Eating disorder is a condition wherein an individual’s eating behavior of eating or not eating is influenced by a psychological impulse, instead of a physiological need. Individuals with eating disorders generally choose to ignore the signals their bodies send out that nourishment is needed for maintenance or that enough food has already been consumed. One general feature commonly observed in an individual with an eating disorder is abnormal weight, which may be either above or below the normal weight.
Normal weight has been defined by the World Health Organization (WHO) as having a body mass index (BMI) of 18. 5 to 24. 9 kg/m2 (Deurenberg and Yap, 1999; Weisell, 2002). BMI is the ratio of an individual’s weight in kilograms (kg) to his heights in meters squared (m2). An individual with a BMI of 25 to 29 kg/m2 is classified as overweight, those with BMI greater than or equal to 30 kg/m2 are categorized as moderately obese, and people with BMI of 40 kg/m2 and above are identified as morbidly obese.
Obesity was earlier considered as an imbalance between energy intake and energy expenditure. Today, obesity is regarded as a disease that is strongly influenced by genetic, physiologic and behavioral factors (Jequier and Tappy, 1999). The global estimate of overweight people is currently 1. 2 billion, of which at least 300 million are classified as obese. Obesity has been identified as a preventable health risk, but unfortunately, the mortality rate of this disease is still high, contributing to approximately 300,000 deaths each year in the United States alone.
Since the cases of overweight and obesity are continually increasing without any preference to economic status of a country, health governing bodies have put in a significant effort to promote awareness of this disease and intervention programs that would teach the public of the risks of being overweight and/or obese. A major factor that influences such excessive weight gain is the poor lifestyle choices individuals make, in terms of their eating, exercising and physical activities.
Binge eating is another eating disorder that is characterized by consuming huge amounts of food in order to achieve the strong feeling of being full. This disorder is generally involved with eating bouts even when an individual is not hungry. Anorexia nervosa is an eating disorder that is recognized in two forms- the restricting type and the binge-eating/purging types (APA, 1994). The restricting type of anorexia nervosa involves the absolute inhibition of food consumption and does not accompany any purging or binge-eating actions.
The binge-eating type of anorexia nervosa is commonly characterized by cycles of binge-eating and purging. The classic symptom of anorexia nervosa is subjecting one’s self to a starvation condition, with the main goal of preventing or avoiding gaining weight or sensing that any fat is deposited in the body. The psychological angle with anorexia nervosa is that the individual perceives himself as overweight yet actually, their weight is already below normal. The extreme condition of anorexia nervosa usually involves death due to severe malnutrition.
Bulimia nervosa is an eating disorder that is characterized by cycles of binge eating, purging and the employment of laxatives to remove any food that has been consumed (APA, 1994). Bulimia nervosa may be differentiated from anorexia nervosa through the feature that the individuals afflicted with this eating disorder typically have normal or above-average weights. In addition, individuals with anorexia nervosa can strongly inhibit their food intake, while individuals with bulimia nervosa find difficulty in avoiding food consumption.
Bulimic individuals commonly carry a psychological feeling of guilt and shame of eating so much food, hence they try to appease themselves of their eating faults through purging and chemical elimination of the food they ate through the use of laxatives. They consider such activities as remedies or cleansing rituals so that they can immediately purify themselves of the disgrace they made from eating huge amounts of food. To date, the exact cause of bulimia remains unknown, yet there are theories that this eating disorder is strongly associated to depression and anxiety, however, a precise correlation of this cause still has to be investigated.
Another theory involves the motivation of the bulimic individual to escape from reality, by treating for as a comfort instead of a source of energy and nutrition for their bodies. Childhood experiences may also possibly play a role in the cause of bulimia, because young children are often given different types of food in order to pacify them or to reward them for particular activities. Society may also play a role in bulimia, because the media strongly endorses that being thin is good, beautiful and acceptable.
It has been suggested that eating disorders may be physiologically influenced by serotonin and norepinephrine. It has also been suggested that anorexia is more frequently observed in females in the Western world (Suematsu, 1986). Several theories have been proposed to explain the mechanism behind hunger and eating in overweight and obese individuals. The internal-external theory of Schachter (1971) states that hunger is influenced by external signals such as time, as shown in their experiments involving manipulation of clock rates and counting the consumption of crackers by the subjects.
The research showed that faster ticking clocks that would reach meal times earlier would influence the subjects to eat earlier, while slower ticking close would influence subjects to eat later during the day. This theory strengthened the hypothesis that obese people tend to “feel” hungry based on the time of the day, and not based of the real sensation of hunger. The sensation of hungry in normal individuals is generally induced by internal signals such as an increased appetite or need to eat.
The boundary theory of hunger considers the cognitive influence of hunger and satiety, wherein an individual determines the amount of food he should take in, as their limit or boundary (Hermand and Polivy, 1984). During diet regimes, the amount of food an individual eats is a little less than the set amount or boundary and in turn, the body physiologically adapts to the available sources of energy. In overweight and obese individuals, the boundary of food intake is significantly higher than an individual of normal weight.
A third theory explaining the relation between excessive weight gain and eating is the set point theory, which is essentially based on the control of the hypothalamus on the body’s predetermined weight. Such set point of weight will be biologically maintained through the natural way, regardless of efforts to loss weight through diets and other weight loss regimens. A decreased intake of calories will not perturb the hypothalamus in its self-regulation of body weight. These theories are comparatively similar in terms of their goal of attempting to describe the mechanisms of obesity.
The theories all emphasized that obesity is not influenced by a single factor, such as plain and simple overeating. These theories actually describe external influences of factors that result in overeating. In the external-internal theory identifies the time of the day as the major factor that triggers hunger. For the boundary theory, the individual himself, most probably with the cerebellum as the major organ, determines the amount of food he will eat. As for the set point theory, the hypothalamus controls the individual’s body weight.
It is interesting to note that what the society has perceived as overweight is not really caused by a simple excessive hunger that stems from the need of the stomach to carry more food, but actually a more complex network involving the digestive system, the central nervous system and the immediate environment. Treatment for eating disorder often involves physical and psychological approaches. Psychotherapy serves as the main treatment for eating disorders, which often involves sessions with a therapist to discuss issues such as anxiety, depression, low self-esteem and body image concerns.
The therapist generally emphasizes the relationship of one’s thoughts and eating activities, as well as teaching the patient that food is a source of nourishment and not a source of comfort or escape. Antidepressants may be prescribed to an individual with an eating disorder, to regulate the emotions of the depressed individual. The physician will also need to regularly check the physical vital signs of the patient, in order to monitor whether the patient is gaining weight and to determine whether any other complications may be present in the individual.
Dieticians will design a well-balanced diet for an individual with an eating disorder, as well as educate the person of the nutritional value of every type of food that is consumed. The theories of hunger and eating disorders are based on the concept of primary motivation, which is mainly an interplay between psychology and the biological need to provide energy to the proper functioning of the human body. It is more complicated than the straightforward feeding mechanisms in other organisms because eating in the other species is singly influenced by the need to provide food for the normal physiology of the body.
In human beings that have a more complex brain system due to evolution, we have acquired the additional capability to feed our minds, and even our souls, so to speak figuratively. It is important to individuals to understand that the mind is a powerful organ that can influence the actions and activities of the rest of the body but it is also more important to know that such choices of eating the right amount of food, as well as the right type of food, is a conscious and voluntary choice, and the consequences should be seriously considered.