Eating disorders are serious, biologically influenced medical illnesses marked by severe disturbances to one’s eating behaviors. Although many people may be concerned about their health, weight, or appearance from time to time, some people become fixated or obsessed with weight loss, body weight or shape, and controlling their food intake. These may be signs of an eating disorder.

Eating disorders are not a choice. These disorders can affect a person’s physical and mental health. In some cases, they can be life-threatening. With treatment, however, people can recover completely from eating disorders.

Eating is essential for survival, and it is no surprise that a drive like hunger exists to ensure that we seek out sustenance. While this page will focus primarily on the physiological mechanisms that regulate hunger and eating, powerful social, cultural, and economic influences also play important roles.

Physiological Mechanisms

There are a number of physiological mechanisms that serve as the basis for hunger. When our stomachs are empty, they contract. Typically, a person then experiences hunger pangs. Chemical messages travel to the brain, and serve as a signal to initiate feeding behavior. When our blood glucose levels drop, the pancreas and liver generate a number of chemical signals that induce hunger (Konturek et al., 2003; Novin, Robinson, Culbreth, & Tordoff, 1985) and thus initiate feeding behavior.

For most people, once they have eaten, they feel satiation, or fullness and satisfaction, and their eating behavior stops. Like the initiation of eating, satiation is also regulated by several physiological mechanisms. As blood glucose levels increase, the pancreas and liver send signals to shut off hunger and eating (Drazen & Woods, 2003; Druce, Small, & Bloom, 2004; Greary, 1990). The food’s passage through the gastrointestinal tract also provides important satiety signals to the brain (Woods, 2004), and fat cells release leptin, a satiety hormone.

The various hunger and satiety signals that are involved in the regulation of eating are integrated in the brain. Research suggests that several areas of the hypothalamus and hindbrain are especially important sites where this integration occurs (Ahima & Antwi, 2008; Woods & D’Alessio, 2008). Ultimately, activity in the brain determines whether or not we engage in feeding behavior.

Metabolism and Body Weight

Our body weight is affected by a number of factors, including gene-environment interactions, and the number of calories we consume versus the number of calories we burn in daily activity. If our caloric intake exceeds our caloric use, our bodies store excess energy in the form of fat. If we consume fewer calories than we burn off, then stored fat will be converted to energy. Our energy expenditure is obviously affected by our levels of activity, but our body’s metabolic rate also comes into play. A person’s metabolic rate is the amount of energy that is expended in a given period of time, and there is tremendous individual variability in our metabolic rates. People with high rates of metabolism are able to burn off calories more easily than those with lower rates of metabolism.

We all experience fluctuations in our weight from time to time, but generally, most people’s weights fluctuate within a narrow margin, in the absence of extreme changes in diet and/or physical activity. This observation led some to propose a set-point theory of body weight regulation. The set-point theory asserts that each individual has an ideal body weight, or set point, which is resistant to change. This set-point is genetically predetermined and efforts to move our weight significantly from the set-point are resisted by compensatory changes in energy intake and/or expenditure (Speakman et al., 2011).

Some of the predictions generated from this particular theory have not received empirical support. For example, there are no changes in metabolic rate between individuals who had recently lost significant amounts of weight and a control group (Weinsier et al., 2000). In addition, the set-point theory fails to account for the influence of social and environmental factors in the regulation of body weight (Martin-Gronert & Ozanne, 2013; Speakman et al., 2011). Despite these limitations, set-point theory is still often used as a simple, intuitive explanation of how body weight is regulated.

Obesity

When someone weighs more than what is generally accepted as healthy for a given height, they are considered overweight or obese. According to the Centers for Disease Control and Prevention (CDC), an adult with a body mass index (BMI) between 25 and 29.9 is considered overweight. An adult with a BMI of 30 or higher is considered obese (Centers for Disease Control and Prevention [CDC], 2012). People who are so overweight that they are at risk for death are classified as morbidly obese. Morbid obesity is defined as having a BMI over 40. Note that although BMI has been used as a healthy weight indicator by the World Health Organization (WHO), the CDC, and other groups, its value as an assessment tool has been questioned. The BMI is most useful for studying populations, which is the work of these organizations. It is less useful in assessing an individual since height and weight measurements fail to account for important factors like fitness level. An athlete, for example, may have a high BMI because the tool doesn’t distinguish between the body’s percentage of fat and muscle in a person’s weight.

Being extremely overweight or obese is a risk factor for several negative health consequences. These include, but are not limited to, an increased risk for cardiovascular disease, stroke, Type 2 diabetes, liver disease, sleep apnea, colon cancer, breast cancer, infertility, and arthritis. Given that it is estimated that in the United States around one-third of the adult population is obese and that nearly two-thirds of adults and one in six children qualify as overweight (CDC, 2012), there is substantial interest in trying to understand how to combat this important public health concern.

What causes someone to be overweight or obese? You have already read that both genes and environment are important factors for determining body weight, and if more calories are consumed than expended, excess energy is stored as fat. However, socioeconomic status and the physical environment must also be considered as contributing factors (CDC, 2012). For example, an individual who lives in an impoverished neighborhood that is overrun with crime may never feel comfortable walking or biking to work or to the local market. This might limit the amount of physical activity in which he engages and result in an increased body weight. Similarly, some people may not be able to afford healthy food options from their market, or these options may be unavailable (especially in urban areas or poorer neighborhoods); therefore, some people rely primarily on available, inexpensive, high fat, and high calorie fast food as their primary source of nutrition.

Generally, overweight and obese individuals are encouraged to try to reduce their weights through a combination of both diet and exercise. While some people are very successful with these approaches, many struggle to lose excess weight. In cases in which a person has had no success with repeated attempts to reduce weight or is at risk for death because of obesity, bariatric surgery may be recommended. Bariatric surgery is a type of surgery specifically aimed at weight reduction, and it involves modifying the gastrointestinal system to reduce the amount of food that can be eaten and/or limiting how much of the digested food can be absorbed (Mayo Clinic, 2013). A recent meta-analysis suggests that bariatric surgery is more effective than non-surgical treatment for obesity in the two-years immediately following the procedure, but to date, no long-term studies yet exist (Gloy et al., 2013).

Disordered eating describes unhealthy eating patterns that can increase risk for health problems (e.g., bone loss, poor nutrition). Disordered eating can also increase risk for mental health issues, including depression or an eating disorder diagnosis.

Signs of disordered eating may include:

• Yo-yo dieting or excessive calorie counting
• Anxiety around certain foods
• Rigid routines for eating and exercise
• Feelings of guilt and shame associated with eating, weight and body image
• Inability to control eating
• Hyper focus on food in a way that it negatively affects one's life
• Body weight going up and down
• Use of food to cope with emotions or stress
• Use of exercise or fasting to make up for overeating

An eating disorder is a more severe diagnosed mental health condition. Symptoms of an eating disorder include disordered eating behaviors. Eating disorders can include:

• Anorexia nervosa (intense fear of gaining weight and desire to lose weight by not eating)
• Bulimia nervosa (recurrent episodes of overeating and purging behavior, such as self-induced vomiting)
• Binge eating disorder (excessive and repetitive loss of control eating)

How do you feel after you eat? Satisfied? Too full? Or maybe even guilty? Being too focused on food can sometimes turn into an eating disorder.

People with eating disorders have severe, persistent, and unhealthy thoughts and behaviors about food. As a result, they might eat way too little or way too much.

Eating disorders are not a lifestyle choice. They are serious illnesses. They affect your body’s ability to get proper nutrition. This can lead to health issues, such as heart and kidney problems, or even death.

The three most widely recognized eating disorders are binge-eating disorder, bulimia nervosa, and anorexia nervosa. Binge-eating disorder is the most common eating disorder in the United States.

“Binge-eating is not just a lot of overeating,” explains Dr. Cynthia Bulik, an expert on eating disorders at the University of North Carolina at Chapel Hill. “There’s this sense of loss of control. You start eating and you feel like you just can’t stop.”

People with binge-eating disorder eat well beyond being full. They often eat until they feel very uncomfortable. Afterward, they’re usually overcome by feelings of guilt, shame, and distress. Eating too much too often can lead to weight gain and can be associated with obesity.

When binge-eating is followed by “purging,” it’s called bulimia nervosa. People with bulimia nervosa may follow binge-eating by vomiting or taking laxatives to purge, over-exercising, or fasting. They’re often able to maintain a normal weight because they compensate for the extra calories. But bulimia nervosa can cause other health issues, like heart irregularities or problems with the digestive system.

People with anorexia nervosa are on the other extreme. They eat very little. They may see themselves as overweight, even when they are dangerously underweight. It’s the least common of the three eating disorders, but is often the most deadly.

An eating disorder can develop for anyone, at any body weight or shape, and at any time. But they often start in the teen or young adult years.

“When young people show signs of an eating disorder, there is this tendency to think that they might outgrow it or that it’s just a phase,” Bulik says. “But the most likely path is in the direction of developing a full-blown eating disorder.”

What causes eating disorders isn’t known. Genes and family history, mental and emotional health, and environment and culture can all influence whether someone develops one of these complex conditions. Some NIH-funded researchers are studying possible genetic causes for eating disorders. Others are looking for changes in the brain. They hope their studies will help guide how eating disorders are diagnosed and treated.

Many people with eating disorders may not think they need treatment. So family members and friends can be very helpful. Express concern. Say you’re there to listen.

“If you’re concerned that you or a family member might have an eating disorder, the key is really to see a health professional with expertise in eating disorders for an evaluation,” Bulik says.

Treatment plans are tailored to individual needs. They may include talk therapy, nutritional counseling, and medications. With treatment, you can return to healthier eating habits and prevent serious complications.

Unhealthy Eating Habits

You can’t tell by someone’s size if they have an eating disorder. But you can look for certain signs:

• Skipping meals, making excuses for not eating, or eating in secret or separately.
• Persistent worrying or talking about healthy eating, exercise, being overweight, or losing weight.
• Eating much more food in a meal or snack than what’s considered normal.
• Eating large amounts of sweets or high-fat foods.
• Leaving during meals to use the toilet.
• Expressing depression, disgust, shame, or guilt about eating habits.
• Frequently checking the mirror for perceived flaws.

What are eating disorders?

Eating disorders are serious mental health disorders. They involve severe problems with your thoughts about food and your eating behaviors. You may eat much less or much more than you need.

Eating disorders are medical conditions; they are not a lifestyle choice. They affect your body's ability to get proper nutrition. This can lead to health issues, such as heart and kidney problems, or sometimes even death. But there are treatments that can help.

What are the types of eating disorders?

Common types of eating disorders include

• Binge-eating, which is out-of-control eating. People with binge-eating disorder keep eating even after they are full. They often eat until they feel very uncomfortable. Afterward, they usually have feelings of guilt, shame, and distress. Eating too much too often can lead to weight gain and obesity. Binge-eating disorder is the most common eating disorder in the U.S.
• Bulimia nervosa. People with bulimia nervosa also have periods of binge-eating. But afterwards, they purge, by making themselves throw up or using laxatives. They may also over-exercise or fast. People with bulimia nervosa may be slightly underweight, normal weight, or overweight.
• Anorexia nervosa. People with anorexia nervosa avoid food, severely restrict food, or eat very small quantities of only certain foods. They may see themselves as overweight, even when they are dangerously underweight. Anorexia nervosa is the least common of the three eating disorders, but it is often the most serious. It has the highest death rate of any mental disorder.

What causes eating disorders?

The exact cause of eating disorders is unknown. Researchers believe that eating disorders are caused by a complex interaction of factors. These include genetic, biological, behavioral, psychological, and social factors.

Who is at risk for eating disorders?

Anyone can develop an eating disorder, but they are more common in women. Eating disorders frequently appear during the teen years or young adulthood. But people can also develop them during childhood or later in life.

What are the symptoms of eating disorders?

The symptoms of eating disorders vary, depending on the disorder:

The symptoms of binge-eating include

• Eating unusually large amounts of food in a specific amount of time, such as a 2-hour period
• Eating even when you're full or not hungry
• Eating fast during binge episodes
• Eating until you're uncomfortably full
• Eating alone or in secret to avoid embarrassment
• Feeling distressed, ashamed, or guilty about your eating
• Frequently dieting, possibly without weight loss

The symptoms of bulimia nervosa include the same symptoms as binge-eating, plus trying to get rid of the food or weight after binging by

• Purging, making yourself throw up or using laxatives or enemas to speed up the movement of food through your body
• Doing intensive and excessive exercise
• Fasting

Over time, bulimia nervosa can cause health problems such as

• Chronically inflamed and sore throat
• Swollen salivary glands in the neck and jaw area
• Worn tooth enamel and increasingly sensitive and decaying teeth. This is caused by the exposure to stomach acid every time you throw up.
• GERD (acid reflux) and other gastrointestinal problems
• Severe dehydration from purging
• Electrolyte imbalance, which could be too low or too high levels of sodium, calcium, potassium and other minerals. This can lead to a stroke or heart attack.

The symptoms of anorexia nervosa include

• Eating very little, to the point of starving yourself
• Intensive and excessive exercise
• Extreme thinness
• Intense fear of gaining weight
• Distorted body image - seeing yourself as overweight even when you are severely underweight

Over time, anorexia nervosa can cause health problems such as

• Thinning of the bones (osteopenia or osteoporosis)
• Mild anemia
• Muscle wasting and weakness
• Thin, brittle hair and nails
• Dry, blotchy, or yellowish skin
• Growth of fine hair all over the body
• Severe constipation
• Low blood pressure
• Slowed breathing and pulse
• Feeling cold all the time because of a drop in internal body temperature
• Feeling faint, dizzy, or weak
• Feeling tired all the time
• Infertility
• Damage to the structure and function of the heart
• Brain damage
• Multiorgan failure

Anorexia nervosa can be fatal. Some people with this disorder die of complications from starvation, and others die of suicide.

Some people with eating disorders may also have other mental disorders (such as depression or anxiety) or problems with substance use.

How is eating disorders diagnosed?

Because eating disorders can be so serious, it is important to seek help if you or a loved one thinks that you might have a problem. Your health care provider may use many tools to make a diagnosis:

• A medical history, which includes asking about your symptoms. It is important to be honest about your eating and exercise behaviors so your provider can help you.
• A physical exam
• Blood or urine tests to rule out other possible causes of your symptoms
• Other tests to see whether you have any other health problems caused by the eating disorder. These can include kidney function tests and an electrocardiogram (EKG or ECG).

What are the treatments for eating disorders?

Treatment plans for eating disorders are tailored to individual needs. You will likely have a team of providers helping you, including doctors, nutritionists, nurses, and therapists. The treatments may include

• Individual, group, and/or family psychotherapy. Individual therapy may include cognitive behavioral approaches, which help you to identify and change negative and unhelpful thoughts. It also helps you build coping skills and change behavioral patterns.
• Medical care and monitoring, including care for the complications that eating disorders can cause
• Nutrition counseling. Doctors, nurses, and counselors will help you eat healthy to reach and maintain a healthy weight.
• Medicines, such as antidepressants, antipsychotics, or mood stabilizers, may help treat some eating disorders. The medicines can also help with the depression and anxiety symptoms that often go along with eating disorders.

Some people with serious eating disorders may need to be in a hospital or in a residential treatment program. Residential treatment programs combine housing and treatment services.

Eating disorders can affect people of all ages, racial/ethnic backgrounds, body weights, and genders. Although eating disorders often appear during the teen years or young adulthood, they may also develop during childhood or later in life (40 years and older).

Remember: People with eating disorders may appear healthy, yet be extremely ill.

The exact cause of eating disorders is not fully understood, but research suggests a combination of genetic, biological, behavioral, psychological, and social factors can raise a person’s risk.

Common eating disorders include anorexia nervosa, bulimia nervosa, binge-eating disorder, and avoidant restrictive food intake disorder. Each of these disorders is associated with different but sometimes overlapping symptoms. People exhibiting any combination of these symptoms may have an eating disorder and should be evaluated by a health care provider.

What is anorexia nervosa?

Anorexia nervosa is a condition where people avoid food, severely restrict food, or eat very small quantities of only certain foods. They also may weigh themselves repeatedly. Even when dangerously underweight, they may see themselves as overweight.

There are two subtypes of anorexia nervosa: a restrictive subtype and a binge-purge subtype.

Restrictive: People with the restrictive subtype of anorexia nervosa severely limit the amount and type of food they consume.

Binge-Purge: People with the binge-purge subtype of anorexia nervosa also greatly restrict the amount and type of food they consume. In addition, they may have binge-eating and purging episodes—eating large amounts of food in a short time followed by vomiting or using laxatives or diuretics to get rid of what was consumed.

Symptoms of anorexia nervosa include:

• Extremely restricted eating and/or intensive and excessive exercise
• Extreme thinness (emaciation)
• A relentless pursuit of thinness and unwillingness to maintain a normal or healthy weight
• Intense fear of gaining weight
• Distorted body or self-image that is heavily influenced by perceptions of body weight and shape
• Denial of the seriousness of low body weight

Over time, anorexia nervosa can lead to numerous serious health consequences, including:

• Thinning of the bones (osteopenia or osteoporosis)
• Mild anemia
• Muscle wasting and weakness
• Brittle hair and nails
• Dry and yellowish skin
• Growth of fine hair all over the body (lanugo)
• Severe constipation
• Low blood pressure
• Slowed breathing and pulse
• Damage to the structure and function of the heart
• Drop in internal body temperature, causing a person to feel cold all the time
• Lethargy, sluggishness, or feeling tired all the time
• Infertility
• Brain damage
• Multiple organ failure

Anorexia nervosa can be fatal. It has an extremely high death (mortality) rate compared with other mental disorders. People with anorexia are at risk of dying from medical complications associated with starvation. Suicide is the second leading cause of death for people diagnosed with anorexia nervosa.

If you or someone you know is in immediate distress or is thinking about hurting themselves, call the National Suicide Prevention Lifeline toll-free at 1-800-273-TALK (8255). You also can text the Crisis Text Line (HELLO to 741741) or use the Lifeline Chat on the National Suicide Prevention Lifeline website. If you suspect a medical emergency, seek medical attention or call 911 immediately.

What is bulimia nervosa?

Bulimia nervosa is a condition where people have recurrent episodes of eating unusually large amounts of food and feeling a lack of control over their eating. This binge eating is followed by behaviors that compensate for the overeating to prevent weight gain, such as forced vomiting, excessive use of laxatives or diuretics, fasting, excessive exercise, or a combination of these behaviors. Unlike those with anorexia nervosa, people with bulimia nervosa may maintain a normal weight or be overweight.

Symptoms and health consequences of bulimia nervosa include:

• Chronically inflamed and sore throat
• Swollen salivary glands in the neck and jaw area
• Worn tooth enamel and increasingly sensitive and decaying teeth from exposure to stomach acid when vomiting
• Acid reflux disorder and other gastrointestinal problems
• Intestinal distress and irritation from laxative abuse
• Severe dehydration from purging
• Electrolyte imbalance (too low or too high levels of sodium, calcium, potassium, and other minerals), which can lead to stroke or heart attack

What is binge-eating disorder?

Binge-eating disorder is a condition where people lose control of their eating and have reoccurring episodes of eating unusually large amounts of food. Unlike bulimia nervosa, periods of binge eating are not followed by purging, excessive exercise, or fasting. As a result, people with binge-eating disorder are often overweight or obese.

Symptoms of binge-eating disorder include:

• Eating unusually large amounts of food in a short amount of time, for example, within two hours
• Eating rapidly during binge episodes
• Eating even when full or not hungry
• Eating until uncomfortably full
• Eating alone or in secret to avoid embarrassment
• Feeling distressed, ashamed, or guilty about eating
• Frequently dieting, possibly without weight loss

What is avoidant restrictive food intake disorder?

Avoidant restrictive food intake disorder (ARFID), previously known as selective eating disorder, is a condition where people limit the amount or type of food eaten. Unlike anorexia nervosa, people with ARFID do not have a distorted body image or extreme fear of gaining weight. ARFID is most common in middle childhood and usually has an earlier onset than other eating disorders. Many children go through phases of picky eating, but a child with ARFID does not eat enough calories to grow and develop properly, and an adult with ARFID does not eat enough calories to maintain basic body function.

Symptoms of ARFID include:

• Dramatic restriction of types or amount of food eaten
• Lack of appetite or interest in food
• Dramatic weight loss
• Upset stomach, abdominal pain, or other gastrointestinal issues with no other known cause
• Limited range of preferred foods that becomes even more limited (“picky eating” that gets progressively worse)

Eating disorders can be treated successfully. Early detection and treatment are important for a full recovery. People with eating disorders are at higher risk for suicide and medical complications.

A person’s family can play a crucial role in treatment. Family members can encourage the person with eating or body image issues to seek help. They also can provide support during treatment and can be a great ally to both the individual and the health care provider. Research suggests that incorporating the family into treatment for eating disorders can improve treatment outcomes, particularly for adolescents.

Treatment plans for eating disorders include psychotherapy, medical care and monitoring, nutritional counseling, medications, or a combination of these approaches. Typical treatment goals include:

• Restoring adequate nutrition
• Bringing weight to a healthy level
• Reducing excessive exercise
• Stopping binge-purge and binge-eating behaviors

People with eating disorders also may have other mental disorders (such as depression or anxiety) or problems with substance use. It’s critical to treat any co-occurring conditions as part of the treatment plan.

Specific forms of psychotherapy (“talk therapy”) and cognitive-behavioral approaches can treat certain eating disorders effectively.

Research also suggests that medications may help treat some eating disorders and co-occurring anxiety or depression related to eating disorders. Information about medications changes frequently, so talk to your health care provider.

The way we talk about eating disorders matters. Here are some facts you can use to help shape the conversation around eating disorders.

“Eating disorders are medical illnesses.”

Genetic and environmental factors can influence eating disorders. An eating disorder is not a trend or a choice.

“Eating disorders are serious and can be fatal.”

Eating disorders often involve serious medical complications that can cause permanent damage or death. People with eating disorders also have an increased risk of dying by suicide.

“Eating disorders can affect anyone.”

Eating disorders do not discriminate. They affect people of all ages, races and ethnicities, and genders.

“You can’t tell if someone has an eating disorder by looking at them.”

People with eating disorders can be underweight, normal weight, or overweight.

“Family members can be a patient’s best ally in treatment.”

Eating disorders are caused by a combination of genetic, biological, behavioral, psychological, and social factors. Family members do not cause eating disorders and can be great sources of support.

“It is possible to recover from an eating disorder.”

Complete recovery is possible with treatment and time.