outcome predictors in eating disorders according to DSM-IV and DSM-V proposed criteria: a 6-year follow-up study. Psychosomatic medicine, 73(3), 270-279. . 

The shift in eating disorder diagnosis seems to suggest that there are similar underlying psychopathologies that are driving these different eating disorders. 

7. Different Treatment Options 

Some treatments are more effective for bulimia nervosa than for binge-eating disorder, and vice versa. 

Self-help approaches are very effective for binge-eating disorder, but often do little to help people with Bulimia Nervosa. 

Similarly, psychotherapy that focuses on addressing interpersonal conflicts seem to work very well for binge-eating disorder, but don’t work as well (or take a long time for work) for people with Bulimia Nervosa. 

On the other hand, people with bulimia nervosa typically require intensive, face-to-face treatments like cognitive-behavioural therapy, whereas people with binge-eating disorder can do well with more remote treatments, like digital therapies. 

There are also some medications that can help people with Binge-eating Disorder, but don’t seem to work as well Bulimia Nervosa, like fluoxetine or sertraline. 

They’re Different, So What?

Ideally, you’ve now developed an understanding of how bulimia nervosa and binge-eating disorder differ. 

As you’ve come to learn, while there are indeed important differences between the two, there are also many similarities that warrant comment.

Both seem to share similar underlying risk factors (e.g., childhood bullying, sexual abuse, certain personality traits), affect the psychological functioning of the person to a similar extent, and cost the healthcare system an enormous amount of resources. 

Both bulimia nervosa and binge-eating disorder are important eating disorders that are not to be ignored.