Question 1

What is the role of the hypothalamus in eating behaviour?

Accepted Answer

The hypothalamus is a key brain region controlling hunger and satiety. The lateral hypothalamus (LH) acts as a 'feeding centre' – when stimulated, it triggers hunger; damage leads to aphagia (refusal to eat). The ventromedial hypothalamus (VMH) acts as a 'satiety centre' – when stimulated, it stops eating; damage leads to hyperphagia (overeating). However, this dual-centre model is oversimplified; other areas like the arcuate nucleus and paraventricular nucleus also play roles, and hormones like ghrelin and leptin modulate hypothalamic activity.

Question 2

How do evolutionary explanations account for food preferences?

Accepted Answer

Evolutionary explanations suggest our food preferences were shaped by natural selection to maximise survival. For example, a preference for sweet and fatty foods was adaptive because these are energy-dense and were scarce in ancestral environments. Neophobia (fear of new foods) protected against poisoning, while a preference for familiar foods ensured safe consumption. However, in modern environments with abundant high-calorie foods, these once-adaptive preferences contribute to obesity. Critics argue that evolutionary explanations are post-hoc and ignore cultural and individual differences.

Question 3

What is the difference between anorexia nervosa and bulimia nervosa?

Accepted Answer

Anorexia nervosa involves severe restriction of food intake, intense fear of weight gain, and a distorted body image, leading to significantly low body weight. Bulimia nervosa involves cycles of binge eating followed by compensatory behaviours (e.g., purging, excessive exercise) but body weight is often normal or slightly overweight. Both disorders share a preoccupation with weight and shape, but anorexia is characterised by restriction and low weight, while bulimia involves bingeing and purging. Anorexia has a higher mortality rate due to starvation-related complications.

Question 4

How does social learning theory explain eating behaviour?

Accepted Answer

Social learning theory (Bandura) suggests we learn eating behaviours by observing and imitating others, particularly role models like parents, peers, and celebrities. For example, children often adopt their parents' food preferences through modelling. Media also plays a role: exposure to thin models may influence dieting behaviour. Vicarious reinforcement (seeing others rewarded for certain eating habits) strengthens learning. However, this theory underestimates biological factors and individual agency; not everyone imitates observed behaviours.

Question 5

What is restraint theory and how does it relate to obesity?

Accepted Answer

Restraint theory (Herman & Mack, 1975) proposes that individuals who consciously restrict their food intake (restrained eaters) are more vulnerable to overeating when their cognitive control is disrupted (e.g., by stress or alcohol). This 'disinhibition' effect can lead to binge eating and weight gain. Restrained eaters often have a 'diet boundary' – a mental limit on calories – but once crossed, they may abandon control entirely (the 'what-the-hell' effect). This theory helps explain why dieting can paradoxically lead to obesity, though it has been criticised for overemphasising cognitive factors.

Question 6

Are eating disorders caused by genetics or environment?

Accepted Answer

Both genetics and environment contribute to eating disorders, making them biopsychosocial conditions. Twin studies show heritability estimates of 50-80% for anorexia nervosa, suggesting a strong genetic component (e.g., genes affecting serotonin and dopamine). However, environmental triggers like trauma, cultural pressure for thinness, and family dynamics are also crucial. For example, the 'anorexic family' model (Minuchin) highlights enmeshment and overprotectiveness. Most researchers now adopt a diathesis-stress model: genetic vulnerability combined with environmental stressors leads to disorder.

Eating behaviour

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