Discuss The Biological Explanations Of Obesity Essay

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Discuss the biological explanations of obesity Obesity is defined as a body mass index of 30 kg/m2. In 2008, in Britain 24% of people were obese and in the USA, obesity is the second biggest cause of preventable death, linked to cardiovascular disease, diabetes to name a few. The biological explanations can be split into Genetic explanations, neural/hormonal explanations and evolutionary explanations. There are a number of genetic conditions (such as Prader-Willi syndrome) where obesity is a classic symptom, suggesting that there is a genetic link to obesity. Wardle et al analysed 5000 twins aged 8-11 years and compared them in terms of BMI and waist circumference. They found a heritability figure of 77% with a relatively small environmental factor, half of which was due to shared environmental effects and the other half due to non shared effects. This study clearly shows a genetic link in obesity, as it is a twin study the genetic factor can be even more clearly deduced from these results. Frayling et al researched the fat mass and obesity gene in 2007 and found that people carrying two copies of this gene had a 70% increased risk of obesity ; people with one copy of the gene had a 30% increased risk, further supporting the genetic explanation of obesity. Price et al found further evidence for a link between the FTO gene and obesity in 2008 when they found a clear association between the FTO gene and obesity in a study of 600 extremely obese women with normal controls and with non-obese sisters. The large sample size used here means the study is far safer to generalize than a smaller scale study and the fact that the women all had non-obese sisters lessens the possibility of there being underlying environmental factors affecting the results. However, Wardle et al argued that the obesity epidemic is clearly due to environmental factors as levels of obesity are
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