Anorexia nervosa is a serious eating disorder involving self-starvation and extreme weight loss. The clinical definition requires that an individual drop down to 85 percent of normal weight. Individuals with anorexia experience an intense fear of weight gain, a distorted body image and the absence of menstruation (in females who have already had their first menstrual period, but who are not postmenopausal). Often individuals with anorexia nervosa fixate on a body part deemed “too fat” or believe they are fat, despite being extremely underweight. Anorexia has two forms: Binge-eating/purging type and Restricting type anorexia.

Anorexia athletica: A condition involving a combination of dieting, fasting and excessive exercise. The condition is often associated with anorexia nervosa.

Anorexia tardive: Anorexia that begins later in life. The term was first coined by researcher Peter Dally to indicate women who developed anorexia for the first time after the age of 25. The term has since been applied to anorexia that emerges in late life.

Athletic Triad: A combination of three interrelated illnesses that develop when an individual, most often a female athlete, goes to extremes in both dieting or exercise. These include:

--Disordered eating and excessive exercise that prevents the body from getting enough nutrition.

--Lack of menstruation (amenorrhea) caused by hormonal changes, low caloric intake, high energy demands and stress.

--Osteoporosis caused by lack of periods which deplete the body of necessary bone-building molecules.

Binge: An episode in which an individual binges or binge eats.

Bingeing/Binge eating: Eating an amount of food in a discrete period of time (i.e. 2 hours) that is definitely more than most people would eat in a similar period of time under the same circumstances. While bingeing, an individual may eat to the point of feeling uncomfortably full and may still continue to eat more.  Bingeing may be characterized by eating rapidly and/or a feeling of being “out of control” to stop, and sometimes “out of body.” Bingeing may be used to anesthetize strong or uncomfortable emotions, but later may lead to extreme guilt and sadness. For these reasons, bingeing is often done in secret. A binge refers to an episode of binge eating.

Binge-eating/purging anorexia: The most common form of anorexia. Individuals afflicted regularly binge eat and/or purge to control their weight. Some individuals actually do not binge eat, but regularly purge (e.g., vomit, use laxatives) after consuming even small amounts of food. The difference between binge/purge anorexia and bulimia is mainly weight. Anorexia is defined by weighing less then 85 percent of normal, while individuals with bulimia often weigh in as normal or overweight.

Binge eating disorder (BED): A condition in which individuals experience recurring episodes of uncontrolled eating, referred to as “binges” or “bingeing” or “binge eating.” More individuals have binge eating disorder than do anorexia and bulimia nervosa combined. During a binge, an individual eats to the point of feeling uncomfortably full and may still continue to eat more. Binges are characterized by a feeling of being “out of control” to stop, and sometimes “out of body.” Individuals with BED binge to anesthetize strong or uncomfortable emotions, but later feel extreme guilt and sadness over their loss of control during eating.

It is important to note that BED differs from bulimia nervosa, which also involves bingeing. BED does not involve purging behaviors (e.g., self-induced vomiting, use of laxatives) or extreme exercise to avoid weight gain.  Therefore most individuals with BED are overweight or obese. Many also suffer depression. But doctors are not sure if the symptoms cause BED or result from it.

Body dissatisfaction: The negative experiences, thoughts and feelings an individual has in the context of his or her body. In development terms, body image arises as a person experiences culture and environment and then develops perceptions, beliefs and feelings about how their body looks in relation to the bodies of others. Body dissatisfaction arises when that self-awareness about body becomes negative. Contributors to body dissatisfaction include being teased or criticized about weight or shape, trying to reach an impossible ideal of appearance and unhealthy eating habits such as starving, bingeing and purging that affect mood.

Body image: The mental picture an individual has of oneself, which gradually develops and constantly changes for each individual over time and through experience.

Body Dysmorphic Disorder: A mental disorder in which an individual has a disturbed body image. He or she is extremely critical of their physique or self image, even if there is no noticeable disfigurement. For example, an individual may fixate on a perceived flaw, i.e. a mole, freckle, scar or body part and react obsessively, either ruminating about it or trying desperately to change it.

Bulimia nervosa: An eating disorder that is characterized by a pattern of binge eating followed by purging behaviors. These include self-induced vomiting, done to control or prevent any weight gain resulting from binges. Purging can also include overexercise. The U.S. National Institute of Mental Health (NIMH), estimates that 1 to 4 percent of females suffer from bulimia during their lifetime. But since bulimia is often secreted, sometimes for decades, the number of reported cases is likely a gross underestimate. Bulimia nervosa has two forms: purging and nonpurging bulimia.

Chronic illness: Lasting a long period of time or marked by frequent recurrence. Chronic diseases such as alcoholism or diabetes are considered treatable but not curable. Eating disorders may be viewed as chronic illness, able to be treated and kept at bay, but not able to be “cured.”

Cognitive Behavioral Therapy: A traditional psychotherapy used for the treatment of eating disorders, mainly bulimia nervosa. Based on a model created by Aaron T. Beck to treat depression, therapy hinges on the premise that thoughts and emotions motivate actions and actions feed back to change thinking and feeling patterns. Therapy then works to change, simultaneously, behaviors that lead to eating disorders and the negative thoughts behind them.

Depression: Feelings of sadness, hopelessness or lack of meaning the individuals experience occasionally. Clinical depression is a mood disorder that involves persistent feelings of sadness, anger, irritability and/or lack of interest in once-cherished activities. Clinical depression may severely hamper an individual’s ability to enjoy life and increases risk for suicide.

Diabetes: A chronic disease characterized by problems with the body's ability to use sugar. Diabetes comes in two forms. Type I diabetes is an inherited condition in which an individual cannot produce insulin, a hormone that regulates blood sugar metabolism. Type II diabetes involves an inability of a person’s insulin to exert its normal physiological actions on the body. Eating disorders such as binge eating disorder, linked to obesity, increases an individual’s risk for type II diabetes.

Disordered eating: Individuals who exhibit disordered eating engage in many of the dieting, bingeing and purging behaviors that characterize eating disorders but not to the extreme degree that leads to a medical diagnosis. Sometimes individuals who have recovered from an eating disorder continue on with their disordered eating behaviors while staying well enough to avoid diagnosable eating disorders. These individuals have “subclinical disorders,” those that fall underneath the medical radar. In other cases, individuals engage in odd eating habits like chewing and spitting out food, eating only one meal a day during narrow time frames (e.g. only after 5 p.m.), or extreme portion control.

Eating disorders: These are conditions characterized by serious disturbances in eating behavior, such as extreme dieting or fasting, compulsive overeating (bingeing) and/or purging, including self-induced vomiting and overexercise. Eating disorders experts have laid out strict criteria for each of the three most common eating disorders: anorexia nervosa, bulimia nervosa and binge eating disorder. Individuals who do not fit the criteria but have serious eating disorders nonetheless, are diagnosed with “eating disorder not otherwise specified” (EDNOS).

Experts estimate that 10-15 percent of individuals with severe eating disorders die from either their illness or its complications. While most often eating disorders develop during adolescence and young adulthood, they can emerge at any age. Americans are now witnessing a hidden epidemic of eating disorders in adult women, with women in their 40’s and 50’s checking in for treatment at numbers triple and quadruple those of 15 years ago.

Eating disorders not otherwise specified (EDNOS): Disorders that involve serious abnormal eating behaviors but do not fit the set criteria for classic eating disorders such as anorexia and bulimia nervosa. For example, a woman who diets enough to become severely underweight (less than 85 percent of normal) but does not lose her menstrual periods would be diagnosed with EDNOS. These disorders are serious enough to call for medical intervention or therapy. Most eating disorders fall into this category.

Excessive exercise: See overexercise.

Gene: The string of molecular code that controls the appearance and display of a particular trait, i.e. eye color. Genes can also control behavioral traits such as anxiety or impulsiveness. Therefore geneticists hypothesize that genes or alterations in genetic code lie behind an individual’s predisposition to an eating disorder. Researchers have already discovered evidence to support this genetic hypothesis. Individuals with the “right” genetic makeup for an eating disorder may not acquire one. That is because environment also plays a role in inciting eating disorders.

Infantile anorexia: A rare eating disorder that affects infants and toddlers, characterized by food refusal and resulting delays in growth. The illness also involves a high degree of conflict between mother and child.

Interpersonal psychotherapy: This traditional psychotherapy works to change eating disorder behaviors by working mainly with the motivations behind the behaviors. A therapist explores what else is going on in an individual’s life, past and present, that might have precipitated illness. By uncovering and dealing with those hidden motivators, the eating disorder behaviors become less important and begin to drop off.

Nonpurging bulimia: A rare form of bulimia. Individuals do not engage in traditional purging methods (i.e. vomiting) to avoid weight gain. Instead, afflicted individuals follow episodes of binge eating by strict dieting, fasting and/or overexercise.

Obesity: A condition in which a person bears an excess of body fat and so impairs his or her physical health. The exact line between “overweight” and obese varies according to medical chart data but generally obesity is defined as 30 percent above normal weight. Obesity increases the risk for diabetes, heart disease and cancer as well as psychological problems including low self-esteem and depression.

Orthexia: A condition in which individuals abuse health foods by feeling excessively anxious about foods not deemed healthy. The individual will react obsessively about their food and feel out of control to stop their obsession. While those who eat macrobiotic diets and extreme vegans do not necessarily have orthexia, the level of food restriction in these two diets illustrates how orthexia displays itself.

Osteoporosis/Osteopenia: A disease characterized by low bone density that can lead to an increased risk of fractures. To test for osteoporosis, doctors perform a special kind of X-ray, called dual-energy x-ray densitometry. A score between -1 and -2.5 (1 to 2.5 standard deviations below the norm) means that an individual has osteopenia, the precursor to osteoporosis. A score lower than -2.5 indicates osteoporosis. Women with anorexia nervosa have a higher risk for osteoporosis.

Overexercise: Exercising excessively and compulsively in order to prevent weight gain or promote weight loss. Overexercise involves addictive properties in which an individual feels depressed or guilty if he or she misses even one workout and feels out of control to stop or cut back, even when sick, injured or exhausted. Individuals who overexercise regularly forego social events in order to perform their regimented workouts.

Pica: A rare eating disorder in which individuals crave and eat nonfood items such as dirt, paint chips and coffee grounds. The disease occurs more frequently in people with developmental disabilities such as autism and sometimes in pregnant women.

Purging: Any behavior meant to remove unwanted substances from the body. In the context of eating disorders, the “substance” is usually food and the behaviors are vomiting and use of laxatives or herbs that stimulate bowel movement. Some eating disorders experts consider excessive exercise as a purging behavior.

Purging bulimia: The more common form of bulimia. Individuals binge eat and also regularly engage in purging behaviors to control their weight. These include vomiting and use of laxatives or herbs that stimulate bowel movement.

Recovery: When experts refer to a patient who has undergone “recovery” from an eating disorder, they mean that the individual has stopped his or her eating-disordered symptoms, permanently. Patients can also recover partially, meaning that they have cut down or back upon the behaviors that led to their eating disorders. Again, the state of recovery is permanent or, at least, lasting for a long time.

Remission: Remission is a medical term in which a disease or condition has not fully gone away. Most often linked to cancer, the idea is that some aspect of the disease remains latent, even though symptoms may have ceased. Eating disorders expert David Herzog at Massachusetts General Hospital in Boston has made the argument that therapists should refer to patients who stop their eating-disordered symptoms for a short time, as “in remission” rather than as “recovered.”  The semantics arise from the high relapse rate of eating disorders patients within a year of treatment. See: rule of thirds.

Restricting type anorexia: A rarer form of anorexia. Individuals maintain their low weight mainly by dieting, fasting and/or overexercise (anorexia athletica).

Rule of thirds: Researchers estimate that roughly a third of women with eating disorders fully recover after therapy. Another third stay diagnosably ill throughout life, sometimes dying from their eating disorder or its complications. The final third partially recover, either engaging in less severe disordered eating /subclinical disorders or relapsing and recovering periodically throughout life. (Source: the D.B. Herzog et al. Journal of the American Academy of Child and Adolescent Psychiatry 38:829-837, 1999).

Rumination disorder: An eating disorder in which individuals repeatedly vomit, rechew and reswallow food or vomit, rechew and spit out food. The disorder is most common in infants or individuals with mental retardation.

Set point theory: The idea that every individual is born with a unique set of genes that control his or her body size and shape. When an individual tries to deviate too far from his or her set point, i.e. through dieting and exercise, the body will respond with a series of strong biochemical triggers to try and move an individual back to the set point. Radical dieting often leads to bingeing as the body tries to return to its genetic set point after losing too much weight or losing it too quickly.

Selective Serotonin Reuptake Inhibitors (SSRIS): A family of medications first used to treat depression, hence the moniker, “antidepressants.” In the realm of eating disorders, SSRIs such as Prozac have helped lesson the symptoms of bingeing in bulimia and binge eating disorder.

Subclinical disorders (see disordered eating): Eating problems that are not severe enough to qualify for medical diagnosis and therefore fall underneath the medical radar. Sometimes individuals who have recovered from an eating disorder continue on with their disordered eating behaviors while staying well enough to avoid diagnosable eating disorders. Others engage in unhealthy food and exercise rituals that never become serious enough to meet clinical criteria for an eating disorder.