Eating disorders cause damage that extends far beyond the period of active illness. Even after recovery, many people live with lasting effects on their heart, bones, brain, digestive system, teeth, and hormones. Anorexia nervosa carries the highest physical toll, with a mortality rate 2.7 times higher than bulimia nervosa, but every type of eating disorder leaves a distinct footprint on the body. Here’s what the research shows about each system affected.
Heart Damage and Cardiac Risk
The heart is one of the organs most vulnerable to eating disorders, and some of the damage is irreversible. In anorexia nervosa, chronic starvation causes the heart muscle itself to deteriorate. Cardiac MRI and post-mortem studies have found myocardial fibrosis, a type of scarring in the heart tissue that can lead to stiff, poorly functioning heart walls. Mitral valve prolapse is the most common valve abnormality in anorexia, and some studies show it persists even after weight is fully restored.
The heart’s electrical system also suffers. Critically underweight individuals are at increased risk of sudden cardiac death, most often from dangerous pauses in the heart’s rhythm rather than rapid heartbeats. As the duration of anorexia increases, the nervous system’s control over heart rate appears to shift in ways that may compound this risk.
For bulimia nervosa, the biggest cardiac threat comes from purging. Repeated vomiting disrupts electrolyte levels, particularly potassium, which is essential for maintaining a normal heartbeat. Cardiac arrhythmias are the highest-risk cardiovascular complication of purging. People who have used ipecac to induce vomiting face additional danger, as the substance is directly toxic to heart muscle and can cause cardiomyopathy.
Bone Loss That Doesn’t Fully Reverse
Eating disorders, especially anorexia, cause significant bone loss, and the damage is only partially recoverable. Among adults with anorexia, 92% have reduced bone density (osteopenia) and 38% have osteoporosis at one or more skeletal sites. The numbers are striking in younger patients too: up to 50% of adolescent girls with anorexia show measurably low bone density, and the figure reaches 70% in boys.
Weight gain and the return of menstrual periods do help. Bone density at the spine increases by roughly 3% per year and at the hip by about 2% per year during recovery. Without recovery, bone density drops by about 2.5% annually at both sites. But even with full weight restoration and resumed periods, bone density never catches up to that of people who were never affected. Residual deficits persist. This means a higher lifetime risk of fractures, particularly at the hip and spine, that follows someone well into middle age and beyond.
Changes in Brain Structure
Chronic malnutrition physically shrinks the brain. Studies using brain imaging have found lower gray matter volumes in the frontal lobes and the insula, a region involved in emotional awareness and body perception, in people with anorexia. The frontal lobes are responsible for executive functions like planning, decision-making, working memory, and impulse control. Reductions in these areas correspond to the cognitive rigidity, perfectionism, and difficulty with flexible thinking that characterize the illness.
These structural changes may also underlie problems with reward processing, social cognition, and emotional regulation that many people with eating disorders experience. While some brain volume recovers with nutritional rehabilitation, the degree of full restoration and the timeline remain uncertain, particularly for people who were ill during adolescence when the brain is still developing.
Digestive Problems That Linger
The gastrointestinal system takes a beating from both restriction and purging, and not all of the damage resolves with treatment. In anorexia, delayed gastric emptying is common, causing bloating, nausea, and early fullness that can make the refeeding process physically miserable. The good news is that gastric emptying tends to improve with weight gain, even before a person reaches a normal weight. The bad news is that other problems are more stubborn.
About 40% of people with anorexia show pelvic floor dysfunction, which contributes to severe constipation. In one study, a four-week refeeding program normalized the speed of movement through the colon but did not fix the pelvic floor problems, suggesting structural damage to the muscles involved. Chronic constipation in anorexia is also linked to changes in gut bacteria that increase intestinal methane production, which slows transit further.
For bulimia, long-term laxative abuse can cause melanosis coli, a darkening of the colon lining that typically resolves after stopping laxatives, and in rare cases “cathartic colon,” where the bowel loses normal ability to contract on its own due to prolonged stimulant laxative use.
Hormonal Disruption
Eating disorders throw the body’s hormonal systems into disarray, and some of these changes are slow to normalize. In anorexia, the thyroid essentially dials itself down as an energy-conservation strategy. Levels of the active thyroid hormone (T3) drop significantly, which lowers metabolic rate, body temperature, and energy levels. These changes typically reverse with weight restoration.
Cortisol, the body’s primary stress hormone, tells a different story. Up to 80% of women with anorexia have chronically elevated cortisol levels. The system that regulates cortisol becomes stuck in an overactivated state. Troublingly, this dysregulation can persist even after weight gain, suggesting the hormonal system doesn’t simply snap back to normal with recovery. Prolonged high cortisol is itself a contributor to bone loss, creating a compounding effect on skeletal health.
Lasting Damage to Teeth
Tooth erosion from bulimia is one of the most visible and permanent consequences of an eating disorder. Stomach acid from repeated vomiting dissolves tooth enamel, and once enamel is gone, it does not regenerate. The erosion progresses through stages: superficial enamel loss, penetration into the softer layer beneath (dentin) affecting less than a third of the tooth surface, and finally deep erosion covering more than a third. Half of the people with bulimia examined in one study hadn’t noticed their own tooth erosion until the damage was already advanced. In three out of five newly detected cases, the erosion had already reached the second stage.
The loss of tooth structure remains even after the eating disorder is fully treated. Severe cases require crowns or other restorative dental work, which is expensive and requires lifelong maintenance. The cosmetic changes, including shortened, translucent, or chipped front teeth, are conspicuous and persist indefinitely.
Fertility and Pregnancy
A history of an eating disorder has measurable effects on reproductive outcomes. Women previously diagnosed with anorexia have their first child about two years later on average than women in the general population (age 26.4 versus 24.1 in one large study). More significantly, they have far fewer children overall. Compared to their closest-aged sisters without eating disorders, women with a history of anorexia had roughly half the number of children.
Bulimia appears to have a smaller effect on fertility. Women with a history of bulimia did not differ significantly from their sisters in the number of children they had. But anorexia and other eating disorders were both associated with delayed first births and lower total number of pregnancies, even after adjusting for other factors. Eating disorders are also associated with higher risk of miscarriage and a greater likelihood of remaining childless.
Metabolic Effects of Binge Eating Disorder
Binge eating disorder (BED) carries its own set of long-term consequences, driven largely by the metabolic effects of repeated episodes of consuming large quantities of food. BED is significantly associated with components of metabolic syndrome: high blood pressure, elevated blood sugar, abnormal cholesterol levels, and excess abdominal fat. People with both obesity and BED tend to have higher cholesterol, a larger waist-to-hip ratio, and higher rates of fatty liver disease than people with obesity alone.
The chronic low-grade inflammation associated with BED and obesity drives increased risk of type 2 diabetes and cardiovascular disease over time. These are not simply consequences of weight. The pattern of binge eating itself, with its repeated surges in blood sugar and insulin, contributes independently to metabolic dysfunction.
Mortality
Eating disorders are among the deadliest psychiatric conditions. A meta-analysis of 36 studies published in JAMA Psychiatry found that people with anorexia nervosa die at roughly twice the expected rate for their age and sex (a standardized mortality ratio of 1.92). Anorexia’s mortality rate is 2.7 times higher than bulimia’s. Deaths result from the direct medical complications described above, particularly cardiac events, as well as from suicide, which accounts for a significant portion of eating disorder deaths. The risk increases with longer duration of illness, reinforcing that early and sustained treatment changes the trajectory of these conditions in concrete, life-or-death terms.