Eating Disorders – Symptoms and Causes

Eating Disorders


Eating disorders involve serious disturbances in eating behavior, including unhealthy reduction of food intake, severe overeating and/or dangerous methods to prevent weight gain, such as self-induced vomiting. Severe eating disorders may result in serious health consequences including death.

Patients can be diagnosed with an eating disorder at any age, but they most often develop during adolescence and young adulthood. More women than men are diagnosed with eating disorders.

The most common types of eating disorders are anorexia nervosa, bulimia nervosa and binge eating disorder. Other, less common types of eating disorders include pica and rumination disorder.

In addition, some patients may have an eating disorder that does not fit the criteria for any of the recognized eating disorders. In such cases, a diagnosis known as “eating disorder not otherwise specified” (EDNOS) may be made.

The exact cause of eating disorders is not known, but they are believed to result from a combination of genetic, psychological and environmental factors. Most recently, researchers are studying the possibility of biochemical or biological causes for the development of eating disorders. Some patients with eating disorders exhibit imbalances in certain chemicals in the brain that control hunger and appetite.Eating disorders are also believed to be contributed to in part from a media environment that celebrates levels of thinness that may be impossible to maintain. According to a 2005 Youth Risk Behavior Study, 61 percent of adolescent girls were trying to lose weight.

Patients with eating disorders frequently have other types of mental health disorders including depression, anxiety disorders (e.g., obsessive-compulsive disorder) and substance abuse. They often exhibit symptoms including an excessive preoccupation with food, extreme unhappiness or concern about body shape and size, menstrual irregularities, excessive exercise routines and chronic fatigue.

Eating disorders are usually diagnosed after a physical examination, including a complete medical history. The physician may check the patient’s vital signs and perform tests (e.g., blood tests) to rule out medical conditions that may be causing symptoms. The physician will also ask about the patient’s history of dieting and/or eating patterns, as well as assess their attitude toward food and weight gain/loss. Once an eating disorder is diagnosed, a physician may refer the patient to a mental and/or behavioral health specialist (typically a psychiatrist) for further evaluation and treatment.

Due to their complex nature, eating disorders usually require a comprehensive treatment plan including medical care and monitoring of health complications (e.g., malnutrition, obesity), psychotherapy and dietary counseling by a nutritionist.

Receiving support from family members and friends is important because often patients with eating disorders are in denial and resist treatment, believing they do not need help.

The outlook for patients with eating disorders is generally favorable with early treatment.

About eating disorders

Eating a balanced and healthful diet is crucial for the normal functioning of all organ systems. Disordered eating habits (e.g., skipping meals) or prolonged dieting (e.g., calorie restriction) may deplete the body of important nutrients and can lead to malnutrition. In some cases, such habits may become chronic and may lead to the development of an eating disorder.

Eating disorders involve serious disturbances in eating behavior, including unhealthy reduction of food intake or severe overeating, in addition to extreme unhappiness or concern about body shape and weight. Oftentimes, individuals with eating disorders (e.g., anorexia nervosa, bulimia nervosa) associate their self-worth or self-esteem with the way their bodies look and attempt to control their weight through harmful methods such as starvation and purging (e.g., self-induced vomiting). In some cases, people may feel no self-control when it comes to food and may gorge themselves until they are uncomfortably full (binge eating).

Generally, eating disorders co-exist with other psychological disorders including depression, anxiety disorders (e.g., obsessive-compulsive disorder) and substance abuse. Females are more likely than males to develop eating disorders. According to the U.S. Department of Health and Human Services, more than 90 percent of patients with eating disorders are female. Eating disorders typically begin during adolescence or early adulthood. However, in some cases they may develop before adolescence as well as during middle age (at age 40 or older). Eating disorders are more common in industrialized, economically developed nations. Currently, between 1 and 4 percent of all young women in the United States have some type of eating disorder. Eating disorders are dangerous because food is vital for sustaining all bodily functions. Individuals with prolonged eating disorders may develop malnutrition that can become life-threatening if left untreated. Oftentimes, people with eating disorders are in denial and do not recognize or admit that there may be a problem and as a result, may become extremely resistant to seeking medical treatment. In such cases, the intervention of family members, teachers or peers may be necessary to ensure that the individual suspected of having an eating disorder receives proper medical attention.

Types and differences of eating disorders

Eating disorders are generally characterized by an obsessive preoccupation with weight and/or food that results in extreme disturbances in eating and other behaviors. These disorders are often chronic and dangerous because they can severely compromise a person’s health.

The three most common types of eating disorders include:

  • Anorexia nervosa. This eating disorder is basically self-starvation.  To be diagnosed with anorexia nervosa, a person must weigh more than 15 percent below the normal range for their age and body size and exhibit a distorted body image, including a sometimes intense fear of gaining weight. People with anorexia nervosa usually lose weight by drastically reducing their food intake (fewer than 1,000 calories per day) and through excessive exercise (anorexia athletica). Among adolescents, anorexia may also be present when a person fails to gain age-appropriate weight during puberty and post-puberty, even if he or she is not losing much weight. According to the U.S. Department of Health and Human Services, it ranks as the third most common chronic illness among adolescent girls in the nation.

    Anorexia nervosa has severe, life-threatening complications. Prolonged starvation can lead to malnutrition and damage of the vital organs, including the heart and brain. In addition, nutritional deprivation often results in the loss of bone mass (osteoporosis), which may result in brittle bones that break easily. Other complications include amenorrhea (loss of menstrual periods), anemia (low red blood cell count), hair loss, infertility (inability to get pregnant) and a failure to grow to normal stature in children or adolescents. If left untreated, patients with anorexia nervosa may literally starve themselves to death.

  • Bulimia nervosa. Also called bulimia or binge-purge syndrome, this eating disorder is characterized by a pattern of binge eating followed by harmful behaviors to control or prevent any resulting weight gain. Binge eating is defined as the consumption of excessive amounts of food in a short time period. The food is often high in calories and easy to consume (e.g., ice cream). Typically, people with bulimia purge themselves of eaten food by either self-induced vomiting or the use of laxatives (usually mild drugs for stimulating bowel movement), diuretics or, rarely, enemas (injecting liquid into the intestines through the anus to empty the bowels). To be diagnosed with bulimia, these types of behaviors must have occurred on average a minimum of two times a week for three months.

    Patients with bulimia may cause harm to their bodies with frequent episodes of binging and purging. Complications of bulimia include electrolyte imbalance (a loss of vitamins and minerals that are crucial for normal organ functioning, such as potassium) and dehydration (loss of water), which may lead to weakness and irregular heart rhythms. Other complications include tooth and gum decay caused by the acids contained in the vomit, digestive problems (e.g., constipation) and medication abuse (e.g., diuretics, stimulants, diet pills). In prolonged or severe cases, binge eating may cause the stomach to rupture and chronic purging may result in heart failure.

  • Binge eating disorder (BED). This disorder, which is a research diagnosis is not yet fully accepted, is mainly identified by recurring episodes of uncontrolled, rapid eating, often followed by remorse and guilt. The binging or overeating typically does not stop until the person is uncomfortably full, and the person usually eats alone because of embarrassment. BED differs from anorexia nervosa and bulimia nervosa in that it is not associated with purging behaviors (e.g., self-induced vomiting, use of laxatives) to avoid the weight gain. However, individuals with this type of eating disorder sometimes may engage in chronic dieting attempts and/or fasting. Also, BED may sometimes be difficult to differentiate from overweight or obesity. Individuals with BED often feel out of control when it comes to their binges and have accompanying feelings of depression, guilt and self-disgust.

    Complications of binge eating disorder include obesity, high blood pressure, high cholesterol levels, heart disease, type 2 diabetes (uncontrolled blood sugar) and gallbladder disease (inflammation or infection of the sac gallbladder, which helps digest fats).

Other less common types of eating disorders include:

  • Pica. This eating disorder involves the chronic craving and consumption of nonfood items including dirt, clay, paint chips, chalk, cornstarch, baking soda, coffee grounds, cigarette ashes or butts, burnt match heads, feces, ice, glue, hair, buttons, paper, sand, toothpaste and soap. Pica occurs more often in people with developmental disabilities (e.g., autism, mental retardation), children between the ages of 2 and 3 years and, sometimes, pregnant women. Even though infants younger than 18 months to 24 months may try to eat nonfood items, it is generally not considered abnormal at that age. In most cases, toddlers spontaneously outgrow the disorder and, in pregnant women, pica usually resolves after giving birth.

    Complications of pica may include lead poisoning (from eating paint chips in older buildings with lead-based paint), bowel problems, intestinal obstruction or perforation, dental injury, parasitic infections and malnutrition. Sometimes, this eating disorder may be life-threatening if a patient consumes a toxic or lethal substance. Also, pregnant women with the disorder may cause harm to their fetus if they consume harmful substances.

  • Rumination disorder. An eating disorder characterized by the repeated regurgitation (throwing up) and re-chewing of partially digested food, which is then re-swallowed or expelled. In rumination, regurgitation appears effortless and may be preceded by a belching sensation and usually does not involve nausea or vomiting. This disorder is more common in infants and individuals with severe and profound mental retardation. However, it generally resolves itself spontaneously in healthy infants with the disorder.

    Complications of rumination include dehydration and electrolyte imbalance, gastric problems, upper respiratory distress, dental problems (e.g., tooth decay), aspiration (deviation of food into the lungs), choking, pneumonia (inflammation of the lungs) and malnutrition.

In addition, some patients may have an eating disorder that does not fit the criteria for any of the recognized eating disorders. In such cases, a diagnosis known as “eating disorder not otherwise specified” (EDNOS) may be made. In EDNOS, individuals engage in some form of abnormal eating behavior but do not exhibit all the specific symptoms required to diagnose an eating disorder. For instance, a female with EDNOS may meet all the criteria of anorexia nervosa but despite the significant weight loss, she manages to maintain a normal weight or has regular menstrual periods.

Risk factors and causes of eating disorders

The exact cause of eating disorders is not known. Perhaps part of the explanation for their prevalence in economically developed nations may be media messages regarding ideals of beauty and attractiveness. These messages often promote thinness as the female ideal. In order to be thin or slender, some people strive to maintain a weight that may not be healthy for their bodies. In some cases, though, it is possible to be slender and healthy at the same time. However, it becomes a serious health problem when people use detrimental methods (e.g., starvation) to achieve the desired results.

Generally, a combination of various factors may contribute to the development of eating disorders. These include:

  • Gender. Females are more likely to develop eating disorders than males. One reason females may be at greater risk for developing eating disorders is their tendency to go on strict diets to achieve the “ideal” thin figure, which is often promoted by the media. According to a 2005 Youth At Risk Behavior Survey, 61 percent of adolescent girls are trying to lose weight and 32 percent believe they are overweight.However, eating disorders do occur in males. According to the U.S. National Institute of Mental Health(NIMH), an estimated 5 to 15 percent of people with anorexia nervosa or bulimia nervosa and approximately 35 percent of those with binge eating disorder are male.

  • Age. Even though eating disorders may occur at any age, they are much more common among teenagers and young adults (people in their 20s and early 30s).

  • Heredity. Eating disorders are more common among people with close family members with eating disorders. Current also research indicates that there are significant genetic contributions to the development of eating disorders.

  • Mental illnesses. Oftentimes, people with eating disorders have other types of psychological illnesses including depression, anxiety disorders (e.g., obsessive-compulsive disorder) and substance abuse. The presence of a pre-existing emotional disorder often reinforces the eating disorder and vice versa.

  • Low self-esteem and feelings of inadequacy or lack of control in life.

  • Stress. Eating disorders also may be triggered by stressful situations and/or traumatic events including a history of abuse (e.g., physical, sexual), dysfunctional family, divorce, death of a family member or friend or starting a new school or job.

  • Family and social influences. Individuals whose parents, siblings or other close family members and friends are overly critical of their weight, appearance and/or eating habits may be at increased risk of using harmful methods for weight control (e.g., purging) that can lead to the development of an eating disorder.

  • Competitive sports and performance arts. People, especially females, who participate in highly competitive athletic activities (e.g., ballet, gymnastics) or work in the entertainment industry (e.g., actors, models) may be at greater risk of using harmful methods (e.g., starvation, abusing diet pills) for weight control due to the strict weight requirements of certain sports or performance arts. Prolonged use of such methods can put individuals at risk of developing eating disorders. 

In addition, recent studies indicate that some patients with eating disorders may have imbalances in chemicals in the brain that control, hunger, appetite and digestion. However, further research is necessary before the exact meaning and implications of these imbalances in regards to eating disorders can be established.

Signs and symptoms of eating disorders

The signs and symptoms of eating disorders vary depending upon which type of eating disorder is present. Generally, individuals with eating disorders may exhibit signs such as rapid weight loss or weight fluctuations, excessive or compulsive exercising and episodes of chronic binge eating that may or may not be followed by fasting and/or purging behaviors (e.g., self-induced vomiting, diuretics). Other symptoms include chronic fatigue or lightheadedness, menstrual irregularities, dehydration, hair loss, swollen cheeks (from self-induced vomiting), dental problems (e.g., tooth and gum decay), bowel problems, depression, irritability or insomnia.

The signs of pica, a less common type of eating disorder, which is characterized by the chronic craving and consumption of nonfood items (e.g., dirt, clay), include dental injuries, abdominal pain, diarrhea and/or constipation in addition to recurrent infections or parasitic infestations.

The signs and symptoms of rumination disorder, another less common type of eating disorder, include:

  • Chronic and effortless regurgitation that typically begins within minutes of a meal and may last for several hours

  • Repeated re-chewing of food

  • Unexplained weight loss, growth failure (in children)

  • Bad breath (halitosis)

  • Indigestion

  • Dental problems (e.g., tooth decay and erosion)

  • Raw or chapped lips

  • Vomit residue on the individual’s chin, neck or upper clothing

Diagnosis methods for eating disorders

Physicians generally diagnose eating disorders based on the patient’s symptoms and eating habits. During an initial consultation, a physician will record the patient’s weight and perform a thorough physical examination including:

  • Checking vital signs, such as heart rate, blood pressure and temperature

  • Evaluation of patient’s skin, abdomen and teeth

  • Neurological examination to evaluate other potential causes of weight loss or vomiting, such as a brain tumor

A physician will also compile a comprehensive medical history including family history of physical and psychological disorders (e.g., depression, obsessive-compulsive disorder) as well as inquire into the patient’s history of dieting and/or eating patterns. Some of the questions a physician may ask include:

  • Have you recently lost more than 14 pounds (6.35 kg) in a three-month period?

  • Do you believe you are fat when others say you are too thin?

  • Would you say that food dominates your life?

  • Do you make yourself sick because you feel uncomfortably full?

  • Do you ever eat in secret?

  • Does your weight affect the way you feel about yourself?

In addition, a physician may order diagnostic tests to identify any signs of complications of eating disorders including malnutrition, anemia (reduced blood cell count), unusual heart rhythms, digestive problems (e.g., constipation, diarrhea), bone density loss or changes in the menstrual cycle.

Additional diagnostic tests may include:

  • Blood tests. Laboratory analyses – including a complete blood count (CBC) – of blood samples to measure levels of hormones, enzymes, proteins, electrolytes, vitamins and other substances. Blood tests assess the function of various organ systems including the liver, kidney, thyroid and pituitary glands as well as the ovaries (female reproductive glands).

  • Urinalysis. Chemical examination of a patient’s urine sample to screen for urinary tract infections, kidney disease and diseases of other organs that result in the appearance of abnormal metabolites (break-down products) in the urine.

  • Electrocardiogram (EKG). This test measures the pattern of electrical impulses generated by the heart. During the procedure, electrodes (devices that detect electrical impulses) are attached to the patient’s chest. The electrical impulses are then recorded on a graph. In patients with eating disorders, an EKG can help detect irregular heartbeats and identify the presence of any damage to the heart.

  • Imaging tests (e.g., x-ray, CAT scan, MRI). These tests are useful in detecting the presence of any damage in the chest, digestive tract, brain and other organs caused by eating disorders. For example, a chest x-ray may reveal whether the eating disorder has damaged the heart muscles by reducing the size of the heart.

  • Bone density test. During this test, a physician may use a device called a sonometer to pass painless sound waves through the bones to measure the density of the bones and check for signs of bone mass loss (osteoporosis).

Once an eating disorder is diagnosed, a physician may refer the patient to a mental and/or behavioral health specialist (typically a psychiatrist) for further evaluation and treatment. Patients may also be referred to a nutritionist (a licensed nutrition expert) and/or dentist for the treatment of dental complications, such as tooth and gum decay.

Treatment options for eating disorders

The sooner an individual with an eating disorder is diagnosed and begins treatment, the better the outcome is likely to be. Due to their complexity, eating disorders usually require a comprehensive treatment plan including medical care and monitoring of health complications (e.g., malnutrition, obesity), psychological evaluation, behavior therapy and dietary counseling. In severe cases of malnutrition, immediate hospitalization of the patient may be necessary to rehydrate and restore electrolyte imbalance through intravenous (into a vein) feeding.

Often, people with eating disorders are in denial and may refuse to recognize that there is a problem. Many times, they may resist getting and staying in treatment. Family members and other individuals close to the person suspected of having an eating disorder are urged to ensure that they receive needed care and rehabilitation. For some patients, medical treatment may be long term.

Eating disorders generally require a multi-disciplinary approach for rehabilitation that often includes:

  • Nutritional counseling. Regular consultation with a nutritionist (licensed nutrition specialist) or registered dietitian is important for patients with eating disorders. Nutrition experts may help patients gain a fundamental understanding of adequate nutrition including the importance of a healthy, well-balanced diet. These specialists also conduct dietary counseling, which can help patients change the nature of their eating behavior.

    In the case of anorexia nervosa, a nutritionist may initially set the patient on an eating plan for gradual weight gain. This is done to prevent any harm to the body, especially the heart, from a rapid increase in weight. Typically, patients might be expected to gain 2–3 pounds a week for patients at an inpatient facility and 0.5–1 pound a week for outpatients. In the case of bulimia and binge eating disorder, a nutritionist may assist in establishing a pattern of regular, non-binge meals.

  • Psychotherapy (e.g., cognitive behavioral therapy [CBT], family therapy). These types of therapy will address and help treat psychological disturbances including distortion of body image, low self-esteem and interpersonal conflicts associated with eating disorders.

  • Drug therapy (psychotropic medications, such as antidepressants). Antidepressants, such as the selective serotonin reuptake inhibitors (SSRIs), have been found helpful in treating eating disorders that co-exist with other types of emotional disorders, especially depression and anxiety disorders. Psychotropic medications may also help prevent relapse of eating disorders. Patients should be aware that a physician may need to adjust the dosage or change medications to achieve the best results with minimal side effects. In addition, the U.S. Food and Drug Administration has advised that antidepressants may increase the risk of suicidal thinking in some patients, especially adolescents, and all people being treated with them should be monitored closely for unusual changes in behavior.

    Since psychotherapy (e.g., CBT) appears more effective than medication for anorexia nervosa, use of medication in people with anorexia nervosa is usually offered as an adjunctive treatment to, and not a replacement for, psychotherapy. Medication treatment may pose additional risks among this population because of their low body weight, irregular heartbeat and electrolyte imbalance.

Patients with eating disorders are urged to have regular check-ups with their physician to monitor their overall health and treat any complications, such as cardiac arrhythmia (irregular heartbeat). Some patients with severe anorexia may experience diet-related complications as they gain weight and their metabolism shifts. This is known as refeeding syndrome, and it may involve electrolyte problems. These patients are usually closely monitored for electrolyte levels.

Sometimes, residential care that involves the patient remaining in a facility that specializes in treating eating disorders may be necessary, especially in the case of chronic relapses or when patients have not been able to reach a significant degree of medical and psychological stability from their initial treatment plans.

Patients with dental problems (e.g., tooth and gum decay) resulting from eating disorders may be referred to the care of a dentist (dental health specialist) for treatment. People with eating disorders may also benefit greatly from participating in support groups to prevent relapse as well as help cope with their condition. Physicians and mental health professionals can provide patients with information regarding support groups for people with eating disorders.

Prevention methods for eating disorders

Although eating disorders cannot always be prevented, they can be more effectively managed by taking steps that can reduce chances of a relapse including:

  • Attending regular follow-up consultations with a primary care physician, psychiatrist,psychotherapist and nutritionist to monitor the eating disorder
  • Eating healthy, well-balanced meals
  • Following a regular schedule of meals
  • Ceasing to eat once hunger is satiated, instead of when uncomfortably full
  • Taking vitamin and mineral supplements
  • Exercising regularly, as recommended by the physician
  • Getting proper rest and sleep
  • Engaging in activities that boost self-esteem, such as learning a new skill or hobby or joining a local social group
  • Setting realistic expectations regarding body and weight (for example, not accepting what some of the media portray about ideal body image)

In addition, family members and close peers of people with eating disorders can be a source of help and support by encouraging open communication and healthy eating and dieting habits.

Questions for your doctor on eating disorders

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions regarding eating disorders:

  1. What is your experience and how long have you been treating eating disorders?
  2. How will you determine if I have an eating disorder?
  3. What type of eating disorder do I have?
  4. What causes or triggers eating disorders?
  5. Can I die from my eating disorder?
  6. How will you treat my eating disorder?
  7. How long will the treatment process take?
  8. Will I need to take medications to treat my eating disorder?
  9. Should I receive therapy? What type of therapy would be best for me?
  10. I have a family member or friend with an eating disorder. What are the best ways to help her/him?
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