Skeletal muscle loss can persist in individuals with anorexia nervosa (AN) even *after* they’ve regained a healthy weight, challenging conventional recovery metrics.
Weight restoration is often seen as the finish line for anorexia nervosa recovery, but a growing body of research suggests it’s more like a pit stop. “In clinical studies, we usually define weight recovery as a body-mass index of 18.5 or within 95% of their age-predicted norm,” explains Megan Rosa-Caldwell, an assistant professor of exercise science at the University of Arkansas specializing in muscle biology. “Usually if someone is maintaining a weight above their underweight status, that is when there is not as much medical treatment.”1 But what if getting back to a “normal” weight doesn’t mean getting back to *normal*?
Defining Weight Recovery Versus Functional Recovery
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In clinical practice, weight recovery is commonly used as a benchmark for improvement in AN, but this metric may oversimplify the complexity of recovery. Emerging research indicates that while fat mass can return with adequate nutrition, a deficit in skeletal muscle mass can stubbornly persist.1,2 This matters because muscle isn’t just for show; it’s vital for mobility, strength, metabolism, immune function, and even how the body processes medications. A muscle deficit can leave individuals vulnerable to weakness, injury, and reduced overall resilience, regardless of their BMI.
Muscle Atrophy as a Consequence of Prolonged Malnutrition
Anorexia nervosa induces widespread breakdown of lean body mass due to chronic energy deficiency. Studies have shown that malnutrition causes a significant loss of both peripheral and axial skeletal muscle, stemming from reduced protein synthesis and increased protein breakdown.3 These changes affect not only the *amount* of muscle but also its *quality*, impacting muscle fiber composition and mitochondrial function—and these aspects may take longer to recover than weight alone.
Recent research and clinical data suggest that muscle regeneration pathways can remain impaired even with increased nutritional intake.1,2 This can explain lingering symptoms like muscle weakness, reduced exercise capacity, or functional impairment, even in patients who appear to be improving on standard recovery scales. According to Rosa-Caldwell, “musculoskeletal complications are probably lasting longer than people think and should probably be taken into consideration when we think of how to treat these individuals.”1
Where’s the Disconnect Between Refeeding and Muscle Restoration?
Nutritional restoration is essential for survival, but it may not be enough to rebuild muscle tissue. A study published in The Journal of Nutritional Physiology revealed that muscle protein synthesis doesn’t respond normally to adequate caloric intake, particularly after prolonged starvation.2 Other factors, such as endocrine disorders, inflammation, or neuromuscular junction disorders, can also hinder muscle tissue repair.
This disconnect highlights a potential flaw in current treatment models, which often reduce clinical care once weight goals are met. Patients may be discharged from intensive care before functional recovery is complete, and these long-term complications may go undetected or unaddressed. Rosa-Caldwell points to this gap, asking, “how can we implement interventions to get the muscle back faster?”1
How Can the Pharmacist Support Comprehensive Recovery?
Pharmacists are uniquely positioned to bridge the gap between weight recovery and functional recovery in AN. They can monitor medications that may affect muscle function, including corticosteroids or those regulating electrolytes. Pharmacists can also advise patients on optimal protein and amino acid intake for muscle restoration, as well as the potential need for vitamin D and zinc supplementation.
Furthermore, pharmacists can assess pharmacokinetic processes—how the body absorbs and distributes drugs—which can be altered by decreased lean body mass. A muscle mass deficit could affect how certain medications are processed, necessitating closer patient monitoring.
Rethinking Long-Term Management Strategies
Recognizing the disparity between weight recovery and true recovery may require more than just follow-up care. Incorporating resistance training, physical therapy, or tailored nutrition plans could be crucial for muscle recovery.1,2 Pharmacists, as accessible healthcare professionals, can help reinforce treatment plans and refer patients for ongoing care.
Ultimately, these findings challenge the idea that weight alone is a sufficient measure of recovery in AN. Persistent muscle damage may be an underrecognized contributor to relapse risk and long-term health problems. By broadening the definition of recovery to include functional and musculoskeletal health, clinicians—including pharmacists—can support more durable, holistic outcomes for patients.
REFERENCES
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Anorexia nervosa may result in long-term skeletal muscle impairment. EurekAlert! Published January 5, 2026. Accessed January 7, 2026. https://www.eurekalert.org/news-releases/1111559
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Rosa-Caldwell ME, Breithaupt L, Kaiser UB, Muhyudin R, Rutkove SB. Changes in muscle strength and moderators of protein turnover in a rodent model of anorexia nervosa and recovery. The Journal of Nutritional Physiology. 2025;4:100010. doi:https://doi.org/10.1016/j.jnphys.2025.100010
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Garrido EM, Lodovico LD, Dicembre M, et al. Evaluation of muscle-skeletal strength and Peak-Expiratory-Flow in severely malnourished inpatients with anorexia nervosa: a pilot study. Nutrition. Published online January 2021:111133. doi:https://doi.org/10.1016/j.nut.2020.111133
