Biological Explanations of Anorexia Nervosa

1. Biological Explanations of Anorexia Nervosa

2. Evolutionary Explanations • The reproductive suppression hypothesis Surbey (1987) adolescent girls desire to control their weight. Due to an evolutionary adaption in which ancestral girls delayed the onset of sexual maturation in response to a chance of poor reproductive success. The ability to delay reproduction is adaptive It enables a female to avoid giving birth at a time when conditions are not good for a babies survival.

3. Evolutionary Explanations • The reproductive suppression hypothesis This hypothesis is based on the observation that in a number of species puberty is delayed when they are subjected to stress or poor physical conditions Anorexia is the ‘disordered variant’ of the adaptive ability of females to alter the timings of reproduction when they are unable to cope with the responsibilities of womanhood

4. Evolutionary Explanations • The ‘adapted to flee’ hypothesis (AFFH) • Guisinger (2003) food restriction, hyperactivity, denial of starvation are similar to adaptive mechanisms that once caused migration due to local famine conditions.

5. Evolutionary Explanations • The ‘adapted to flee’ hypothesis (AFFH) • Normally when a person begins to lose weight, psychological mechanisms conserve energy and increase desire for food. These help survival. • However, years ago, when extreme weight loss was due to depletion of local resources, this natural instinct was turned off so that they can increase their chance of survival by migrating to a better environment.

6. Evolutionary Explanations • The ‘adapted to flee’ hypothesis (AFFH) • Food restriction is common in many species when feeding competes with migration and breeding. • Hyperactivity typically found in anorexics may be a form of ‘migratory restlessness’. • Species increase their activity when there is food shortage prior to migration

7. Evolutionary Explanations • The ‘adapted to flee’ hypothesis (AFFH) In the EEA (environment) the starving foragers who tricked themselves about their physical condition would have been more confident about moving on to a more favorable environment and would be more likely to survive. FOR MODERN DAY INDIVIDUALS, WHO ARE GENETICALLY VULNERABLE TO ANOREXIA,LOOSING TOO MUCH WEIGHT MAY TRIGGER ANCESTRAL MECHANISMS

8. Evolutionary Explanations • The ‘adapted to flee’ hypothesis (AFFH) • In the Middle Ages ‘holy anorexia’ was widespread among women.

9. Evolutionary Explanations