Psychological explanations for obesity

• What do psychological explanations for obesity include?

  • Restraint theory
  • Disinhibition
  • Boundary model
• Restraint Theory

  Herman & Polivy

  This is when the individual deliberately limits the amount of food they eat to lose weight but 80% of time it leads to overeating = obesity

  Limiting food intake leads to psychological stress, low moods and cravings.

  There are 2 factors to this theory

  • Cognitive control
  • Paradoxical outcome
• Cognitive control

  Restrained eaters set self imposed boundary on what they can or cant eat or how much.

  This caused them to constantly be thinking about food e.g. what's good or bad to eat

  This then leads to paradoxical outcome
• Paradoxical outcome

  Preoccupation with food means individual does not eat when their body signals hunger and eventually when they do eat, they don't stop when body signals its full
• Strength of restraint theory

  Empirical evidence

  Herman & Mack - questionnaire to identify pps level of restrained eating then gave them an ice cream taste test

  • Restrained eaters = more ice cream than controlled group of unrestrained eaters if they had been given milkshake before study

  Supports restraint theory as once they ate, their diet boundary was broken = paradoxical outcome
• Strength of restraint theory

  Practical application

  Weight management programs e.g. Weight Watchers promotes more healthy eating habits without extreme food restriction

  Explanation helps individual to avoid cognitive control that leads to overeating after breaking diet

  + Public health campaigns
• Limitation of of restraint theory

  Reductionist

  Overemphasise cognitive factors as being only factor of obesity

  Ignores social, biological, environmental factors that all contribute towards obesity
• Limitation of of restraint theory

  Cultural bias

  Theory only applies to western cultures

  Eating patterns may differ in other cultures e.g. reduced food availability

  Not generalisable to everyone
• Disinhibition 


  After period of restraint individual becomes tired of restricting themselves and starts eating as much as they can = overeating

  It starts by being influenced by other cues that are internal (e.g. low mood) or external (e.g. images of food).

  
  

  Once individual starts disinhibited eating they feel as if they are a failure so they might as well binge eat as they've broke the cognitive boundary
• Bond et al 


  Identified 3 types of disinhibition each with own impact on overeating

  1. Habitual disinhibition - overeat in response to life circumstances
  2. Emotional disinhibition - overeat in response to emotional states e.g. depression
  3. Situational disinhibition - overeat in response to specific environments e.g. social events
• Strength of disinhibition


  Empirical evidence

  Solid supporting research to show individuals who experience stress or negative emotions are more likely to overeat especially in high calorie food when they've previously attempted to control it

  • Heatherton and Baumeister - found disinhibition plays a role in overeating after self imposed restrictions e.g. stress

  Increases validity of theory
• Limitation of disinhibition

  Individual differences

  Fails to account for this, in how individuals respond to stress or cues. While some may overeat, some may have coping mechanisms e.g. exercising

  Suggests disinhibition alone cannot fully explain obesity in all individuals
• Strength of disinhibition

  Real world application

  Further knowledge in emotional eating.

  Recognising stress/emotions can lead to disinhibition can help ind

  CBT - teaches healthier ways to cope with emotions such as relaxation techniques. Helps individual control overeating, improves eating habits
• Boundary Model


  Herman & Polivy

  Proposed food intake is regulated along a continuum ranging from feeling hungry to feeling full (satiety)

  At one end = food intake is driven by biological processes when body energy is low = feel rise in hunger

  At other end = when we've had food = satiety meaning we stop eating

  In-between these two ends is a zone called - Biological Indifference
• Biological Indifference 


  Individual neither is hungry or full.

  This is where food intake is influenced by cultural/social factors or cues that are either internal or external
• Restrained eaters have larger zone of biological indifference, lower threshold for hunger and higher threshold for satiety.

  Meaning they get hungry more easily and will take longer to feel full

  Go over limit = 'what the hell' moment and will eat until satiety or beyond

  Unrestrained eater will eat until satiety
• Strength of boundary model

  Empirical evidence

  Stunkard et al - investigated interaction between internal cues (hunger) and external ( portion sizes)

  • Individuals were less sensitive to internal cues of satiety when larger food portions were provided

  Supports biological indifference as cues can dimmish effect of hunger and satiety
• Strength of boundary model

  Integration of cognitive and biological factors

  Model provides comprehensive explanation by looking at both factors

  Cognitive- psychological factors e.g. portion sizes influencing eating

  Biological - internal factors e.g. hunger and satiety signals

  Provides holistic approach
• Limitation of boundary model

  Oversimplification

  While it integrates both cognitive and biological factors. It oversimplifies complexity of eating behaviour

  Doesnt fully account for factors e.g. social influences which can play a significant role in obesity