Eating disorder

A hormone secreted from the stomach and the amount released is proportional to stomach emptiness Cummings found that injections of ghrelin increase food intake and body weight in animals & humans. Gastric bands reduce ghrelin secretion in the stomach. Signals stopping the intake of food: meal size Cholecystokinin (CCK) Smith, Gibbs and Kulkosky found that inject of CCK in animals and humans reduce meal size. Also, animals with a genetic mutation eliminating the CCK system become obese.

This suggests that CCK signals satiety to the brain and contributes to the control of meal size. Signals controlling food intake: body weight Leptin This is a hormone released from fatty tissue Research says it’s an indicator of body weight to hypothalamic mechanisms controlling long term food intake It’s released from fat cells into bloodstream which travels to the hypothalamus and acts as a satiety signal.

Injections into the ‘ob’ mice stop them eating as much and their weight returns to normal (Carlson) Commentary Recent research suggests that eating behaviour is controlled by neural circuits that run throughout the brain. Sakurai suggests that the LH is not the brains ‘eating centre Gold suggested that lesions restricted to the VMH alone did not result in overeating. Can help to develop medical interventions and explains some individual differences. Reductionist, as feeding is a complex behaviour e.g. mood, culture and experience can effect feeding.

Luter suggests the body produces additional quantities of ghrelin in response to stress. Natural defense. Cummings research only had four male participants, hard to generalize to the population & women. Generalizing from humans to animals is difficult. Discuss two or more evolutionary explan ations of food preferences reference for high-fat foods Calories are essential to provide energy for the body to function; humans will have learnt this at an early age Preference for sweet foods This preference would encourage consumption of ripe fruit, advantageous as it provides important calories. Therefore, it would have been adaptive for humans to have evolved with an innate preference for sweetness

Preference for meat Without meat, its claimed humans wouldn’t have gained enough nutrition to become active and intelligent A diet containing meat is a far more efficient means of obtaining protein. Large occasional kills would mean that humans spend less time feeding themselves and the group aste aversion If we eat food that makes us sick, it would be an evolutionary advantage to avoid that food in the future. Garcia, Rusiniak and Brett made wolves sick with contaminated lamb’s meat, they would later leave sheep.

Suggests that they had learned to associate the poison with the sheep. Contributes to keeping the animal alive as it will affect the animal’s behaviour in the future. Commentary Evolutionary explanations can account for innate food preferences, increased level of world obesity. Capaldi found that all ages and other species prefer sweet food tastes than any other taste. Bell found that it’s not culturally learnt, as Eskimos preferred sweet foods. Gibson and Wardle found that children were likely to choose bananas and potatoes, rich in calories.

This suggests an evolved preference for calorie rich foods. Cultural differences can be seen as ‘fine tuning’ of evolved preferences. Reductionist as it ignores the influence of other factors such as cognitions, emotions and social factors. Determinist as they propose that eating behaviour is determined by previous environments, no free will.

When and how we eat is largely determined by our metabolism (the rate at which are body uses energy) and this is regulated by several physiological mechanisms: Set Point theory – biologically determined standard which our body weight is regulated. …

In an attempt to explain obesity and the failure of diets, many studies have shown that restrained eating may be the cause of overeating and weight gain. The Restrained theory was developed by Herman and Mack (1975) as a way …

Eating disorders are severe disturbances in eating behaviour characterized by preoccupation with weight concerns and unhealthy efforts to control weight (Weiten, McCann, 2007: 614). Eating disorder is a terrible illness that affects people in many ways. Eating disorders affect the …

Homeostasis is a neural mechanism that detects whether or not the body has enough nutrients and if it does not, how to restore the nutrients. Homeostasis works on a negative feedback loop; this is because the time taken to eat …

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