Knowing the why behind something can be empowering; though this is true everywhere, it can be particularly resonant within the mental health space. A specific diagnosis can help providers create a treatment plan that addresses both the symptoms and the underlying cause of a condition. That’s why recent research on the influence of genetics on Avoidant/Restrictive Food Intake Disorder (ARFID) has provided a (much needed) revelation about a disorder that we really don’t know that much about. Eating disorders, in general, have historically been misunderstood and stigmatized. 

In this article, we’ll explore what this new research tells us about ARFID and why understanding the genetic roots of eating disorders is so important. But first, let’s take a step back and examine why eating disorders are so difficult to study and why research like this leads to better treatment and intervention.

Why Is It Difficult to Study Eating Disorders?

There are a few reasons for the lagging research on ARFID. First of all, there’s the stigma surrounding the “realness” of many mental illnesses (that’s a topic for another time). But there’s also a disconnect in the science world between mental and physical health. Traditionally, they’ve been treated as separate. But the more we understand about how our bodies and minds interact, we see the value in prioritizing mental health care. Still, EDs continue to be misunderstood and under-diagnosed. Here’s a bit of the context for this challenge:

1. Complex Interactions Between Genetics and Environment: We know both genetics and external factors shape the risk of developing an eating disorder, but how much?
2. Bias in Research: Studies on EDs have historically focused on young, white women with a disproportionate lens on anorexia nervosa and bulimia nervosa. This has left folks of other genders, racial identities, ages, and those with other types of eating disorders on the sidelines.
3. Variation in Presentation: Eating disorders do not always look the way people expect. Not everyone with an eating disorder is underweight, and not all eating behaviors are tied to body image concerns. ARFID, for example, often gets dismissed as “picky eating” in childhood, delaying proper diagnosis and treatment.
4. Challenges in Diagnosis: The DSM-5 diagnostic criteria help clinicians identify eating disorders, but diagnoses are evolving as research improves. ARFID, in particular, was only included as an eating disorder in the DSM-5 in 2013. The diagnostic criteria were adapted from the “feeding disorder of infancy or early childhood,” which had restrictive age requirements. Because of this, much research on restrictive eating before this time did not account for ARFID as a separate disorder. This has led to limited data on its prevalence, causes, and long-term outcomes.

What Is ARFID? 

Let’s start with some background: What do we know about ARFID? We’ll start with the basics. Avoidant/Restrictive Food Intake Disorder is an eating disorder characterized by an extreme avoidance of certain foods, a lack of interest in eating, or an intense fear of negative consequences associated with eating. Health consequences of ARFID can be similar to other restrictive eating disorders like anorexia nervosa, but there’s a key difference in motivation. With an ARFID diagnosis, body image concerns or a fear of weight gain aren’t the driving factors of the disordered eating behaviors.

ARFID can develop at any age but it typically presents in childhood and adolescence. Because of the restrictive nature of the ED, those suffering may experience significant weight loss, failure to gain weight, and nutritional deficiencies. The disorder can have serious implications for physical and mental health, often leading to social and emotional distress. 

Presentations of ARFID

There are three subtypes that can add clarity to an ARFID diagnosis. While they aren’t mutually exclusive, categorizing ARFID into a subtype can help researchers, clinicians, and caregivers better understand the disorder and guide treatment. The three types are described as limited intake, limited variety, and aversive. 

Limited Intake

Some individuals with ARFID have little to no interest in eating. They may report low appetite, feel indifferent toward food, or engage in behaviors that reduce food intake, such as taking small bites, excessive chewing, or eating extremely slowly. This presentation often leads to a lower body weight and a greater risk of malnutrition. Some individuals in this category may also be at increased risk for developing restrictive eating disorders, such as Anorexia Nervosa, later in life.

Limited Variety

Often mistaken for “picky eaters,” this form of ARFID is characterized by extreme selectivity based on sensory properties such as texture, taste, or smell. This presentation is commonly seen in early childhood but can persist into adulthood. Individuals with this presentation may not necessarily be underweight, but they can be at risk for nutrient deficiencies. Those struggling may feel fearful of trying new food or unfamiliar sensory characteristics. 

Aversive

This presentation of ARFID stems from a fear of adverse physical consequences from eating. Individuals may avoid food due to a past traumatic experience, such as choking, vomiting, or an allergic reaction. The fear of experiencing discomfort or danger from eating can be so overwhelming that it leads to food avoidance and malnutrition. This subtype is often associated with anxiety disorders and can be triggered by a single distressing event.

While these subtypes provide a helpful framework for understanding ARFID, they are not rigid categories. Many individuals experience a combination of these presentations, and symptoms can evolve over time. 

Comorbidities of ARFID

There appears to be a relationship between ARFID and other mental health conditions. About 50% of the time, an ARFID diagnosis shows up alongside other psychiatric and neurodevelopmental disorders.

A few of the most common comorbid diagnoses include anxiety, autism spectrum disorder (ASD), and attention-deficit/hyperactivity disorder (ADHD). Over 70% of those with ARFID also have an anxiety diagnosis, making it the most common comorbid condition. 

Potentially rooted in sensory sensitivities, there also seems to be an overlap between ARFID and autism. A study on the relationship between the two found that up to 54% of autistic individuals may also meet the criteria for ARFID. 

ADHD is another neurodevelopmental disorder that we often see co-occurring with ARFID. Some individuals with ADHD may struggle with impulsivity around food choices, while others may experience reduced appetite due to stimulant medications. The difficulty in maintaining structured eating patterns may also contribute to ARFID symptoms.

It’s important to recognize these comorbidities as they can impact treatment and recovery. 

Closing the Gap

Because ARFID is a relatively new eating disorder diagnosis, much of what we understand about it is still evolving. While diagnostic criteria and common comorbidities can help identify ARFID, researchers and clinicians acknowledge that our understanding of the disorder is far from complete. As more studies emerge, it is likely that the criteria for ARFID will continue to shift, providing a more nuanced and accurate picture of the disorder.

Research on ARFID and Genetics

The causes of eating disorders have been fuzzy, but only because they are so nuanced. While we know that a mix of risk factors contribute to the likelihood that someone develops an ED, the extent has historically been less clear. However, genetic studies have made this more possible. We’ve learned that EDs like anorexia nervosa, bulimia nervosa, and binge eating disorder are tied to a complex polygenetic landscape. 

That essentially means that several (potentially around eight) genes interact to create the biological likelihood of developing an eating disorder. But notice how we didn’t mention ARFID? That hearkens back to the representation bias we mentioned earlier. 

However, the research on other EDs does give scientists a starting point for asking the same questions about ARFID. Plus, this knowledge helps us continue to discredit the misinformation that EDs are a choice.

Before we dissect the ARFID-specific research, here’s some more background on what the researchers knew about eating disorders, feeding habits, ARFID, and heritability going into the more recent study. 

The Foundations: What We Already Know about Eating Disorders and Genetics

So, along with the interplay of multiple genes, what else do we know about the heritability of eating disorders?

Research into the heritability of eating disorders has long suggested that these illnesses run in families. Twin studies, which compare identical twins (who share 100% of their genes) with fraternal twins (who share about 50% of their genes), help scientists estimate the genetic contribution to various disorders.

A review of these epigenetic studies estimates the heritability of anorexia nervosa to be between 48-74%, bulimia nervosa between 55-61%, and binge eating disorder between 39-57%.

In addition to studies on other eating disorders, research on feeding behaviors has shown that patterns in appetite, food preference, and nutrient intake are genetically linked. Another twin study (get used to these) found that both micronutrient absorption and taste perception are heritable. Given that ARFID often involves extreme selectivity around food textures, tastes, and smells, these findings suggest that some of the restrictive behaviors seen in ARFID may have a biological basis.

The last piece of context is ARFID-specific. A 2021 study examined the relationship between genetics and ARFID in a cohort of autistic patients. They discovered a genetic link between intellectual disability and gastrointestinal issues, which increase the risk factor for ARFID. 

While these findings helped establish the relationship between ARFID and ASD, they did not provide a full picture of ARFID’s genetic basis—after all, not everyone with ARFID has ASD, and not everyone with ASD develops ARFID. This gap in research led scientists to pursue broader genetic studies to determine just how much of ARFID is inherited.

New Research Implications

While previous studies hinted at a genetic link in ARFID, no large-scale research had directly measured how much of the disorder could be attributed to genetic inheritance. A 2023 study from JAMA Psychiatry gives us the context to better understand the causes behind this often-misunderstood condition.

The Study Design: A Large-Scale Analysis of ARFID Heritability

When conducting a large-scale genetic study, you need a big sample size. To achieve this, researchers used data from the Child and Adolescent Twin Study in Sweden (CATSS)—one of the largest twin studies in the world. This database included information on 16,951 pairs of twins born between 1992 and 2010. 

By linking this data to Sweden’s National Patient Register (NPR) and the Prescribed Drug Register (PDR), researchers were able to track medical and psychiatric histories, which they used to identify individuals that met the criteria for ARFID. This approach helped them identify 682 children (2.0%) with characteristics consistent with ARFID, creating the largest sample size ever used to examine ARFID’s genetic basis.

What the Study Found: ARFID May Be the Most Heritable Eating Disorder

The study found that ARFID is highly heritable. With a rate of 79%, ARFID is more heritable than rates reported for other eating disorders. This means that nearly 80% of the likelihood of developing ARFID can be attributed to genetic factors rather than environmental factors. 

This is a major step toward better understanding this condition. As ARFID has been historically misunderstood, underdiagnosed, and often dismissed as extreme picky eating, the findings from the recent twin study reinforce that ARFID is not simply a behavioral choice or a result of personal preference—it has a strong biological foundation.

Now What? Assessment and Treatment for ARFID

So what does this research mean for those living with an ARFID diagnosis? What does it mean for you as a loved one or caregiver to someone suffering? While the research concludes that this study supports “future twin and molecular genetic studies,” the promise of more research may feel vague for those experiencing the real-life implications of this disorder. 

So, let’s put it into context. This research doesn’t constitute any major changes to how we assess or treat ARFID. It does confirm that family health history is an important piece of information when identifying folks who may be at risk for developing an ED. As far as treatment, we can look to other research to see what treatment types seem to be the most impactful. 

Potential Treatment Options

A 2024 review gives us a recent analysis of which treatments are most effective for ARFID. The studies included in the review referenced a range of settings from outpatient to virtual to inpatient treatment programs. 

Types of therapeutic modalities that this review highlighted include:

• Behavioral interventions (like positive reinforcement or tying eating to a preferred activity)
• Cognitive behavioral therapy (CBT)
• Mindfulness exercises like positive self-talk and breathing exercises to reduce anxiety
• Family-based interventions

These treatments had a range of positive impacts. Many saw improvements in physical health, like increased weight and improved blood test results, along with improved mental and emotional health. After receiving treatment, patients reported a better eating experience, decreased fears, and social improvements. 

You’re Not Alone with The Alliance

By broadening our understanding of eating disorders, this research challenges outdated narratives about what causes them. Recognizing that genetics play a role in ARFID reinforces the reality that these conditions are not a choice, and they deserve the same level of medical attention and compassion as any other illness. 

Figuring out how to navigate an ARFID diagnosis can be intimidating, but it doesn’t have to be isolating. Here at The Alliance, we support a community of folks impacted by eating disorders, including those struggling and their loved ones. Our helpline is staffed by licensed mental health professionals; call anytime between 9:00 am to 7:00 pm EST to connect with the care you need. We also offer virtual support groups for both those suffering and their loved ones. Recovery is possible and The Alliance is here to support you every step of the way.