Eating behaviour.

Lesson 6: Explanations for the failure of dieting.

Lesson objectives

• 1) to be able to describe reasons why dieting may not be successful.

• 2) To develop an a deeper understanding of reasons why people may not succeed in dieting.

• 3) To be able to evaluate research evidence into dieting.

Starter

• Discuss in pairs: What explanations might there be for why dieting might be unsuccessful?

• You have 2 minutes to write down as many as you can.

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When is dieting not successful?

• A number of research studies have found that dieting is some times unsuccessful and can lead to overeating.

Ruderman and Wilson (1979) conducted a lab study, to explore eating behaviour using a preload/ pre test procedure.The study involved: giving P’s either a high calorie preload (E.G. a high calorie milk shake) or a low calorie pre load (E.G. A cracker).

After eating or drinking the pre load, P’s were asked to take part in a taste test – asked to rate different foods on a variety of qualities (E.G. Sweetness and saltiness preference)

P’s were then left alone and given a certain amount of time to rate the foods. The amount they ate was also recorded

The aim of the preload/taste test was to measure food intake and to examine the effect of pre loading on eating behaviour.

What did Ruderman and Wilson (1979) find?

• Restrained eaters consumed significantly more food than unrestrained eaters, irrespective of the size of the pre load.

Why do you think this might be?

Restraint theory identified that: disinhibition of restraint (like thinking ‘what the hell?’) is a classical characteristic of over eating in restrained eaters.

Disinhibition has been described as ‘ eating more as a result of loosening restraints in response to emotional distress, intoxication or preloading’.

Activity:

• Have a look at Herman and Mack’s (1975) original study on page 170.

• Answer the following questions:• 1) What was the procedure of the

study?• 2) What kind of a sample was

used?• 3) What did the study find?• 4) Why has this study triggered a

new way of thinking?Extension activity: How could we evaluate this study?

You have 10 minutes to do this

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Possible causes of over eating

• Research has investigated into possible reasons for why people overeat.

The causal analysis of over eating

Mood modification and denial

The causal analysis of over eating

• Herman and Polivy (1980) suggested that there is a causal link between dieting and binging.

• ‘Restraint not only precedes over-eating but contributes to its causality’

• The theory that attempting not to eat will increase the probability of you eating.

Applying this to real life.

• Have a think about how you might feel if you are told not to do something.

• For example ‘do not look at the big spot on your teachers nose’

• 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?

Key study: Wardle and Beales (1988)

• Aim: to investigate into whether dieting resulted in over eating

• Procedure: Lab procedure assessing food intake at 4 and 6 weeks. P’s randomly assigned to diet group, exercise group or control.

• Participants:27 obese women.

• Findings: P’s in diet condition ate more than those in exercise and control group.

Tested the causal

analysis of over eating

Supports causal link between dieting and over eating.

Key strengths:•Experimental design, which means manipulation could take place: diet v’s not dieting.• Random allocation of P’s to conditions.•Lab conditions: High control•A non student sample: results should be more generalisable.

Key weaknesses:•Small sample size•P’s alternative agenda? Did they comply with what they were asked to do?•Non- natural setting: what kind of problems might this bring?

Mood modification• The ‘masking hypothesis’• It has been found that dieters tend to

over eat in response to lowered mood.

• Masking their failure of something by over eating.

• Researchers argue that disinhibitory behaviour enables the individual to mask negative moods with the temporary heightened mood caused by eating.

Tested by Polivy and Herman (1999). They found that when were told they had failed on a cognitive task, dieters who ate as much as they liked attributed more of their distress to their eating behaviour than to failure on the task.

Q: can you see how this might support the masking hypothesis?

Evaluation: Research evidence on dieting

• Q: How might we evaluate research evidence on dieting.

• You have two minutes in pairs to develop your ideas.

Did you think of these points?

• Research places an emphasis on body disatisfaction – which is a common determinant of the ways people eat

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 loose weight by limiting what they eat.

Strengths: 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.

Activity

• Create a psychology self help leaflet, providing advice for people who would like to loose weight.

• Relate it back to material covered in this lesson and last lesson.

• You could also include a section on denial.

Plenary

• Presentation of self help sheets so far.

Homework

• To complete your self help sheet.