Here’s a comparison look at bulimia nervosa vs. Prader‑Willi syndrome: two disorders that cause the consumption of enormous amounts of food in a single sitting and all throughout the day.
If you’re familiar with Prader-Willi syndrome (often referred to as PWS), you’ll know that this rare genetic disorder causes the affected person to feel raging hunger no matter how much they eat.
And you probably already know that in bulimia nervosa, the individual has developed this condition of overeating in response to a multi-layered environment, and physical hunger can actually trigger an overconsumption episode.
More on Bulimia Nervosa
In this psychiatric condition there are repeated episodes of binge eating — consuming a large amount of food in a short period (often less than two hours) and feeling a loss of control while doing so, says the American Psychiatric Association.
After a binge, people with BN typically engage in compensatory behaviors to avoid weight gain.
This can include self‑induced vomiting, misuse of laxatives, fasting or very excessive exercise.
This is why many bulimics are of a normal body weight, though some may be a little underweight or a little overweight, says the National Eating Disorders Association.
Many with BN also have a fear of weight gain that’s out of proportion to the normal concern that a health conscious person would have. They also often have a distorted body image.
Bulimia nervosa may seem, on the surface, driven by societal beauty standards.
But this psychiatric condition has deeper roots that are a composite of psychological, social and perhaps differences in brain chemistry.
Someone with BN will continue gorging well past the point of fullness, even to the point of significant stomach discomfort. There is truth to that saying: “Eating one’s feelings.”
What Prader‑Willi Syndrome Is
A woman with PWS strength trains.
PWS is caused by a partial deletion involving paternal chromosome 15.
Somewhere in preschool age, the child with PWS will begin developing a ravenous hunger that persists despite eating three full meals and snacks a day.
Many articles about PWS describe it as “never feeling full,” or something similar, such as, “Their brain can’t tell their stomach when it’s full.”
But fullness isn’t the issue here. It’s constant, intense hunger — believed to be the type of hunger one would feel if having not eaten in several days, such as with someone lost in the wilderness.
Perhaps you’ve read of people stranded in the wilderness who become so hungry that they’ll eat anything, such as insects, leaves and twigs.
A person with Prader-Willi syndrome may very well feel this degree of hunger drive — at all times.
But they can’t give a comparative description of their hunger because they’ve never known what satiation feels like.
Though someone with PWS actually experienced satiation very early in life, this would be too young for them to recollect to a narrative level.
People with PWS are much more likely than someone with BN to become obese because:
- An intense hunger is always present no matter what the food intake.
- They have naturally low muscle tone, which means a slow metabolism.
- The disorder usually comes with a cognitive impairment, rending the individual unable to fully appreciate the gravity of their condition.
The hunger is real and raw, deep and primal, and the overeating is done to combat this physical sensation.
There are no emotions involved, such as in bulimia nervosa.
Comparing Bulimia Nervosa and PWS: Overlaps and Key Differences
Similarity: Both conditions involve serious eating dysregulation.
In BN, it’s binge eating + compensatory behaviors; in PWS, it’s hyperphagia — a continuous or near‑constant, uncontrollable drive to eat and inability to feel any form of satiation.
Also in both cases, a tremendous amount of calories may be consumed over a very short period of time.
Differences: BN is primarily a psychiatric and behavioral disorder. A binge may begin even in the absence of hunger.
Plus, a bulimic person will eat foods that are almost always enjoyed under normal circumstances; often their favorite foods.
They may conjure up some unconventional food combinations if they haven’t had a chance to grocery shop, such as smearing canned cake frosting on a bagel — but what they eat is usually something that tastes good to them.
Due to a normal “hunger center” in their brain (the hypothalamus), they will eventually feel so stuffed and physically drained that they’ll stop eating, with no risk of a stomach rupture.
Despite large quantities of food eaten during a binge, the bulimic sufferer has a normal sensation and regulation of physical hunger.
No matter what their psychological state, a bulimic individual will not eat non-edible items such as dog food, raw flour, a tube of toothpaste or drink a bottle of cooking oil.
In PWS, the hyperphagia comes from hypothalamic dysfunction.
Since the psychiatric components of BN are absent, someone with PWS won’t attempt to vomit food or use other means to reverse the caloric intake, as many are complacent with being even super morbidly obese, likely due to cognitive impairment.
Those with a higher level of intellectual ability would more understand the dangers of obesity and also have self-consciousness of its appearance.
But even then, they’ll still struggle with making a concerted effort to self-manage their food intake.
The hunger could be so hardcore that, when food is locked up (when the patient lives with a caregiver), they may resort to eating non-edibles such as the examples cited above.
They’ve also been known to eat non-food items just to get something down their throat and into their stomach.
When a bulimic is short on food but feels the need to binge, they’ll wait for the next reasonable opportunity for food, such as buying a load of sugary foods from a convenience store or ordering the largest pizza for home delivery.
Someone with PWS, who’s not under supervision, may do this as well.
However, the typical case is that there’s tight supervision (though in many instances the caregiver repeatedly gives in and overfeeds the individual), barring the sufferer from getting food when they want.
Unlike the bulimic, they’ve been known to break into cars to steal visible food; beg people on the street to buy them food; and rummage through garbage cans and eat even spoiled or moldy food.
There are cases in which someone with PWS literally ate themselves to death.
In fact, this is a fear among their loved-ones.
- There is no effective treatment for PWS. Because the hunger originates in a hypothalamic defect, GLP-1 drugs and bariatric surgery would have no effect.
- The only way to control eating in PWS is to lock up food, which many families — and all group homes for PWS patients — do with padlocks and locked doors.
- BN is treatable and many affected people have successfully recovered with mental health therapy and support groups.
