Success and failure of dieting A2

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Success and failure of dieting A2

  1. 1. 1
  2. 2. Starter O In pairs - list as many diets as you can? O Do you think diets are successful? O Think of as many reasons as you can as to why diets are or are not successful. 2
  3. 3. Dieting? O Usually involves trying to eat less than usual – placing a cognitive limit on food intake and attempting to eat up to a limit that is less than what a person would normally eat (less than our daily recommended allowance). Up to 70% of women diet at some point in their lives.
  4. 4. What makes a person decide to go on a diet? Write down 3 reasons on the mind map Why do people diet?
  5. 5. Three types of diets: O 1 : restricting the total amount of food eaten O 2: refraining from eating certain types of food O 3 : Avoiding eating for long periods of time
  6. 6. Dieting most often due to Body dissatisfaction But what factors contribute to body dissatisfaction? Ogden, 2007: 1. 2. 3. 4. 5. Media influence Family Ethnicity Social Class Peer groups & social learning 7
  7. 7. O How many females do you think will consciously reduce their food intake in their lifetime? O89% et al 1987 Kleges
  8. 8. Restrained Eaters O Restrained = restricted, holding back O A ‘restrained eater’ is someone who is trying to eat less (i.e. Dieting)
  9. 9. Restrained eating (dieting) O Research (laboratory studies) has shown that restrained eaters often overeat.
  10. 10. 1) Restraint Theory Herman & Mack (1975) O Attempting not to eat actually increases the probability of overeating (see next study) O Explained by the ‘Boundary Model’ O NOTE: RESTRAINED EATER = DIETER 11
  11. 11. Herman & Polivy’s BOUNDARY MODEL (1984) O We all have a biological/physiological boundary for food intake.
  12. 12. O But restrained eaters (dieters) have a cognitive boundary as well. O This is much less than the biological one.
  13. 13. Two potential boundaries for Physiologi intake food cal Cognitive O Set by the body weight set- point O The body’s fat stores act as a ‘body-weight set-point’. O Under normal circumstances mechanisms controlling food intake do not allow for much weight fluctuation. O Set by the individual O In restrained eaters this is less than the physiological boundary.
  14. 14. Food intake boundaries Unrestrained eater O Eats until satiety (fullness). O The physiological boundary determined by their body weight setpoint. Restrained eater O Eats until they reach their cognitive boundary (set by themselves).
  15. 15. O The problem is once the cognitive boundary has been crossed there is a disinhibition effect O = ‘What the hell’.
  16. 16. O This can result in the person carrying on eating and even crossing the biological boundary.
  17. 17. Early research O O O O Herman and Mack (1975) One of the earliest studies using the preload/test method. Participants = 45 female students told it was a study on taste experiences Independent design 3 conditions – 15 participants in each
  18. 18. 3 conditions O 1 = no preload O 2 = preload = one milkshake – asked to rate the taste quality O 3 = preload = two milkshakes –asked to rate the taste quality
  19. 19. O All 3 groups then given three tubs of ice cream of different flavours O Given 10 minutes to rate their taste qualities O Told they could eat as much of the ice cream as they wanted
  20. 20. O All participants were given a questionnaire to assess their degree of dietary restraint.
  21. 21. O Each of the 3 groups were divided into high restraint or low restraint depending on their answers given on the questionnaire.
  22. 22. O LOW RESTRAINT O This was AS EXPECTED GROUP O Ate less ice cream in the 2 milk shake condition than in the one or none group. O They feel fuller after the 2 milk shakes and can’t eat as much ice-cream.
  23. 23. Method O Given 3 different flavoured tubs of ice cream O Given 10 minutes to rate them O Told they could eat as much as they wanted O Afterwards they answered a questionnaire to assess whether they were restrained eaters
  24. 24. O HIGH RESTRAINT GROUP O Ate significantly more ice cream in the one and two milk shake conditions than in the zero milk shake condition.
  25. 25. O Herman and Mack found a significant positive correlation across all participants between the eating restraint questionnaire and amount eaten after two preloads (milk shakes). O The higher the restraint score, the more they ate after 2 milkshakes.
  26. 26. O The results support a boundary model of dietary restraint. O Restrained eaters have a ‘cognitive’ dieting boundary for food intake.
  27. 27. What the hell-effect? O Eating is disinhibited because the restrained eater feels they’ve already ‘blown it’ so they might as well carry on.
  28. 28. Restrained eater in Herman and Mack’s study Low calorie preload (one or zero milk shake) High calorie preload (2 milk shakes) O Is still within the diet O Pushed beyond the boundary O In the ‘taste test’ eats enough to reach this boundary (not much) cognitive boundary before the taste test (ice cream). O This disinhibits their feeding behaviour and they simply eat until they reach the physiological boundary (more than in the preload condition).
  29. 29. Evaluation of methodology O The restraint questionnaire was given after the feeding tests so the division of each group into high and low-restraint groups was post-hoc (done after the study had been carried out). O Ideally this should be done before but Herman and Mack felt that this would have led to demand characteristics.
  30. 30. O This meant that there were unequal numbers in the high- and low-restraint groups (e.g. 9 high-restraint and 6 lowrestraint in the 2nd condition). O This uneven pattern reduces the reliability of the findings.
  31. 31. O Group sizes were quite small especially after the division into high- and lowrestraint participants. O Some participants may have liked ice cream more or less than others. Three varieties were provided to try to deal with this, but it is still possible that dislike of ice cream (or particular liking) may have biased the findings.
  32. 32. The Boundary Model Hunge r No Preload Satiet y Unrestrained Eaters Preload O Unrestrained eater eats until satisfied (as determined by their body weight set point
  33. 33. The Boundary Model Hunge r Satiet y Restrained Eaters No Preload Preload Cognitive O Restrained eater eats until reach cognitive boundary (as boundary determined by themselves) O Low-cal preload means they stay within their boundary O High-cal preload means they are pushed beyond their boundary which disinhibits their feeding behaviour so eat until satisfied
  34. 34. Evaluation of Theory  Does not explain why we become disinhibited Implications for obesity Overeating may be a consequence of restraint if this is recommended as a treatment.  Limited relevance Can’t explain how anorexics never experience the disinhibition effect.
  35. 35. Over eating O Herman and Polivy (1980) suggested that there is a causal link between dieting and binging. O ‘Restraint not only precedes over- eating but contributes to its causality’ O The theory is that attempting not to eat will increase the probability of you over eating.
  36. 36. Key study: Wardle and Beales (1988) O Aim: to investigate whether dieting resulted in over eating O Procedure: lab procedure assessing food intake at 4 and 6 weeks. Pp’s randomly assigned to diet group, exercise group or control. O Participants:27 obese women. O Findings: Pp’s in diet condition ate more than those in exercise and control group. Key strengths: •Experimental design, which means manipulation could take place: diet v’s not dieting. • Random allocation of pp’s to conditions. •Lab conditions: high control •A non student sample: results should be more generalisable. Supports causal link between dieting and over eating. Tested the causal analysis of over eating Key weaknesses: •Small sample size •Pp’s alternative agenda? Did they comply with what they were asked to do? •Non- natural setting: what kind of problems might this bring?
  37. 37. Denial O When denying ourselves something it often has the opposite effect The theory of ironic processes of mental control O Attempts to suppress thoughts about particular things only serves to increase preoccupation with them O Restrained eaters O Bulimics O Anorexics 38
  38. 38. White Bear Study O Wegner at al (1987) O Asked some participants to NOT THINK about a white bear and ring the bell when they do O Also asked other participants to THINK about the bear O THOSE THAT WERE TOLD TO NOT THINK ABOUT THE BEAR RANG THEIR BELLS MORE OFTEN. 39
  39. 39. Applying this to real life. O Have a think about how you might feel if you are told not to do something. O For example ‘do not look at the big spot on your teachers nose’ O What is the first thing that you are going to do? Eating food works on the same principle: if you wake up and you decide you are not going to eat chocolate today, you will crave and want to eat chocolate all day. With this in mind: what problems might health professionals face when trying to help people to eat less?
  40. 40. Evaluation of theory of ironic processes/denial O Wegner himself acknowledges that the effects observed in experimental research in this area are small 41
  41. 41. Evaluation of failure of dieting research Strengths Use of experimental research: ensuring that key variables are manipulated and controlled. Finding reflect peoples experiences: reflect experiences of many people who have tried to lose weight by limiting what they eat. Weaknesses: Limitation of restraint as a explanatory theory: How could it explain the eating behaviour of people suffering from anorexia? How do they manage to starve themselves when they spend most of their lives restricting their food intake. Laboratory experiment: Most of the studies used to support evidence of dieting has been conducted in a laboratory experiment. Therefore lack ecological validity.
  42. 42. What leads to success in dieting? O Not feeling bored - variety O Redden (2008) Jelly Bean experiment O Redden had participants eat 22 fruit-flavoured jelly beans (cherry, orange, strawberry, peach, tangerine) while rating their enjoyment. At the end, participants were asked to indicate how repetitive the eating task felt, how similar the jelly beans seemed to each other, and how much variety they perceived. O People given specific flavour labels (e.g., cherry) became less bored and fed up and kept enjoying the jellybeans longer than people given the general label of 'jellybean'," O Redden reveals. In other words, though everyone ate the same variety of jellybeans, people who were just given "jellybeans" to eat as opposed to "tangerine jellybeans" and "strawberry jellybeans" gave lower assessments as the experiment wore on, though both groups rated the jellybeans about equally toward the beginning of the experiment. 43
  43. 43. Theories of Dieting Success SUCCESS IN DIETING – Redden (2008) The key is to pay attention to the detail. 135 participants Each given 22 jelly beans. GROUP ONE GROUP TWO General information given Specific information Bean number 7 Cherry flavoured bean number 8 Participants got bored with eating beans faster if they saw the general information and enjoyed task more with specific info.
  44. 44. Success of Dieting- Redden O This research shows the decline in enjoyment of an eating regime depends on how much repetition people perceive, O The study also has implications for our understandings of dieting. Variety of categories is especially useful when facing limited options or following a repetitive regimen. O The research establishes that subcategorization offers people the potential to make their lives more enjoyable." 45
  45. 45. O Redden (2008)- Secret to sucessful dieting is in the detail. O The dreaded salad – ‘not another salad’, O Should focus on the type of tomatoes in it or the salad leaves e.g. rocket etc.
  46. 46. Research has found... O A number of psychological variables influence the success of dieting: Rodin et al (1977) carried out a study to assess the baseline psychological predictors of successful weight loss. They found that individuals beliefs about the cause of obesity and motivation for weight loss played an important role. Williams et al (1996) also reported that motivational style was predictive of weight loss and weight motivation. Kiernan et al (1998) reported that individuals who were dissatisfied with their body shape at baseline were more successful at dieting. They suggested that motivation for weight loss and a high value placed on attractiveness may be important.
  47. 47. Study: Ogden and Mills (2008) O The study: Interviewed pp’s who had lost weight and maintained their weight loss. O Findings: pp’s reported that much of their weight loss had been triggered by a key life event, e.g: divorce, illness or a milestone (like turning 40!). This initial behaviour was then translated into long term behaviour change if a number of sustaining conditions were met: A belief in a behavioural model of obesity A reduction in the benefits and function of eating A process of reinvention (no longer seeing themselves as an over weight person )
  48. 48. Study: Ogden and Mills (2008) continued .... O The results suggested that it is not only what individuals do that is predictive of success, but also what they believe. For dieting to be successful, a person needs to: Hold a model of obesity that focuses on behaviour as central to their weight problem Create a situation whereby food is no longer considered as rewarding. Avoid a state of denial whereby they want to eat but do not. Establish a new identity as a thinner person
  49. 49. Social support- dieting success Successful weight loss is strongly associated with social support, according to Psychology Today. There are many options available. Non-profit Support Groups Commercial Diet Program Support Internet Weight-Loss Communities Weight-Management Coaching Support Through Social Media 50
  50. 50. Dieting success O Psychologist Sherry Pagoto advises dieters to seek social support through social media. ‘Consider starting your own blog or making use of Facebook or Twitter to find a supportive social circle of like-minded individuals.’ 51
  51. 51. Successful weight loss O Can be achieved if combined with life-style changes: - Physical exercise - Group and individual support - Self-monitoring - Perhaps the most successful way to lose weight is not dieting but following a healthy eating plan 52
  52. 52. 5 diet success stories O http://www.youtube.com/watch?v=l-ZV- v7SLLk O Can you see any similarities to research findings discussed this lesson?
  53. 53. Evaluation O Concerns over effectiveness and potential damaging effects of many diet programmes led to shows aimed at replacing dieting with healthy eating. O A meta-analysis of anti-dieting shows found participants improved in both eating behaviour and psychological wellbeing as well as weight stability rather than weight change. 54
  54. 54. IDA O Culturally biased O Research tends to be Eurocentric O Some cultures find it more difficult to diet because of a natural inclination for obesity (Park et al, 2001) O Gender biased O Mostly women volunteer O Ironically excess weight is more detrimental for men O However research is changing with greater awareness of cultural variations in eating behaviour and gender differences 55

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