Health Impact

Anorexia's Effects on the Body

Anorexia affects nearly every system in the body, because starvation forces the body to break itself down to survive. The dangers are real — and the heart is the most urgent of them — but there is genuine hope: almost all of anorexia’s medical complications reverse with nutrition and weight restoration. Bone loss is the main lasting exception.

Most effects reverse with recovery — bone loss is the main exception

Written by the Eating Disorder Facts editorial team Awaiting clinical review by Cindy Hawthorn, MD Updated July 20, 2026

Key takeaways

The heart is the most dangerous concern: anorexia slows and weakens it, and cardiac complications are a leading cause of death.
Bone loss (osteopenia and osteoporosis) is the main effect that can be permanent, and it can begin within months.
Hair loss, loss of periods, and brain changes are distressing but largely reverse with recovery.
These effects occur at every body size — a person does not have to look severely underweight to be in medical danger.
Almost all of anorexia’s complications heal with nutrition and weight restoration, which makes recovery deeply restorative.

The most urgent danger

The heart

The heart is a muscle, and in starvation the body breaks down muscle — including heart muscle — for energy. Over time the heart physically shrinks and weakens. Common effects include a dangerously slow heart rate (bradycardia) and low blood pressure, and the weakened heart becomes prone to abnormal rhythms and, ultimately, heart failure. Cardiac complications are among the leading causes of death in anorexia.

This is why medical monitoring — including heart rate, blood pressure, and bloodwork — is central to anorexia care, and why refeeding after severe restriction must be medically supervised. Reassuringly, cardiac function generally improves as weight and nutrition are restored.

The main lasting effect

The bones

Anorexia is hard on the skeleton. Low body weight and low estrogen reduce the body's ability to absorb and retain calcium, weakening the bones — a large majority of people with anorexia develop some bone thinning (osteopenia), and a substantial proportion progress to osteoporosis. This bone loss can begin within months of the illness.

Bone density is the most important exception to anorexia's general pattern of reversibility. While weight restoration helps and can improve bone health, the loss may not fully reverse, and an increased risk of fractures can persist. This is one of the strongest reasons to seek treatment early, before the damage accumulates.

The endocrine system

Hormones, periods, and fertility

Undernutrition disrupts the body's hormones. In those who menstruate, this commonly causes periods to become irregular or stop entirely (amenorrhea). Anorexia affects fertility while the illness is active, but there is good news: with recovery and weight restoration, hormone levels and menstrual cycles typically return, and many people go on to conceive. In a minority of cases these changes are more lasting, which again underscores the value of early treatment.

Cognition and mood

The brain

Starvation affects the brain itself. Imaging studies show reductions in brain gray matter in anorexia, which can contribute to difficulty concentrating, memory problems, rigid thinking, low mood, and slowed processing. As the Minnesota Starvation Experiment demonstrated, an undernourished brain becomes preoccupied and impaired. Encouragingly, these brain changes largely reverse with weight restoration, though some cognitive effects can take time to resolve or occasionally persist.

Visible signs

Hair, skin, and nails

When the body is starved, it prioritizes vital organs over non-essential functions like growing hair — so hair on the head can thin and fall out (a process called telogen effluvium). At the same time, the body may grow fine, downy hair (lanugo) on the face and body in an attempt to stay warm. Skin often becomes dry and nails brittle. These changes are distressing but, unlike bone loss, they reverse: hair regrows and skin recovers as nutrition is restored.

System by system

Digestion and the rest of the body

Anorexia also slows digestion (gastroparesis), causing bloating and constipation, and can lead to anemia, a weakened immune system, muscle wasting, constant coldness, and dangerous electrolyte disturbances. Like most of anorexia's effects, these tend to improve as the body is renourished.

An important caution

These dangers occur at every body size

It is a dangerous myth that only a visibly emaciated person is at medical risk. Every complication described here can occur in someone at a normal or higher weight — this is the reality of atypical anorexia. In fact, the amount and speed of weight loss predicts medical danger better than a person's current weight does. You cannot tell how sick someone is by looking at them.

A hopeful, honest picture

What heals — and what may not

The overarching message is one of hope: almost all of anorexia's medical complications reverse with adequate nutrition and weight restoration. The heart recovers, hormones rebalance, the brain heals, hair regrows, and energy returns. The main exception is bone density, which may not fully recover — which is exactly why earlier treatment matters so much.

None of this damage is cause for shame, and all of it is reason for hope. Learn about anorexia nervosa, its warning signs, and how to find specialized help.

There is hope

The body is remarkably good at healing.

Most of anorexia’s effects reverse with recovery — and the sooner it begins, the more your body can restore. A team can help.

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