Eating Behaviour Unit PSYA3 Miss Bird

Homework due  Essay question (January 2011) Discuss the role of one or more factors that influence attitudes to food. (4 marks A01 and 8 marks A02). Essay plan or essay answer

Biological explanations of eating behaviour AQA A Specification   Eating behaviour Factors influencing attitudes to food and eating behaviour. For example: cultural influences; psychological influences (mood); and social influences (health concerns/media). Explanations for the success and failure of dieting. Biological explanations of eating behaviour Neural mechanisms involved in controlling eating behaviour. Evolutionary explanations of food preference. Eating disorders In relation to either anorexia nervosa or bulimia nervosa: Psychological explanations. Biological explanations, including neural and evolutionary explanations.

Today’s lesson Why do people diet? What is dieting? Restraint Theory and the Boundary Model (Herman and Polivy, 1984). Key studies – Herman and Mack (1975), Wardle and Beales (1988). Evaluation of Restraint Theory and key studies. Application of IDA.

Starter: Pair activity What diets have you heard of? Why do people diet? What does dieting involve? Why might some people be more successful at dieting than others? You have 5 minutes.

Why do people diet? To lose weight and ‘improve’ appearance. Primary motivation = body dissatisfaction. A consequence of body dissatisfaction is the need to diet and lose weight in order to change your body size and shape.

So…What is dieting? Voluntary restriction of food intake in an attempt to encourage weight loss (a behavioural and cognitive intervention). Three basic forms of dieting associated with restriction of food intake: - Restrict the total amount of food eaten. Do not eat certain types of food. Avoid eating for long periods of time. The aim of losing weight then becomes the primary focus when choosing what foods to eat and how much.

Restrained eater (Dieter) Restraint Theory The boundary model (Herman and Polivy, 1984) Why dieting may lead to overeating Hunger Min. level Satiety Max. level Normal eater Hunger Diet boundary Satiety Restrained eater (Dieter)

Restraint Theory: Normal eater Food consumption is regulated by biological processes to keep food intake within a set range. Hunger keeps intake of food above a specific minimum level. Satiety (feeling of satisfaction/fullness) keeps intake of food below a specific maximum level. Your hunger and satiety levels are determined by your body weight set point (your biology). Within this set range, eating is regulated by social, environmental and psychological factors. Hunger Min. level Satiety Max. level Set range Normal eater

Restraint Theory: Restrained eater (dieter) Dieters tend to have a larger range between hunger and satiety levels than normal eaters as it takes them longer to feel hungry and more food to satisfy them. Dieters also have a self-imposed, desired intake of food – a cognitive dietary boundary (what they think they should eat and how much). If they exceed this diet boundary they continue to eat until they reach satiety (which is higher than that of a normal eater). This consequently leads to overeating. Hunger Cognitive diet boundary Satiety Restrained eater

Independent task Answer the 4 questions on the boundary model in your booklet. You have 5 minutes, then Q&A.

To summarise… Therefore, the boundary model (part of restraint theory) attempts to explain why diets may fail.

Factors that regulate eating/dieting The role of genetics Suggested that body weight can be influenced by genetic factors (e.g. inherited; ‘ob’ gene for obesity). Genes may influence factors such as appetite regulation, metabolic rate and the number of fat cells a person has.

Factors that regulate eating/dieting The role of social and environmental pressures Increases in portion sizes of meals can promote overeating. Exposure to the ‘ideal’ body size and weight in the media can influence food intake (SLT). Cognitive factors Dieters may impose a cognitively-determined diet boundary to control food intake (thoughts about foods).

Herman et al (2005) Factors that promote overeating in dieters: - Distress – e.g. extreme anxiety. Cravings – dieters more prone to experiencing them due to food restrictions. Pre-loading – portion of food given to people before they are allowed free access to other foods – should suppress appetite but can have the opposite effect in dieters i.e. overeating.

Herman and Mack (1975) Pre-load / taste test paradigm 45 female participants (dieters and non-dieters) were given a pre-load food, either high or low calorie (chocolate or crackers). Participants then told they were taking part in a taste preference test and were left alone to do the taste test in their own time. Observed how much of the food they ate. FINDINGS: The dieters ate more in the taste test if they had the high calorie preload (chocolate). CONCLUSION: Restrained eating can result in over-eating.

Independent task Read the supporting research by Wardle and Beales (1988). Outline the APFCC in your booklets. You have 10 minutes, then Q&A.

Evaluation Implications for obesity treatment Restraint theory suggests that food restriction can lead to overeating. However treatment for obesity often recommends restraint as a solution to excessive weight gain. Although obesity may not be caused by overeating (e.g. ‘ob’ gene), overeating may be a consequence of obesity if restraint is recommended as a treatment (Ogden, 1994). Therefore not an appropriate treatment for obesity if theory is correct.

Evaluation Restraint theory has limited relevance Restraint theory suggests a link between food restriction and overeating. Dieters, bulimics and anorexics report episodes of overeating. However, if trying not to eat results in overeating (according to restraint theory), then how do anorexics manage to starve themselves? Cannot explain restricting behaviour in anorexics (i.e. avoiding meals, carefully weighing and portioning food) as according to restraint theory, this should result in overeating and weight gain, not severe weight loss.

IDA (A02) In your booklets or on lined paper, identify any relevant IDA for today’s lesson content. You have 10 minutes in pairs.

IDA (A02) Methodology. Gender bias. Nature vs. Nurture. Determinism vs. free will. Reductionism. Approaches – biological, cognitive, learning.

Homework  Research and make notes on ‘The theory of ironic processes of mental control’ by Wegner (1994). There is space in your booklets for this information.