eating behaviour - Biological explanations

Question 1

Neural - Family studies - Chaput et al (2014)

Answer 1

Concordance rate (CR) for first-degree relatives are around 20-50% which indicates a moderate rather than substantial degree of heritability

Question 2

Neural - twin studies - Cassandra Nan et al (2012)

Answer 2

meta-analysis of 12 twin studies involving over 8,000 MZ & nearly 10,000 DZ twins. CRs ranged from 61 – 80% which demonstrates a very substantial genetic component to obesity.

Question 3

Neural - Polygenic determination - Locke et al (2015)

Answer 3

studied the genomes of 300,000+ people & identified 97 genes associated with variations in BMI. Action of genes on obesity is polygenic
There is no single genetic cause of obesity, many genes are involved – the 97 genes account for only 2.7% of BMI variation

Question 4

Neurotransmitters

Answer 4

Disruptions in levels of NT cause obesity

Question 5

Serotonin

Answer 5

low S-NT = obesity ​
Metabolite 5-HIAA used to determine levels of S-NT which inhibits VMH – satiety ​
Dysfunction may be due to stress/ mood disorders = energy dense cravings

Question 6

Ohia

Answer 6

serotonin receptor 2c = not in ‘knockout mice’ who overeat and are obese.

Question 7

Dopamine

Answer 7

Dysfunctional levels = obesity​

Normal levels stimulate HYP / Hippocampus / amygdala - pleasure derived from eating ​

Question 8

Wang

Answer 8

low dopamine D2 receptors in the striatum mean no reward from eating – eating for pleasure.

Question 9

AO3

Answer 9

S - Plausible
- Supporting research - Dopamine
- practical application
W - Contradictory evidence
- Diathesis