psychological explanations for obesity

What are some psychological explanations for obesity not mentioned in the spec?

SLT, learning theory, cognitive explanation

What is obesity?

Being extremely overweight - having a BMI of over 30.

What are the three different psychological explanations for obesity?

Restraint theory

Boundary model

Disinhibition

RESTRAINT THEORY: What is restraint?

The intentional restriction of food intake in order to prevent weight gain.

What does restraint theory suggest?

That attempting to reduce food intake actually increases the probability of overeating.

How does restraint theory explain obesity?

Probability of overeating increasing leases to weight gain and therefore a higher risk of becoming obese.

What are the different types of restraint?

‘Rigid’ restraint - all-or-nothing approach

‘Flexible’ restraint - less strict approach where unhealthy foods can be eaten in limited quantities without guilt

BOUNDARY MODEL: What does this model suggest?

That food intake is regulated along a scale - with hunger at one end and fullness at the other.

These are boundaries.

What is food intake driven by, according to this model?

Biological processes.

Explain the boundaries

Hunger boundary - energy levels are low, causing hunger.

Satiation boundary - we stop eating because of the unpleasant feeling of fullness, energy levels are sufficient

Explain the boundary model of dieters.

(2 points)

Low threshold for hunger (get hungry quickly) and a higher threshold for satiation.

They have a larger zone of biological indifference.

They also have a self-imposed diet boundary.

What is biological indifference?

Where hunger and satiety are both absent

Explain the diet boundary.

It is cognitively determined and represents what the dieter believes the amount they should eat.

It is set lower than the satiation threshold.

How does the boundary model explain the cause of obesity?

If the dieter goes over their limit, they experience the ‘what the hell’ effect - the person stops caring about their diet as the boundary has already been surpassed.

The person continues to eat until beyond satiation.

This counteracts the progress of other days of successful dieting, leading to weight gain and higher chances of obesity.

DISINHIBITION: Definition of disinhibition

The tendency to overeat in response to different stimuli.

What happens in these situations that enable disinhibition?

The normal inhibitions that prevent us from overeating are removed.

How does this lead to obesity?

As the lack of normal inhibitions make us respond less to feelings of satiation, and so are more susceptible to overeating.

This leads to weight gain and therefore a higher risk of obesity.

What are the different types of disinhibition?

Habitual disinhibition

Emotional disinhibition

Situational disinhibition

Explain the different types of disinhibition.

Habitual - overeating in response to daily life circumstances

Emotional - overeating due to anxiety or depression, food provides a comfort

Situational - Overeating in response to specific environmental contexts (eg wedding buffets, parties)

Positive eval

Research support for restraint theory - Wardle and Beales (1988) found that obese women on a diet ate more than obese women not on a diet. They did this by comparing the two groups under laboratory conditions, after a ‘preload’ (a snack, eg a chocolate bar).

RWA - obese people know not to restrain their eating if they want to lose weight, they can instead change their lifestyle.

Research support for boundary model (or can be used to support disinhibition) - Herman and Mack’s milkshake study (1975). Restrained eaters who consumed a milkshake preload went on to eat more ice cream than participants who had not consumed the preload. This supports the boundary model because it suggests restrained eaters rely more on cognitive boundaries than internal hunger and satiety cues when regulating food intake. Once this cognitive boundary is disrupted, restrained eaters may overeat beyond their normal satiety level - “what the hell effect”. Therefore, the findings increase the validity of the boundary model as an explanation for overeating and obesity.

Negative eval

Restraint theory lacks validity - Tomiyama (2009) pointed out that restraint theory’s research is based largely on lab studies. These aren’t applicable to real-life. He found that dieters didn’t overeat after violations of their diet.

Lacks cultural relativism - most research on disinhibition has been on white women, so can’t be generalised to other cultures. Atlas (2002) found that referring

The psychological explanation for obesity overlooks biological factors.