Eating Behaviour

This section explores the topic of Eating Behaviour as part of the Psychology module Issues and Options in Psychology. These notes cover explanations for food preferences, the control of eating behaviour, explanations for anorexia nervosa and obesity, and factors influencing the success and failure of dieting.

Explanations for Food Preferences

Evolutionary Explanation

Neophobia: A fear of new foods, particularly common in children. Neophobia is thought to be adaptive, helping early humans avoid potentially toxic or harmful foods.

Taste Aversion: An aversive response to a food following an unpleasant experience, such as nausea. This response is highly adaptive as it helps individuals avoid harmful foods in the future. The "Garcia effect" demonstrates how a single instance of nausea can lead to a long-lasting aversion to a particular taste or food.

Role of Learning in Food Preferences

Social Influences: Parents, peers, and media can shape food preferences through modelling and reinforcement. Children may adopt food preferences observed in parents or friends.

Cultural Influences: Culture plays a significant role in shaping what foods are considered desirable. Cultural norms dictate acceptable foods, portion sizes, and meal times, influencing food preferences from a young age.

Conditioning: Positive reinforcement, such as praise for trying new foods, or associating certain foods with enjoyable experiences, can increase preferences for specific foods.

Neural and Hormonal Mechanisms in Eating Behaviour

Role of the Hypothalamus

The hypothalamus regulates hunger and satiety through two key areas

Lateral Hypothalamus (LH): Often referred to as the "hunger centre"; it triggers feelings of hunger when energy levels are low.

Ventromedial Hypothalamus (VMH): Known as the "satiety centre"; it signals fullness and reduces food intake when energy needs are met.

Hormones Influencing Hunger

Ghrelin: A hormone produced by the stomach that increases appetite. Ghrelin levels rise before meals and decrease after eating, signalling hunger to the brain.

Leptin: A hormone released from fat cells that signals the hypothalamus to suppress appetite. High levels of leptin are associated with reduced hunger, as it indicates that the body has sufficient energy stores.

Biological Explanations for Anorexia Nervosa

Genetic Explanation

Anorexia nervosa appears to have a genetic component, with family and twin studies showing higher prevalence in individuals with a family history. Some research suggests a genetic predisposition involving neurotransmitters like serotonin.

Neural Explanation

Serotonin Dysregulation: Serotonin imbalances are thought to contribute to anxiety and mood regulation issues in anorexia, potentially leading to the restrictive eating patterns seen in the disorder.

Dopamine: Altered dopamine functioning may impact reward processing, possibly causing those with anorexia to feel anxious or guilty about food rather than finding it rewarding.

Psychological Explanations for Anorexia Nervosa

Family Systems Theory

Enmeshment: Describes family environments where boundaries are unclear, and members are overly involved in each other's lives. This may limit individual autonomy, leading individuals to seek control through food.

Autonomy and Control: The desire for independence may lead some individuals, especially adolescents, to express control over their bodies through restrictive eating as a means of gaining autonomy from their families.

Social Learning Theory (SLT)

Modelling: Individuals may observe and imitate behaviours associated with thinness, especially in media or among peers. This modelling can lead to restrictive eating patterns.

Reinforcement: Positive reinforcement, such as compliments for weight loss, can encourage further restriction.

Media Influence: The portrayal of thin bodies as the ideal body type can contribute to the internalisation of thinness as desirable, potentially leading to anorexia.

Cognitive Theory

Distortions: Individuals with anorexia often have distorted views about their bodies, seeing themselves as overweight even when they are underweight.

Irrational Beliefs: Beliefs such as "I must be thin to be accepted" or "Eating will make me lose control" can drive restrictive eating and body image concerns.

Biological Explanations for Obesity

Genetic Explanation

Obesity has a strong genetic component, with genes influencing factors such as metabolism, appetite, and fat storage. Twin studies suggest that genetic factors account for a significant portion of BMI variability.

Neural Explanation:

Dopamine: Dopamine deficiencies may reduce the reward experienced from eating, leading some individuals to consume larger quantities to achieve satisfaction.

Leptin Resistance: In some obese individuals, leptin levels are high but ineffective in signalling satiety, possibly due to leptin resistance, which may contribute to overeating.

Psychological Explanations for Obesity

Restraint Theory

Dieting or consciously restricting food intake can paradoxically lead to overeating. This theory suggests that attempts to restrain eating can make individuals more preoccupied with food, increasing the likelihood of eventual binge eating.

Disinhibition

Disinhibition refers to a loss of restraint, where certain cues (e.g., emotions, presence of tempting foods) trigger overeating. This is common among restrained eaters, who may binge eat after minor dietary lapses.

Boundary Model

Proposed by Herman and Polivy, this model suggests that individuals have a “hunger boundary” and a “satiety boundary.” For restrained eaters, crossing these boundaries (e.g., by breaking a diet) can lead to a loss of control and excessive eating.

Success and Failure of Dieting

Factors Influencing Success

Realistic Goals: Setting attainable goals increases motivation and likelihood of long-term success.

Self-Monitoring: Keeping track of food intake and behaviours can improve diet adherence.

Social Support: Support from friends and family can help maintain motivation and accountability.

Factors Influencing Failure

Restrained Eating: Excessive restriction can lead to preoccupation with food and binge-eating episodes when the diet is broken.

Emotional Eating: Individuals may overeat in response to emotions (e.g., stress or sadness), leading to failure in dieting efforts.

Cognitive Dissonance: Dieters may experience conflict between their desire to lose weight and the desire to eat enjoyable foods. This dissonance can result in diet lapses.

Summary

The Eating Behaviour module explores the factors influencing food preferences, the biological and psychological mechanisms involved in conditions such as anorexia nervosa and obesity, and the factors that impact the success or failure of dieting. Evolutionary and cultural factors shape food preferences, while hormones like ghrelin and leptin play crucial roles in hunger regulation. Biological explanations suggest genetic and neural influences on anorexia and obesity, while psychological theories emphasise family dynamics, social influences, and cognitive distortions. Understanding these influences provides insight into both the causes of disordered eating and strategies for effective intervention.