Biological Explanations For Obesity

Question 1

The expression of genetic influences varies with age:

Elks et al. (2012)

Answer 1

found that heritability estimates varied according to the age group of individuals. It was highest during childhood and then decreased during adulthood.

This is probably due to the lower gene expression during adulthood where individuals have adopted individual dietary and exercise habits decreasing the genetic input on their BMI etc

Question 2

Research support for the leptin-obesity relationship:
Montague et. al (1997)
Gibson et al. (2004)

Answer 2

some humans do not produce lepton and thus predisposes them to obesity.

M: reported on 2 severely obese cousins and found that both were found to have very low leptin levels

G: reported on a different child who suffered from severe obesity and after leptin injections, it had beneficial effects on appetite, metabolism and weight

Question 3

Advantages of biological explanations:

Answer 3

they offer explanations of obesity that are perceived as being out of the individual’s personal control and thus less stigmatising.
whereas psychological explanations blame the individual

the simplicity of it makes them more ‘attractive’ than complex psychological explanations which focus on several contributing factors

Question 4

Problems with the thrifty gene hypothesis:

Speakman (2008)

Answer 4

argues that if the thrifty gene explanation is correct, then the majority of human should have inherited these thrifty genes and if they cause obesity then majority of humans should be obese.

N: found that more than half of the worlds obese population live in 10 countries suggesting that it may be due to cultural factors rather than evolved adaptions.