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Outline and evaluate the biological explanations of eating disorders

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Outline and evaluate the biological explanations of eating disorders? Introduction: A diet can turn into an eating disorder when BMI is below 15, but it is also generally accompanied by a distorted body image, an abnormal relationship with food, a morbid fear of gaining weight, cessation of periods (3 months) and denial that there is a problem Eating disorders may be associated with chemical imbalances in the brain; similar to OCD, depression. Low levels of serotonin have been especially found to be associated with binge eating. "Set Weight or Point" Theory: The set-point theory argues that an individual's metabolism (metabolic hormones and fat cell enzymes.) will adjust homeostatically to maintain a weight at which the body is comfortable. Dual-centre theory of feeding considers the two parts of the hypothalamus that are involved in our eating behaviour (negative feedback); the ventromedial hypothalamus (VMH) 'Satiety Centre' and the Lateral hypothalamus (LH) 'Feeding Centre'. VMH inhibits eating when we're full and responds to an increase in Blood Glucose Levels (BGL) ...read more.


As it was a laboratory experiment it was highly controlled which is good because other variables were controlled but it does lack ecological validity. However, other evidence does support Cumming's findings for example ghrelin injections result in increased food intake in animals and even real-life evidence gastric bands used to treat obesity, reduce ghrelin secretion. Although many studies have showed biochemical changes in individuals with eating disorders, it's difficult to decide whether these changes are the cause or the consequence of the eating disorder e.g. starvation may eventually cause an imbalance in biochemical functioning. Genetic origin: Eating disorders especially AN has been found to be an increased risk in the 1st-degree relatives of AN sufferer. (Holland et al. 1988). Twin studies carried out on identical twins and non-identical twins, have shown a 55% concordance rate in identical twins for anorexia nervosa, whereas only a 7% concordance rate in non-identical twins. This suggests a possible genetic factor. However, identical twins have 100% same genes, so why is there still 45% who were discordant. ...read more.


Also the sample of twins used was very small, so it was not an accurate representation of the population and cannot be generalised without limitations. Anorexia and bulimia nervosa are most common in white people in western societies. However, it is difficult to distinguish the influence of genetic factors and social/cultural pressures. A sudden increase in eating disorders about young women was noticed in a study in Fiji since the arrival of TV, (Fearn, 1999). This suggests a strong social and cultural component as TV seems to have influenced and pressurised these young women. Conclusion: A significant factor in the biological explanation of eating disorders is that it ignores the underlying cognitive problems and depression behind these disorders. The distorted image that more often than not accompanies eating disorders has not been explained by the biological explanation. The cause & progression of any eating disorder is unlikely to be singular, but more likely a combination of factors including: Biological, Psychological, Environmental and Socio-cultural. For example the diathesis model which believes that there must be genetic predisposition as well as an environmental trigger which cause a disorder. ?? ?? ?? ?? ...read more.

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