When Eating Disorders and OCD Overlap: Understanding the Connection

Posted on: September 9th, 2026 by Sarah Lowenthal

A teenager cuts her sandwich into exactly eight pieces before she can eat it. Another patient checks the nutrition label on a food again and again, even though she already knows what it says. Someone else eats the same breakfast from the same bowl at precisely the same time every morning—and becomes intensely anxious if something disrupts the routine.

Are these eating disorder behaviors? OCD? Or both?

Sometimes, the answer is not immediately obvious.

Obsessive-compulsive disorder (OCD) and eating disorders are distinct illnesses, but they frequently overlap. They can share features such as intrusive or repetitive thoughts, rigid rules, perfectionism, avoidance, reassurance seeking, and ritualized behaviors. Research suggests that OCD occurs at substantially higher rates among people with eating disorders than in the general population. [1,2]

Understanding that overlap matters because the behavior we see on the outside doesn’t always tell us what is happening underneath.

When a Food Rule Starts to Feel Like a Compulsion

Eating disorders can create an extraordinary number of rules.

A person may feel that they must eat at a particular time, use a particular utensil, cut food in a certain way, check their body after eating, exercise according to an exact schedule, or repeatedly ask whether a meal was “too much.”

Breaking one of these rules can produce tremendous anxiety.

That can look remarkably similar to OCD. In OCD, an unwanted thought, sensation, image, or doubt creates distress, and a person feels driven to perform a behavior—or mental ritual—to reduce that distress. Unfortunately, the relief is usually temporary. The brain learns that performing the ritual made the anxiety go away, which makes the urge to perform it even stronger the next time.

Something similar can happen in an eating disorder.

Consider someone who is afraid that eating a particular food will cause weight gain. Avoiding the food decreases anxiety in the short term. The next time the food appears, however, it may feel even more frightening. Avoidance has unintentionally reinforced the fear.

The cycle can become:

Fear → anxiety → ritual or avoidance → temporary relief → stronger fear

This is one reason eating disorders can become so entrenched. Behaviors that initially make a person feel safer can gradually make their world smaller.

Researchers have identified several processes that may contribute to both OCD and eating disorders, including perfectionism, intolerance of uncertainty, repetitive negative thinking, anxiety and fear, difficulty tolerating distress, and compulsive or ritualistic behavior. [3] Obsessive thinking itself also appears to be particularly closely associated with eating disorder symptoms in anorexia nervosa and atypical anorexia nervosa. [4]

Similar on the Outside, Different on the Inside

One of the most important clinical questions is not simply “What is this person doing?”

It is “Why does this person feel compelled to do it?”

Imagine two people who refuse to eat a piece of pizza.

One thinks:

“If I eat that, I will gain weight.”

Another thinks:

“Someone may have touched it with contaminated hands, and I could become seriously ill.”

The behavior is identical: neither person eats the pizza.

But the reason for the behavior is very different.

The first may be experiencing eating-disorder-driven fear. The second may be experiencing contamination OCD. And a third person might experience both.

This distinction is particularly important in children and adolescents, because OCD can sometimes cause significant food restriction without a traditional fear of weight gain. A child may avoid food because of contamination fears, fear of vomiting, a need for things to feel “just right,” or an intrusive fear that something terrible will happen if a particular food is eaten.

Conversely, someone with an eating disorder may develop rituals around weighing, measuring, exercise, body checking, food preparation, or eating that look very much like OCD compulsions.

That is why careful assessment matters. Similar-looking behaviors can have very different functions and may require different treatment approaches.

“But I Know It Doesn’t Make Sense”

One particularly painful feature of both illnesses is the gap that can develop between what a person knows and what they feel able to do.

A patient may know intellectually that eating one dessert will not suddenly change their body.

They may know that missing one workout will not cause something terrible to happen.

They may know they have already checked the ingredient list five times.

And yet the anxiety remains.

This is not stubbornness or a failure to understand nutrition. Simply providing more information often isn’t enough, because the problem isn’t necessarily a lack of information.

The person is trying to obtain something the brain can never completely provide: certainty.

Can I be absolutely certain I won’t gain weight?

Can I know for sure that this food isn’t contaminated?

Can I be positive I ate exactly the right amount?

Can someone reassure me one more time?

Unfortunately, each attempt to obtain perfect certainty can strengthen the cycle.

Recovery often involves learning something very different: I can tolerate uncertainty, experience anxiety, and still move forward.

Why Starvation Can Complicate the Picture

There is another important layer to this relationship.

Malnutrition itself can increase preoccupation with food and contribute to cognitive and behavioral rigidity. This means that in someone with anorexia nervosa or another restrictive eating disorder, it may be difficult to determine how much obsessive-compulsive behavior reflects an underlying OCD diagnosis and how much has been intensified by starvation.

At the same time, anxiety and obsessive-compulsive symptoms cannot simply be attributed to malnutrition. Research has found that anxiety disorders frequently predate the onset of anorexia nervosa and bulimia nervosa, suggesting that an underlying vulnerability may be present before the eating disorder develops. [1]

For this reason, nutritional rehabilitation is not separate from psychiatric treatment. It is part of it.

A malnourished brain is being asked to do enormously difficult psychological work. Restoring adequate nutrition can improve cognitive and emotional functioning and can also help the treatment team better understand which symptoms remain when the effects of malnutrition begin to resolve.

What Does Treatment Look Like When Someone Has Both?

When OCD and an eating disorder occur together, treating only one may leave an important part of the illness untouched.

OCD is commonly treated with cognitive behavioral therapy incorporating exposure and response prevention (ERP). In ERP, a person gradually encounters something that creates anxiety while practicing not performing the ritual or avoidance behavior normally used to make the anxiety disappear.

There are interesting parallels in eating disorder treatment.

Someone afraid of particular foods may gradually incorporate those foods into meals. Someone who compulsively checks their body may work on reducing body checking. Someone who requires every meal to follow an exact routine may practice increasing flexibility. The goal is not to eliminate anxiety before taking action. It is to discover that anxiety can rise—and eventually fall—without obeying the eating disorder or OCD.

Exposure-based approaches have also been studied specifically in anorexia nervosa. In an early study, Steinglass and colleagues used exposure and response prevention to target fear of food, suggesting that learning to experience food-related anxiety without escaping or avoiding it may have a useful role in treatment. [5]

Clinical work integrating ERP principles with comprehensive eating-disorder treatment has also shown promising results for people experiencing both conditions, although the evidence base for treating co-occurring OCD and eating disorders remains much smaller than the evidence supporting treatment of either disorder individually. [6]

There is also an important caveat: ERP for OCD should not be used in a way that undermines nutritional rehabilitation.

For someone with a restrictive eating disorder, adequate nutrition, medical stability, and weight restoration when indicated remain essential. Treatment may need to integrate medical care, nutritional rehabilitation, psychotherapy, psychiatric treatment, and family support rather than treating the OCD and eating disorder as two unrelated problems.

The Goal Isn’t to Take Away Every Routine

Not every routine is pathological.

Most of us have preferred breakfasts, favorite foods, exercise routines, and ways we like things done.

The question is how much freedom remains.

Can you change the plan?

Can you eat something different?

Can you miss a workout?

Can you tolerate not knowing exactly what is in a restaurant meal?

Can you move on without checking one more time?

Can you participate in your life even when things don’t feel exactly right?

Healthy routines generally make life easier.

Compulsions make life narrower.

That distinction can be incredibly useful for patients and families trying to understand when seemingly “healthy” behaviors have crossed into something more concerning.

Looking Beyond the Behavior

One of the reasons I find the overlap between OCD and eating disorders so important is that it reminds us to remain curious.

Instead of asking only:

How do we get this person to stop doing this?

We can ask:

What fear is this behavior trying to manage?

What happens if the person doesn’t do it?

Is this about weight or shape—or contamination, harm, vomiting, symmetry, or something else?

Is the behavior providing temporary relief from anxiety?

How much flexibility and freedom has been lost?

Eating disorders and OCD are not the same illness, and researchers continue to investigate exactly how closely related they are. At the same time, their overlap is substantial enough that clinicians treating one should be attentive to the possibility of the other. [1-4]

Most importantly, identifying both doesn’t mean that someone has “one more thing wrong with them.”

It gives us more information.

And more information allows us to build treatment that addresses not just the behaviors we can see, but the fears, thoughts, and patterns underneath them.

Sometimes recovery begins not by asking someone to try harder to stop a behavior, but by understanding what that behavior has been helping them survive—and then helping them discover that they no longer have to obey it.

References

[1] Kaye WH, Bulik CM, Thornton L, Barbarich N, Masters K. Comorbidity of anxiety disorders with anorexia and bulimia nervosa. Am J Psychiatry. 2004;161(12):2215-2221.

[2] Mandelli L, Draghetti S, Albert U, De Ronchi D, Atti AR. Rates of comorbid obsessive-compulsive disorder in eating disorders: a meta-analysis of the literature. J Affect Disord. 2020;277:927-939.

[3] Williams BM, Brown ML, Sandoval-Araujo L, Russell S, Levinson CA. Psychiatric comorbidity among eating disorders and obsessive-compulsive disorder and underlying shared mechanisms and features: an updated review. J Cogn Psychother. 2022;36(3):226-246.

[4] Levinson CA, Brosof LC, Ram SS, Pruitt A, Russell S, Lenze EJ. Obsessions are strongly related to eating disorder symptoms in anorexia nervosa and atypical anorexia nervosa. Eat Behav. 2019;34:101298.

[5] Steinglass JE, Albano AM, Simpson HB, Carpenter K, Schebendach J, Attia E. Fear of food as a treatment target: exposure and response prevention for anorexia nervosa in an open series. Int J Eat Disord. 2012;45(4):615-621.

[6] Simpson HB, Wetterneck CT, Cahill SP, et al. Treatment of obsessive-compulsive disorder complicated by comorbid eating disorders. Cogn Behav Ther. 2013;42(1):64-76.