This essay will focus on the biological, cognitive and social factors that influence the eating disorder: bulimia nervosa. Individuals with bulimia are afraid of weight gain, and they will indulge in binge eating and then using compensatory methods to prevent weight gain, such as induced vomiting, excessive exercise and use of laxatives. Symptoms of bulimia include swollen salivary glands, due to repeated vomiting, stomach and intestinal problems, feelings of guilt after binge eating, as well as negative distorted image about their body weight.
The biological factors that I will be focusing on is evolutionary origins, genetic predisposition and effects of neurotransmitter.
Frisch et al suggested that eating disorders have evolutionary origins. During times of poor environment, where pregnancy would be difficult and offspring would have little chance of survival, it would have been adaptive for women to delay their pregnancy until a more appropriate time. Because low body fats results in termination of ovulation and menstruation, extreme dietary behaviours will eventually lead to the loss of fertility and the suppression of reproduction. Thus, preferences for thinner bodies would have been ideal for women who wanted to delay their pregnancy. However, an obvious weakness of this theory is that it excludes males, and it does not explain the eating behaviours in women that are not living in poor economic environments.
Genetic researchers argue that genetic predisposition may have influenced some people to be more "bulimic" than others. Kendler et al studied 2000 female twins in which at least one pair had been diagnosed with bulimia nervosa. He found that the concordance rate (which is the inheritance of two related individuals) to be consistently higher in monozygotic twins than dizygotic twins. Concordance rate was 23% in MZ twins compared to 9% in DZ twins, which suggests that genetics may have predispose some to develop eating disorders than others. The sample size was also very large, so it can be generalizable. However, concordance rate is not 100%, which means that genetics are not entirely to blame, but that other factors may have influenced eating disorder as well.
Another biological explanation is the role of neurotransmitters. Scientists have found low levels of serotonin in the brain of patients with eating disorders. Evidence of this is the study of Smith et al, who wanted to investigate the role of serotonin in patients with bulimia nervosa. Patients who recovered from bulimia nervosa were given a drug that reduced their serotonin levels. Smith closely monitored changes in behaviour after that. He found that patients reported an increase in negative thoughts about their body when their serotonin levels dropped. He concluded that low levels of serotonin may cause bulimia. Support for this theory also comes from an effective treatment for bulimia. Antidepressant drugs that increase serotonin levels can lead to dramatic reductions in the frequency of binge eating, according to Sterling and Hellewell. However, abnormal levels of neurotransmitters may not cause eating disorders, but may be the case that eating disorders cause changes in neurotransmitter - the direction of cause and effect is uncertain. The human body is very complex, and so we cannot simply attribute our behaviour to neurotransmitters.
After identifying the biological factors that could influence bulimia, we are still left without a clear understanding of how eating disorders may develop. The evolutionary theory seems vague and inapplicable in our society now, genetic predisposition is not 100%, and the direction of cause in neurotransmitter is uncertain.
Perhaps the cognitive levels of analysis may suggest a more clear understanding, as it is more related to how we develop eating disorders in the first place. Bruch suggested the body image distortion hypothesis, where many eating disorder patients suffer from the illusion that they are fat even when they are within the normal BMI range, and they tend to over-estimate their body size.
Zellner et al investigated women's assessments of their own body size. Female participants were given a questionnaire to see if they have a distorted image of their body. Females with high scores have a distorted image about their body, and females with low scores do not have a distorted image about their body. High scorers and low scorers were then assessed on their own body size, using line drawings of figures that ranged from thin to obese. The researchers then told the participants to choose a body that best resembled their own. They found that female participants with high scores tend to over-estimate their own body size and chose a larger body compared to female participants with low scores. This supports the body image distortion hypothesis, and it may be the case that many of the patients who suffer from eating disorder have a distorted image of their own body, and thus turn to extreme dietary behaviours to improve this. A weakness of this study is that it did not prove that patients with eating disorders have distorted image of their body, as the participants in this study did not suffer from eating disorder. It also excluded males, and therefore this study lacked population validity. Questionnaires are also an unreliable source of information, as participants usually don't know what to think and their answers may be "guesses". Those who scored low in the questionnaire may be too embarrassed to admit that they think negatively of their body, and there is the question of socially desirability bias in the questionnaire.
The cognitive explanation that people with eating disorders suffer from cognitive distortions is more descriptive than explanatory, as it does not explain how these distortions arise in the first place. It could also be the case that patients with eating disorder have distorted cognitions, rather than vice versa, and so it is difficult to establish cause and effect.
However, to derive oneself to think that their bodies are not ideal would mean that they must've been influenced in some way by social or cultural factors. Over the past 50 years, the ideal body shape for woman has changed in Western society, with more progression towards increasing thinness. The social learning theory states that people learn through observation and imitation of role models. As models start becoming increasingly thinner, this puts pressure on the people in society, who wants to imitate this rewarded behaviour by striving to be slim.
Bemis suggest that eating disorders arise from attempts by young woman to conform to a stereotypical and unrealistic body shape shown in magazines, televisions and advertisements. Many young woman look to the media for information about what is desirable, and if thinness appears to be highly valued than they would want to be thin as well.
Baguma et al carried out an experiment to see whether different societies and cultures will influence our body shape. He asked British and Uganda students to examine a set of nude bodies, ranging from very thin to very obese, and asked them to choose the body that they would want. He found that whereas British students chose very thin bodies, Uganda students chose very obese bodies. This is because in Western cultures, being thin is beautiful, but in Uganda being fat is beautiful. This shows that social and cultural factors influence how we think, which might explain why the Western society has such a high rate of people with eating disorders.
Support for this theory also comes from Lee, Hsu and Wing, who noted that bulimia and anorexia was non-existent among the Chinese people in Hong Kong. This can be largely explained in terms of sociocultural differences. Chinese people are usually slim, and do not share the Western fear of fatness. The Chinese regard thinness as a sign of ill-health and misfortune rather than the Western view of self-discipline. Obesity is seen as a sign of weak control, whereas Chinese people see it as a sign of health and prosperity.
The sociocultural approach seems much more clear, and that it is the society that has affected many individuals to develop eating disorders in attempt to look like models in adverts and feel beautiful about themselves. This is seen most in the Western society, where eating disorders are much more common. In societies like Hong Kong and Uganda, there is less pressure to be thin and therefore eating disorders are rare and almost non-existent.
It may also be the interaction of biological, cognitive and sociocultural factors that causes eating disorders. For example, it could be that genetic predisposition drives someone to think negatively about their body, and additional exposure to the environment and society's wants may have influenced someone to undertake binge eating and extreme dietary behaviours in order to improve their self-esteem and confidence.
The biological factors that I will be focusing on is evolutionary origins, genetic predisposition and effects of neurotransmitter.
Frisch et al suggested that eating disorders have evolutionary origins. During times of poor environment, where pregnancy would be difficult and offspring would have little chance of survival, it would have been adaptive for women to delay their pregnancy until a more appropriate time. Because low body fats results in termination of ovulation and menstruation, extreme dietary behaviours will eventually lead to the loss of fertility and the suppression of reproduction. Thus, preferences for thinner bodies would have been ideal for women who wanted to delay their pregnancy. However, an obvious weakness of this theory is that it excludes males, and it does not explain the eating behaviours in women that are not living in poor economic environments.
Genetic researchers argue that genetic predisposition may have influenced some people to be more "bulimic" than others. Kendler et al studied 2000 female twins in which at least one pair had been diagnosed with bulimia nervosa. He found that the concordance rate (which is the inheritance of two related individuals) to be consistently higher in monozygotic twins than dizygotic twins. Concordance rate was 23% in MZ twins compared to 9% in DZ twins, which suggests that genetics may have predispose some to develop eating disorders than others. The sample size was also very large, so it can be generalizable. However, concordance rate is not 100%, which means that genetics are not entirely to blame, but that other factors may have influenced eating disorder as well.
Another biological explanation is the role of neurotransmitters. Scientists have found low levels of serotonin in the brain of patients with eating disorders. Evidence of this is the study of Smith et al, who wanted to investigate the role of serotonin in patients with bulimia nervosa. Patients who recovered from bulimia nervosa were given a drug that reduced their serotonin levels. Smith closely monitored changes in behaviour after that. He found that patients reported an increase in negative thoughts about their body when their serotonin levels dropped. He concluded that low levels of serotonin may cause bulimia. Support for this theory also comes from an effective treatment for bulimia. Antidepressant drugs that increase serotonin levels can lead to dramatic reductions in the frequency of binge eating, according to Sterling and Hellewell. However, abnormal levels of neurotransmitters may not cause eating disorders, but may be the case that eating disorders cause changes in neurotransmitter - the direction of cause and effect is uncertain. The human body is very complex, and so we cannot simply attribute our behaviour to neurotransmitters.
After identifying the biological factors that could influence bulimia, we are still left without a clear understanding of how eating disorders may develop. The evolutionary theory seems vague and inapplicable in our society now, genetic predisposition is not 100%, and the direction of cause in neurotransmitter is uncertain.
Perhaps the cognitive levels of analysis may suggest a more clear understanding, as it is more related to how we develop eating disorders in the first place. Bruch suggested the body image distortion hypothesis, where many eating disorder patients suffer from the illusion that they are fat even when they are within the normal BMI range, and they tend to over-estimate their body size.
Zellner et al investigated women's assessments of their own body size. Female participants were given a questionnaire to see if they have a distorted image of their body. Females with high scores have a distorted image about their body, and females with low scores do not have a distorted image about their body. High scorers and low scorers were then assessed on their own body size, using line drawings of figures that ranged from thin to obese. The researchers then told the participants to choose a body that best resembled their own. They found that female participants with high scores tend to over-estimate their own body size and chose a larger body compared to female participants with low scores. This supports the body image distortion hypothesis, and it may be the case that many of the patients who suffer from eating disorder have a distorted image of their own body, and thus turn to extreme dietary behaviours to improve this. A weakness of this study is that it did not prove that patients with eating disorders have distorted image of their body, as the participants in this study did not suffer from eating disorder. It also excluded males, and therefore this study lacked population validity. Questionnaires are also an unreliable source of information, as participants usually don't know what to think and their answers may be "guesses". Those who scored low in the questionnaire may be too embarrassed to admit that they think negatively of their body, and there is the question of socially desirability bias in the questionnaire.
The cognitive explanation that people with eating disorders suffer from cognitive distortions is more descriptive than explanatory, as it does not explain how these distortions arise in the first place. It could also be the case that patients with eating disorder have distorted cognitions, rather than vice versa, and so it is difficult to establish cause and effect.
However, to derive oneself to think that their bodies are not ideal would mean that they must've been influenced in some way by social or cultural factors. Over the past 50 years, the ideal body shape for woman has changed in Western society, with more progression towards increasing thinness. The social learning theory states that people learn through observation and imitation of role models. As models start becoming increasingly thinner, this puts pressure on the people in society, who wants to imitate this rewarded behaviour by striving to be slim.
Orgen looked for evidence that the ideal shape for woman has become slimmer. The physical features of female fashion models from 1967-1987 were analysed. They found that over the 20 year period, models became taller, with a decrease in hip and bust measurements relative to waist size. Orgen concluded that the ideal female shape had become more androgynous and more slim.
Bemis suggest that eating disorders arise from attempts by young woman to conform to a stereotypical and unrealistic body shape shown in magazines, televisions and advertisements. Many young woman look to the media for information about what is desirable, and if thinness appears to be highly valued than they would want to be thin as well.
Baguma et al carried out an experiment to see whether different societies and cultures will influence our body shape. He asked British and Uganda students to examine a set of nude bodies, ranging from very thin to very obese, and asked them to choose the body that they would want. He found that whereas British students chose very thin bodies, Uganda students chose very obese bodies. This is because in Western cultures, being thin is beautiful, but in Uganda being fat is beautiful. This shows that social and cultural factors influence how we think, which might explain why the Western society has such a high rate of people with eating disorders.
Support for this theory also comes from Lee, Hsu and Wing, who noted that bulimia and anorexia was non-existent among the Chinese people in Hong Kong. This can be largely explained in terms of sociocultural differences. Chinese people are usually slim, and do not share the Western fear of fatness. The Chinese regard thinness as a sign of ill-health and misfortune rather than the Western view of self-discipline. Obesity is seen as a sign of weak control, whereas Chinese people see it as a sign of health and prosperity.
The sociocultural approach seems much more clear, and that it is the society that has affected many individuals to develop eating disorders in attempt to look like models in adverts and feel beautiful about themselves. This is seen most in the Western society, where eating disorders are much more common. In societies like Hong Kong and Uganda, there is less pressure to be thin and therefore eating disorders are rare and almost non-existent.
It may also be the interaction of biological, cognitive and sociocultural factors that causes eating disorders. For example, it could be that genetic predisposition drives someone to think negatively about their body, and additional exposure to the environment and society's wants may have influenced someone to undertake binge eating and extreme dietary behaviours in order to improve their self-esteem and confidence.
This is a huge life saver!! Thankyou:)
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