A Functional Medicine Lens on Eating Disorders and Ultra-Processed Food Use Disorders: A Narrative Review

David A. Wiss, PhD, RDN, IFMCP

David A. Wiss, PhD, RDN, IFMCP, Nutrition in Recovery LLC, Los Angeles, California, USA.

Corresponding author: David A. Wiss, PhD, RDN, IFMCP  

E-mail: davidawiss@nutritioninrecovery.com

Keywords: Adverse childhood experiences, Ultra-processed food addiction, Eating disorders, Trauma-informed care, Neurodiversity, Functional medicine

Introduction

Eating disorder (ED) and the non-official designation of ultra-processed food use disorder (UPFUD)—a clinical presentation applying substance use disorder (SUD) criteria to ultra-processed food consumption¹—have traditionally been examined as distinct entities. This conceptual separation has resulted in a theoretical impasse with clinical implications: patients exhibiting both restrictive and addictive eating features often receive conflicting guidance regarding food consumption and dietary restraint.²

Despite advances in psychological interventions, treatment outcomes for binge-type presentations have not improved over the past four decades.³ The functional medicine principle of identifying root causes suggests that upstream factors common to both presentations may be overlooked, although highly informative for understanding the etiology of eating behavior in mental health.

This narrative review introduces a unified life course model that integrates ED and UPFUD within a single framework, supported by original research demonstrating adverse childhood experiences (ACEs) as a shared developmental origin. The model provides functional medicine practitioners with a trauma-informed approach to assess and personalize treatment selection, which can be ideally implemented within a collaborative care team that includes mental health and nutrition professionals trained in disordered eating.

Main Narrative

A Unified Framework of Restrictive and Addictive Eating

The proposed model delineates two developmental pathways, Restrictive and Addictive Eating, both originating from generational trauma but diverging according to neurodevelopmental risk factors (Figure 1). This framework organizes eating pathology across six temporal stages: Historical (generational trauma), Predisposing (parental psychiatric history), Developmental (endophenotypes), Behavioral (eating patterns), Mental Health (clinical disorders), and Metabolic Health (physical sequelae).

Figure 1. A Unified Theory of Restrictive and Addictive Eating⁴

Abbreviations: OCD, Obsessive Compulsive Disorder; ED, Eating Disorder; DE, Disordered Eating; SUD, Substance Use Disorder; ADHD, Attention Deficit Hyperactivity Disorder; ACEs, Adverse Childhood Experiences; UPFUD, Ulta-Processed Use Disorder.

The Restrictive Eating Pathway progresses from generational trauma through parental symptoms of EDs and obsessive-compulsive disorder (OCD) traits. In this context, ACEs may become biologically embedded,⁵ manifesting as compulsivity, perfectionism, and cognitive rigidity. Individuals following this pathway often adopt dietary restriction as a primary coping mechanism to impose order in unpredictable environments. Behaviorally, this is expressed as “over-ordered” eating characterized by rigid food rules, culminating in anorexia nervosa and restrictive variants of other EDs.⁶

The Addictive Eating Pathway also originates from generational trauma but progresses through parental symptoms of SUDs and attention-deficit/hyperactivity disorder (ADHD) traits. In this pathway, ACEs are associated with deficits in reward processing, impulsivity, and delay discounting.⁷ Individuals are drawn to hedonic eating as a form of self-medication for negative affect. Behaviorally, this is characterized by “under-ordered” eating, marked by loss of control and progression to UPFUD, binge eating disorder, and frequently co-occurring SUDs.⁸

Importantly, the proposed model acknowledges that individuals may display features of both pathways and transition between them throughout the lifespan, especially during periods of stress or treatment. Notably, SUDs are conceptualized not as a central hub for all pathology, but as a frequent comorbidity and a potential crossover point between pathways.⁹

Original Research: ACEs as the Upstream Driver

Two studies from a private mental health nutrition practice provide empirical support for this framework (Table 1). In adults seeking nutrition counseling, post-traumatic stress disorder (PTSD) symptoms were found to fully mediate (99.4%) the ACE-ED relationship, while UPFUD mediated 73.8% of the association between ultra-processed food intake and ED symptoms.¹⁰ Critically, four or more ACEs predicted UPFUD-positive screens (OR=1.99, P = .01) but did not predict traditional ED-positive screens (OR=1.36, P = .25), with SUD history significantly moderating the ACE-UPFUD relationship.⁹ This differential prediction indicates that cumulative adversity predisposes toward the Addictive Eating Pathway, particularly when compounded by substance-related reward dysfunction—a phenotype that conventional ED instruments may overlook.

Table 1. Summary of Original Research Supporting the Unified Framework

Clinical Implication: Cumulative adversity predisposes toward the Addictive Eating Pathway, particularly when compounded by SUD history. Conventional ED screening instruments may overlook this phenotype because they emphasize shape and weight concerns rather than addictive-relevant features.

Abbreviations: SUD, Substance Use Disorder; PTSD, Post-Traumatic Stress Disorder; ACE, Adverse Childhood Experiences; ED, Eating Disorder; UPFUD, Ultra-Processed Food Use Disorder; UPF, Ultra-Processed Food.

 Functional Medicine Alignment

The Unified Framework aligns with core principles of functional medicine. It posits that eating pathology arises from interconnected antecedents (generational trauma, parental mental health), triggers (hedonic eating, dietary restriction), and mediators (PTSD, SUDs, UPFUD) rather than isolated diagnostic categories.¹⁰ The biological embedding of ACEs—including hypothalamic-pituitary-adrenal (HPA) axis dysregulation, alterations in reward circuits, epigenetic modifications, and disruption of the gut microbiome—provides mechanistic pathways that are amenable to lifestyle-based interventions.^12,13

 Lifestyle Strategies for Pathway-Specific Care

The two-pathway model informs personalized lifestyle prescriptions. Restrictive-pathway presentations, characterized by serotonergic dysfunction shared with OCD-spectrum traits,¹⁴ may benefit from dietary liberalization, graduated exposure to feared foods, and interventions supporting serotonin function. Sleep optimization is particularly relevant, as circadian disruption and night eating often accompany restricted-binge patterns.¹⁵ Adequate sleep supports serotonin synthesis and reduces the cognitive rigidity characteristic of this pathway.

Addictive-pathway presentations reflect dopaminergic dysfunction—a hypodopaminergic state with blunted reward sensitivity.¹⁶ Lifestyle interventions should aim to restore the dopamine system. Regular physical activity offers particular benefit: aerobic exercise increases dopamine receptor availability and improves reward processing, providing a non-pharmacological approach to addressing the reward deficits underlying addiction-like eating.¹⁷ Movement also supports mood regulation and stress resilience, addressing upstream drivers of hedonic eating.

Social support represents a critical modifiable factor across both pathways. Perceived social support has been shown to moderate the relationship between ACEs and maladaptive addictive behaviors, serving as a potential protective factor against the biological embedding of adversity.¹⁸ Group-based treatment approaches that emphasize community connection alongside nutritional change have demonstrated sustained improvements in UPFUD symptoms at 12-month follow-up.¹⁹

The therapeutic partnership itself constitutes a healing intervention. For individuals whose developmental adversity included relational trauma, the experience of a consistent, non-judgmental collaborative relationship with practitioners may help restore capacity for healthy attachment and self-regulation. Functional medicine, emphasizing patient-centered care, positions practitioners to provide this corrective relational experience.

Patients in the “gray area” require hybrid approaches. Assessment of OCD-spectrum traits (compulsivity, rigidity) versus ADHD-spectrum traits (impulsivity, reward sensitivity) guides the relative emphasis on serotonergic versus dopaminergic lifestyle strategies, with trauma-informed care remaining foundational for both.

 Conclusion

ACE screening should be routine in the assessment of eating pathology. The finding that four or more ACEs predicted UPFUD, but not traditional ED screens, highlights limitations of conventional approaches, which may overlook addiction-relevant presentations in individuals with SUD history.

The two-pathway model offers a clinical decision framework. Assessment of OCD-spectrum traits (compulsivity, rigidity, perfectionism) versus ADHD-spectrum traits (impulsivity, reward sensitivity, delay discounting) can guide treatment selection beyond categorical diagnosis, utilizing a neurodiversity framework.

Trauma-informed care is foundational rather than adjunctive. The near-complete mediation of the ACE-ED relationship by PTSD symptoms indicates that addressing trauma may be essential for sustained improvement in eating-related outcomes.

UPFUD should be recognized as a distinct clinical entity. Its role as a mediator between ultra-processed food intake and broader ED symptomatology, as well as between PTSD and EDs, positions addiction-like eating as a mechanism rather than solely a comorbidity.

Functional medicine practitioners are well-positioned to implement this framework through root-cause assessment, personalized lifestyle interventions, and therapeutic partnerships. Collaboration with mental health and nutrition professionals trained in trauma-focused, addiction-informed care optimizes outcomes for this complex patient population.

 Funding

No funding was received for this work.

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