The Physical Side Effects of Anorexia (Short-Term & Long-Term)

Anorexia nervosa (AN) is an eating disorder characterized by an intense fear of gaining weight, severe food and caloric restriction, and a distorted body image.1

Reviewed By | Michelle Ervin, MEd

11 sources cited

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These symptoms frequently lead to a host of physical complications, which can affect nearly every internal system in the body and even be life-threatening without appropriate care.

General Side Effects of Anorexia

Even though anorexia nervosa is a mental illness, it can have several physical, emotional, and behavioral symptoms. These can include or lead to potentially life-threatening complications

The main physical side effects of anorexia are related to malnutrition, which often happens when someone works to prevent weight gain and/or actively lose weight by not ingesting enough calories. These can include:2,3,8

  • Anemia
  • Bone loss
  • Muscle loss
  • Cardiovascular problems
  • Weakened immune system
  • Brain and nerve problems
  • Bowel, gastrointestinal, or kidney problems
  • Endocrine system issues
  • Loss of periods in women
  • Decreased testosterone in men
  • Dermatological changes
  • Electrolyte abnormalities

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What Are the First Side Effects That Occur?

Anorexia nervosa and other eating disorders that involve severely restricted food intake lead to a number of problems that occur relatively quickly.

Among the first AN side effects to be seen is rapid or significant weight loss. This is due to the lack of calories and often excess exercise that commonly manifests as part of the condition. However, the lack of proper nutrition related to the severely restricted diet soon brings other issues.

Dehydration is an early sign of malnutrition. Low blood sugar (hypoglycemia) also occurs early, which can lead to mood changes, headaches, difficulties thinking straight, and poor balance.11 When body weight decreases drastically, it can take longer for the stomach to empty, leading to potential bloating, stomach pain, and constipation.11

Eventually, the body will attempt to adjust to a severely limited food intake by conserving more energy and slowing down normal processes. As blood flow slows down, intolerance to cold develops, and the fingers and ears can develop a bluish tint.11 The body may also produce fine hairs, called lanugo, on the arms, chin, lips, and spine, while hair loss is also possible.11

Sex hormones are impacted, which can cause menstruation to stop in women and low levels of testosterone in men. Sex drive is often affected.11

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What Are the More Serious Side Effects of Anorexia?

Among the most common eating disorders, anorexia nervosa is generally considered the most dangerous and deadly.9 In fact, AN is generally considered the deadliest mental health disorder behind only opioid addiction.5

Around a third of all deaths associated with anorexia are related to issues with cardiovascular health.6 Electrolyte imbalances and prolonged hypoglycemia caused by malnutrition can lead to serious heart irregularities, congestive heart failure, and other cardiovascular complications.

Other serious side effects include damage to different organ systems, anemia, hypoglycemia, low white blood cell count, seizures, and low bone mineral density.4Sadly, a high number of AN-related deaths are also caused by suicide. The issue is the second-leading cause of death for people with anorexia nervosa, likely due to the serious mental health complications that serve as the foundation of the condition.10

How Long Do Side Effects Last Once in Recovery?

Thankfully, it is possible to make a full recovery from anorexia nervosa. But just as the body adjusts in response to limited food intake, it will need time to adjust to a healthier relationship with food and movement.

How long this adjustment period lasts depends on several factors, including how severe the case was and how long the person struggled with disordered eating and issues related to malnutrition. These are just a few reasons why early intervention and treatment are crucial.7

Still, as time goes on, most of the physical side effects of AN will subside or even reverse as the body is replenished with appropriate vitamins and nutrients. Full physical recovery can take anywhere from several weeks to several months, though usually, the process is prolonged and doesn’t occur in a straight line of progress.

Potential Consequences of Not Getting Treatment for Anorexia

Eating disorders do not go away on their own. And while most physical complications of AN can be treated, some can become permanent if never appropriately addressed. Of course, the ultimate concern of not treating anorexia nervosa is the high mortality rate of the condition.

For this reason, it is essential to seek professional treatment as early as possible. A comprehensive treatment program with a multidisciplinary team of professionals well-versed in eating disorders is crucial to an effective recovery. 

Ultimately, the sooner you get help, the better your long-term outcomes.


  1. Anorexia Nervosa. (March, 2022). U.S. Department of Health and Human Services (HHS).
  2. Sidiropoulos M. (2007). Anorexia nervosa: The physiological consequences of starvation and the need for primary prevention efforts. McGill Journal of Medicine: MJM: an international forum for the advancement of medical sciences by students; 10(1):20–25. 
  3. Eating disorders. (n.d.). Substance Abuse and Mental Health Services Administration. Accessed February 2024.
  4. Gibson D, Watters A, Cost J, et al. (2020). Extreme anorexia nervosa: medical findings, outcomes, and inferences from a retrospective cohort. Journal of Eating Disorders; 8(25). 
  5. What are Eating Disorders? (n.d.). American Psychiatric Association. Accessed February 2024.
  6. Sardar MR, Greway A, DeAngelis M, Tysko EO, Lehmann S, Wohlstetter M, & Patel R. (2015). Cardiovascular Impact of Eating Disorders in Adults: A Single Center Experience and Literature Review. Heart views: the official journal of the Gulf Heart Association; 16(3):88–92. 
  7. Allen KL, Mountford VA, Elwyn R, Flynn M, Fursland A, Obeid N, Partida G, Richards K, Schmidt U, Serpell L, Silverstein S, & Wade T. (2023). A framework for conceptualising early intervention for eating disorders. European Eating Disorders Review; 31(2):320-334. 
  8. Anorexia nervosa. (n.d.). National Eating Disorders Association. Accessed February 2024.
  9. van Hoeken, D., & Hoek, H. W. (2020). Review of the burden of eating disorders: mortality, disability, costs, quality of life, and family burden. Current opinion in psychiatry; 33(6):521–527.
  10. Eating Disorders. (n.d.). National Institute of Mental Health. Accessed February 2024.
  11. Physical Effects of Anorexia. (2018, April 28). The Emily Project. Accessed February 2024.

Last Update | 03 - 27 - 2024

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