Explanations for the failure and success of dieting Flashcards
Explanation for failure: weight set point
- The set point theory expresses how there is a control system built into every person which dictates how much fat that person should carry.
- The body has a range of weight that it is comfortable within (about 5% either side of its current weight)
- This can explain why repeated dieting can be unsuccessful, as the set point is v good at restoring imbalance
- The WSP is largely genetic as each body has its own wsp. Because of this innate biological response, dieting becomes progressively less effective and a plateau is reached
- wsp is the optimum weight set for stable optimistic mood; dieting puts us in opposition to wsp; so if our weight falls below wsp then our metabolic rate decreases
Keys et al
-study of semi-starvation during world war 2, participants who were young men agreed to lose 25% of their body weight, they consumed 50% of their normal intake.
They initially lost weight quickly, however their weight lost reached a plateau and they became irritable and hungry and obsessed with food. They avoided physical activity and had strong urges to overeat.
How does keys et al support the WSP theory?
-This supports the WSP because it shows how they dieted and lost weight initially but soon plateaued. They also became extremely irritable because they went below their optimal weight for optimistic mood. This is therefore evidence that the body ‘defends’ its fat stores once weight goes below the set point. The showed a decrease in metabolic rate which caused them to avoid physical activity so they burned fewer calories. They also had strong urges to overeat and became obsessed with the thought of food.
Adopted children’s weight is more similar to that of their biological parent then their adoptive parents. MZ twins even when reared apart are more similar in terms of weight than DZ twins.
This supports WSP explanation, because there was a greater similarity in weight in MZ’s who share 100% of genes, compared to DZ’s who share 50% of genes, suggesting that weight is at least partly under genetic control.
Explanation for failure: Boundary model
-Herman and Mack supports the boundary model as an explanation for dieting failure, as they found that dieters who were given a high preload snack (high calories) ate more in the taste test then the dieters who were given the no preload snack. This is evidence for the boundary model because it shows that if restrained eaters go beyond the cognitively determined diet boundary, they think ‘what-the-hell’ and eat up to the satiety boundary.
Boundary model; methodological Herman & Mack
X smaller sample + unrepresentative ( used 45 women; gender bias)
O Direct support with control group
X Lab experiment - not in a setting where dieting happens.
X Social desirability; hold back from eating; although did not know intake was being measured
-Real world dieting may involve more complicated processes then those in the lab
-Study involved deception which overcomes demand characteristics (unethical ?)
-Model doesn’t specify the cognitive and emotional processes that lead to the ‘what-the-hell’
Explanation for success: Ogden’s psychological model
- Ogden proposes that key psychological factors explain the difference between success/unsuccessful:
- See obesity less in terms of genetic + hormonal and more in terms of their own behaviour
- View of psychological motives for losing weight as important
- Use psychological techniques such as establishing a new identity as a thinner person.
Ogden study:
-Questionnaire to explore factors associated with success in weight loss + maintenance
-stable obese, weight loss re-gainer, weight loss maintainers
Results: WLM had spent longer dieting and were less likely to endorse medical explanations for obesity than the others
-They have been more motivated to lose weight for psychological reasons, rather than as a result of pressure from others.
The extent to which Ogden supports the psychological model
-This supports Ogden’s psychological model because is shows that the WLM view psychological motives for losing weight as important and use psychological techniques to establish a new identity as a thinner person. They also are aware of the psychological consequences of being obese, such as depression + anxiety.
Ogden + Hills:
-WLM often reported that weight loss triggered by real life events such as divorce. Supports the model because it shows successful dieters establish a new identity and evidence for the importance of psychological motivation
Explanation for success: Attention to detail
-A further explanation is that successful dieters are able to pay attention to the details of a healthy diet.
Redden (2008)
- 22 pps ate fruit flavoured jelly beans while rating their enjoyment.
- At the end pps were asked to indicate how well they could distinguish the flavours, how repetitive the task felt and the variety of the jelly beans.
- Those given specific flavour levels became less satiated and enjoyed the jellybeans longer.
- Even though everyone ate the same variety of jellybeans, those given variety gave higher assessments.
Problems with dieting
- Research is arguably ethnocentric
- Park et al suggests that some cultures encounter more difficulties with weight loss
- Arguable that dieting is a western concern
- E.g in some cultures larger is seen as more desirable
Free will and determinism for failure and success of dieting
- If eating behaviour is determined by inherent taste and food preferences, then we have no free will over what and how much we eat.
- However is our food preferences are learned during childhood, then we may not have much choice over what we eat.
Practical applications
-A positive practical application is that researchers can find the most successful way to diet and so to help obese people improve their health
