Anorexia nervosa carries one of the highest mortality rates of any psychiatric illness, with a standardized mortality ratio of 5.31, meaning people with anorexia are more than five times as likely to die prematurely compared to the general population. Even after recovery, the disorder can leave lasting damage across nearly every organ system. The effects depend on how long the illness lasted, how severe the malnutrition became, and whether purging behaviors like vomiting or laxative use were involved.
Bone Loss and Fracture Risk
Malnutrition disrupts the hormones that build and maintain bone, particularly estrogen in women and testosterone in men. The result is bone that’s thinner, weaker, and more prone to breaking. Adolescent girls with anorexia have bone density scores roughly one full standard deviation below their healthy peers at the hip, spine, and femoral neck. That gap matters: the lifetime fracture rate in people with anorexia is about 31%, compared to 19% in controls, a nearly 60% increase in relative risk.
What makes this especially concerning is that fractures occur even when bone density scans look relatively normal. In one large study, girls with anorexia whose bone density was only modestly reduced still had nearly double the odds of a prior fracture compared to healthy controls with similar scan results. This suggests the disorder changes bone quality, not just bone quantity. The peak years for building bone density are the teens and early twenties, so anorexia during this window can create a deficit that’s difficult or impossible to fully recover from, raising the risk of osteoporosis decades later.
Heart Damage
The heart is a muscle, and prolonged starvation causes it to shrink. Reduced left ventricular mass, mitral valve prolapse (in 33% to 60% of cases), and fluid around the heart (pericardial effusion, seen in 22% to 35%) are all common structural findings. About 25% of people with anorexia show signs of scarring in the heart muscle itself. Bradycardia, an abnormally slow heart rate, and low blood pressure are nearly universal during active illness.
Electrolyte imbalances from purging or laxative abuse add another layer of danger. Depleted potassium and magnesium can cause a prolonged QT interval, a change in the heart’s electrical rhythm that increases the risk of sudden cardiac arrest. During refeeding, when nutrition is reintroduced after prolonged starvation, the heart can be overwhelmed, sometimes triggering congestive heart failure. These cardiovascular complications are a leading cause of death in anorexia.
Brain Volume and Cognitive Effects
Active anorexia physically shrinks the brain. A meta-analysis of over 1,100 patients found that people with acute anorexia have roughly 4.8% less gray matter and 2.5% less white matter than healthy individuals. The reductions are even larger in adolescents. Key regions affected include the cingulate gyrus (involved in emotion regulation and decision-making), the precentral gyrus (motor control), and the precuneus (self-awareness and memory).
The encouraging part is that brain volume does improve with weight restoration. The discouraging part is that it takes a long time. Even after 1.5 years of sustained recovery, gray matter volume remains measurably lower than in people who never had the disorder. Cognitive effects during illness often include difficulty concentrating, rigid thinking, and impaired emotional processing. Whether these fully resolve with long-term recovery is still an open question, but the structural data suggests the brain needs years, not months, to rebuild.
Kidney Disease
Chronic dehydration, repeated vomiting, and persistent low potassium levels create a toxic environment for the kidneys. Over time, these factors cause inflammation and scarring in the kidney’s filtering structures, a process that can become irreversible. About 5.2% of people with anorexia eventually develop end-stage kidney disease requiring dialysis or transplant.
In a case series of 14 patients with anorexia-related kidney disease, 9 reached a serious kidney outcome: 6 experienced a doubling of their creatinine level (a marker of major kidney function decline), and 7 progressed to kidney failure. Biopsies in these patients showed collapsed filtering units, tissue scarring, and damage consistent with chronic low blood flow to the kidneys. The repeated cycle of dehydration, potassium depletion from purging, and poor nutrition gradually destroys tissue that the kidneys cannot regenerate.
Digestive System Changes
Delayed stomach emptying, or gastroparesis, is one of the most common gastrointestinal complaints during anorexia. It causes bloating, nausea, and feeling uncomfortably full after eating very little, which can make recovery meals feel physically unbearable. The good news is that this tends to improve relatively quickly once regular eating resumes. Research shows gastric emptying normalizes as feeding continues, though long-term rehabilitation works better than short-term refeeding for resolving symptoms fully.
Colon function follows a similar pattern. Constipation is nearly universal during active illness, but colonic transit time typically returns to normal within about three weeks of eating a balanced diet. One exception is pelvic floor dysfunction, which can persist even after nutrition is restored. For most people, the digestive system is one of the more resilient organs in recovery, though the discomfort during the refeeding process is a real barrier that makes early treatment feel worse before it feels better.
Fertility and Pregnancy Complications
Anorexia disrupts menstruation by suppressing the hormones that drive the reproductive cycle. The loss of periods, once considered a defining feature of the disorder, reflects a body that has shut down reproduction to conserve energy. The reassuring finding from long-term studies is that fertility often returns after recovery. In one study, all 14 women who wanted to conceive after recovering from anorexia did so within a year. Multiple studies have found that infertility rates in recovered patients are similar to the general population.
Pregnancy outcomes, however, tell a more complicated story. Women with a history of anorexia have significantly more miscarriages and higher rates of cesarean delivery compared to controls. One large study found that perinatal mortality (death of the baby around the time of birth) was six times higher than in the general population, and low birth weight was more than twice as likely. Low birth weight itself carries consequences for the child, including increased risk of metabolic disorders later in life. These risks appear to persist even when the mother has weight-restored before becoming pregnant.
Dental Erosion
About 27% of people with anorexia experience tooth erosion, a figure that rises substantially when purging is involved. In patients who vomit regularly, severe erosion on the tongue-side surfaces of the teeth, called perimolysis, is nearly always present. Stomach acid dissolves enamel, and anorexia also reduces saliva production, stripping away the mouth’s natural defense against acid and bacteria.
The combination of acid exposure and dry mouth creates a perfect environment for cavities. Patients who vomit daily tend to have both erosion and active decay. Unlike many other effects of anorexia, dental damage is completely irreversible. Enamel does not regenerate, and eroded teeth require lifelong dental management including crowns, bonding, or eventual extractions. Short-duration anorexia without purging may spare the teeth entirely, but years of purging behavior can cause damage visible even in relatively young patients.
Recovery Is Possible but Slow
A 22-year follow-up study found that nearly 63% of people with anorexia eventually achieve full recovery. That number is worth sitting with, because at the 9-year mark, only 31% had recovered. Recovery from anorexia often takes far longer than people expect, but the trajectory is one of continued improvement over many years, not a plateau.
The long-term effects described above don’t affect everyone equally. Someone who develops anorexia at 15 and recovers by 18 faces a very different risk profile than someone who is ill for a decade. Duration and severity of illness are the strongest predictors of lasting damage. Some effects, like gastroparesis and menstrual loss, resolve well with sustained nutrition. Others, like bone density loss, dental erosion, and kidney scarring, may be permanent. The cardiovascular and neurological effects fall somewhere in between, improving substantially but not always completely with recovery.