Psychological explanations of obesity | AQA A-Level Psychology Revision
- Revision Notes
- Aug 6
- 22 min read
Updated: Aug 14
For 7182 specification, first teach in September 2025
AQA A-Level Psychology | Free Revision Notes
Estimated study time: 65 minutes
These psychological explanations of obesity A-Level Psychology revision notes examine why deliberately restricting food can sometimes produce the opposite of the intended effect. You will study restraint theory, disinhibition and the boundary model, including hunger and satiation boundaries and the zone of biological indifference. These explanations complement genetic and neural accounts [Biological explanations of obesity] by showing how thoughts, dietary rules and social influences may affect eating within the body’s biological limits.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define restraint, disinhibition and the boundary model.
Explain how restrained eating may produce a paradoxical increase in food consumption.
Explain how breaking a dietary rule can lead to disinhibited eating.
Describe the hunger boundary, satiation boundary and zone of biological indifference.
Apply psychological explanations of obesity to unfamiliar scenarios.
Evaluate restraint theory, disinhibition and the boundary model.
Revision Notes 📚
What does the AQA specification require?
For Eating behaviour, AQA requires students to study:
Biological explanations for obesity, including genetic and neural explanations.
Psychological explanations for obesity, including restraint theory, disinhibition and the boundary model.
These are the only named psychological explanations of obesity required by the specification.
You must be prepared to:
Explain restraint theory.
Explain disinhibition.
Describe how the boundary model combines biological and psychological influences.
Apply the explanations to dieting and overeating scenarios.
Evaluate their strengths and limitations.
What is a psychological explanation of obesity?
A psychological explanation focuses on mental processes and patterns of behaviour that may contribute to overeating and weight gain.
These explanations do not suggest that every person with obesity follows the same pattern. Instead, they propose that obesity may sometimes be associated with:
Deliberate attempts to restrict eating.
Self-imposed dietary rules.
Preoccupation with food.
The abandonment of restraint.
Eating beyond a planned limit.
Cognitive and social influences on food intake.
The central idea is slightly counter-intuitive:
Trying very hard to restrict food can sometimes increase the risk of overeating.
This is known as the paradoxical effect of restraint.
Restraint theory
Restraint theory proposes that attempts to restrict food intake can sometimes lead to increased eating rather than successful long-term restriction.
A restrained eater deliberately tries to control how much they eat. They may follow rules such as:
“I must not eat between meals.”
“I cannot eat this type of food.”
“I must remain below a particular daily limit.”
“Eating more than planned means the diet has failed.”
The person’s food intake is therefore regulated partly by conscious thought rather than only by biological hunger and satiation.
Restraint theory is not simply the claim that dieting causes obesity. It proposes a particular process in which rigid restriction may make overeating more likely.
Cognitive control of eating
Restrained eaters attempt to use cognitive control to override the motivation to eat.
This means that eating is influenced by mental rules concerning:
Which foods are permitted.
How much may be eaten.
When eating is acceptable.
Whether the diet is succeeding.
What counts as breaking the diet.
For example, a person might feel hungry but refuse to eat because their rule states that they cannot eat before a particular time.
The rule, rather than hunger alone, controls their behaviour.
The paradoxical effect of restraint
A paradoxical effect occurs when an action produces the opposite of its intended result.
Dietary restraint is intended to reduce food consumption. However, restraint theory proposes that strict restriction may eventually increase consumption.
The proposed sequence is:
The person decides to restrict food.
They create strict rules about what or how much they may eat.
Restricted foods become increasingly noticeable or psychologically important.
The person becomes preoccupied with eating.
A dietary rule is broken.
Restraint is abandoned.
The person eats more than they would have done without the restrictive rule.
The intention was to consume less, but the outcome may be overeating.
Preoccupation with food
Restricting food may make thoughts about food more frequent or intense.
Foods that are labelled “forbidden” may become especially noticeable. The restrained eater may:
Think frequently about the food they are avoiding.
Pay increased attention to opportunities to eat it.
Interpret eating a small amount as a major failure.
Find it increasingly difficult to maintain the restriction.
AQA’s application material recognises that intense preoccupation with food may contribute to increased eating because forbidden foods become more salient.
This does not mean that merely thinking about food automatically causes obesity. The explanation concerns how preoccupation may combine with restrictive rules and subsequent disinhibition.
Restrained and unrestrained eating
Restrained eating | Unrestrained eating |
Food intake is deliberately limited through cognitive rules | Eating is not governed by strict dieting rules |
The person may ignore hunger to remain within the diet | The person may respond more directly to hunger and satiation |
Foods may be divided into permitted and forbidden categories | Foods are less likely to be treated as evidence of success or failure |
Breaking a rule may trigger disinhibition | Eating one food does not necessarily mean all control has failed |
Restriction and overeating may alternate | Eating may be less affected by rigid self-imposed limits |
This comparison does not mean that unrestrained eating always produces healthy intake. It explains the different role played by dietary rules.
What is disinhibition?
Disinhibition is a loss of restraint that leads to unrestrained eating.
The person temporarily abandons the rules that had been controlling their food intake.
For example:
A person plans to avoid all desserts. After eating one biscuit, they decide that the diet has already failed and eat several more foods they had intended to avoid.
The first biscuit does not biologically require the person to continue eating. The overeating is explained by a cognitive judgement that the dietary rule has been broken.
The June 2023 assessment distinguished restraint, meaning the regulation of food consumption, from disinhibition, meaning unrestrained eating.
The “what the hell” effect
The “what the hell” effect describes the reaction that may occur when a restrained eater believes that their diet has been broken.
The person may think:
“I have already failed, so there is no point continuing to restrict myself today.”
This produces an all-or-nothing response:
Remaining within the diet counts as success.
Crossing the limit counts as complete failure.
Once failure has occurred, further restraint appears pointless.
The sequence may be written as:
Dietary rule → rule is broken → perceived failure → restraint is abandoned → disinhibited eating
The effect helps explain why eating a relatively small amount beyond the planned limit may be followed by much greater consumption.
Disinhibition is not the same as hunger
Disinhibited eating does not necessarily occur because the person has suddenly become extremely hungry.
It concerns the removal of psychological restraint.
Hunger | Disinhibition |
A biological motivation to eat | A psychological loss of dietary control |
Can occur without a person being on a diet | Depends on restraint or self-imposed rules being abandoned |
Eating is motivated by an energy deficit | Eating may follow the judgement that the diet has failed |
Usually reduces as food is consumed | May continue despite the person having eaten a substantial amount |
Hunger and disinhibition may occur together, but they are different concepts.
The restraint-disinhibition cycle
Restraint and disinhibition may form a continuing cycle.
The person feels dissatisfied with their previous intake or weight.
They begin a strict diet.
Food intake is restrained.
Hunger and preoccupation with food increase.
A dietary rule is broken.
Disinhibited eating occurs.
The person regrets the overeating.
They begin another restrictive diet.
This cycle may contribute to repeated loss and regain of weight, sometimes described as yo-yo dieting.
The key explanatory point is that renewed restriction may recreate the conditions that previously led to disinhibition.
Applying restraint and disinhibition
Consider this scenario:
Evie follows a strict rule that she must not eat chocolate. At a celebration, she eats one chocolate and decides that her diet has been ruined. She then eats several desserts, even though she no longer feels hungry. The next morning, she begins an even stricter diet.
A developed application would explain:
Evie’s rule about chocolate demonstrates restraint because she is cognitively regulating food intake.
Eating one chocolate crosses her self-imposed dietary limit.
Her belief that the whole diet is ruined demonstrates all-or-nothing thinking.
Eating several desserts shows disinhibition because restraint has been abandoned.
Continuing despite not feeling hungry shows that the behaviour is not explained only by biological hunger.
Beginning a stricter diet may restart the restraint-disinhibition cycle.
The boundary model
The boundary model combines restraint and disinhibition with the biological regulation of eating.
It proposes that eating is governed by two biological boundaries:
The hunger boundary
The satiation boundary
Between these boundaries is the zone of biological indifference.
Within this zone, a person is neither biologically compelled to begin eating nor biologically compelled to stop. Cognitive and social influences can therefore play an important role.
The model recognises both physiological regulation and psychological control.
The hunger boundary
The hunger boundary is the lower boundary in the model.
When the body’s energy state moves beyond this boundary:
A biological deficit is detected.
Hunger becomes strong.
The person is motivated to eat.
At this extreme, food intake is mainly controlled by biological need.
Knowledge of biological hunger mechanisms [Neural control of eating] can help you understand why the boundary model includes physiological limits.
The satiation boundary
The satiation boundary is the upper boundary.
When sufficient food has been consumed:
Fullness increases.
The motivation to continue eating reduces.
Eating stops.
At this extreme, food intake is again strongly influenced by biological mechanisms.
This connects the model with ghrelin, leptin and appetite regulation [Hormonal control of eating].
The zone of biological indifference
The zone of biological indifference is the space between the hunger and satiation boundaries.
Within this zone:
The person is not so hungry that eating must begin.
The person is not so full that eating must stop.
Biological signals do not completely determine behaviour.
Cognitive and social factors can influence whether eating occurs.
Possible influences include:
Dietary rules.
The presence of food.
Social situations.
Expectations about how much should be eaten.
Judgements about whether the diet has succeeded or failed.
This zone is essential to the model. It explains why people may eat without intense hunger or stop before reaching physiological satiation.
The self-imposed diet boundary
A restrained eater creates an additional diet boundary within the zone of biological indifference.
This is a psychological limit representing how much the person believes they are allowed to eat.
For example:
The hunger boundary may motivate the person to begin eating.
The diet boundary states when they believe they should stop.
The satiation boundary represents when biological fullness would stop eating.
The restrained eater intends to stop at the diet boundary, before reaching physiological satiation.
What happens when the diet boundary is crossed?
If the restrained eater remains within the diet boundary, cognitive control is maintained.
If the diet boundary is crossed:
The person interprets the diet as broken.
Restraint is abandoned.
Disinhibition occurs.
Eating may continue through the zone of biological indifference.
The person may not stop until the satiation boundary is reached.
This is why restrained eaters may sometimes consume more after breaking a diet than people who were not restraining their eating.
A simplified boundary model
The model can be represented as:
Hunger boundary → zone of biological indifference → satiation boundary
For a restrained eater, a self-imposed limit is added:
Hunger boundary → diet boundary → remaining zone → satiation boundary
The person intends to stop at the diet boundary. Once that boundary is crossed, disinhibition may result in eating continuing towards satiation.
Restraint, disinhibition and the boundary model compared
Explanation | Central idea | How it may contribute to obesity |
Restraint theory | Deliberately restricting food may have a paradoxical effect | Restriction may increase preoccupation and later consumption |
Disinhibition | Dietary control is abandoned | The person may eat substantially more after deciding that the diet has failed |
Boundary model | Eating is regulated by biological boundaries and psychological limits | Crossing the diet boundary may produce disinhibition and eating until physiological satiation |
These are overlapping explanations rather than completely independent theories.
The boundary model incorporates restraint and disinhibition into a broader account of eating.
A complete psychological explanation
A developed explanation might state:
A restrained eater imposes a cognitive diet boundary within the zone between biological hunger and satiation. If this self-imposed boundary is crossed, the person may interpret the diet as a failure and become disinhibited. They may then continue eating until the higher satiation boundary is reached. Repeated cycles of restraint and disinhibition could contribute to excessive intake and obesity.
This explanation includes:
Restraint.
A self-imposed boundary.
Biological hunger and satiation.
Disinhibition.
The link to obesity.
Applying the boundary model to a scenario
Consider this example:
Reuben allows himself one small evening meal. One night, he eats more than planned at a restaurant. He decides that he may as well continue eating and orders several additional dishes. He says that he does not stop until he feels uncomfortably full.
A developed answer could explain:
One small meal is Reuben’s self-imposed diet boundary.
Eating more than planned means that boundary has been crossed.
Deciding that he may as well continue demonstrates the “what the hell” effect.
Ordering additional food shows disinhibition.
Continuing until he feels very full suggests eating towards the biological satiation boundary.
Repeated episodes could increase overall energy intake and contribute to obesity.
Application checklist
For an application question:
Identify the dietary rule.
Explain how it demonstrates restraint.
Identify the point at which the rule is broken.
Explain the loss of restraint.
Identify evidence of disinhibited eating.
Link the behaviour explicitly to obesity.
Avoid merely writing:
“Reuben crossed the boundary and became disinhibited.”
A developed answer must identify which boundary was crossed and explain the behavioural consequence.
Evaluating restraint theory
Support for the paradoxical effect
A strength of restraint theory is that evidence indicates restrained eaters may sometimes eat more rather than less.
This supports the theory’s central prediction:
Restriction does not always reduce intake.
Breaking a diet can produce increased eating.
Restraint may therefore have a paradoxical effect.
The 2022 AQA mark scheme identifies evidence that restrained eaters may consume more, as well as evidence for the “what the hell” effect, as relevant evaluation of psychological explanations of obesity.
This evidence supports the proposed link between restraint and subsequent overeating.
However, it does not mean that every diet fails or that restraint always causes obesity.
Restraint may increase food salience
The explanation is strengthened by its ability to account for preoccupation with food.
When foods are treated as forbidden:
Attention may become focused on them.
Thoughts about eating may become more frequent.
Breaking the rule may become increasingly likely.
The restrained eater may react strongly to a small lapse.
This provides a plausible cognitive mechanism connecting restriction with overeating.
However, food preoccupation may also be a consequence of hunger produced by low food intake. Psychological and biological mechanisms may therefore be difficult to separate.
Restraint does not always lead to disinhibition
A limitation is that many people restrict food without subsequently overeating.
Some people may:
Follow flexible rather than rigid rules.
Respond to a lapse by returning to their plan.
Avoid interpreting one food choice as complete failure.
Maintain dietary changes without repeated disinhibition.
Restraint theory may therefore explain some unsuccessful dieting patterns better than all attempts to control food intake.
It needs to account for individual differences in whether restraint leads to disinhibition.
Evaluating disinhibition
It explains sudden changes in eating
Disinhibition helps explain why a person may move rapidly from strict control to unrestrained consumption.
The behaviour may appear irrational if only hunger is considered. It becomes more understandable when the person’s cognitive judgement is included:
“The rule has already been broken, so further restraint no longer matters.”
This gives disinhibition explanatory value because it identifies the mechanism linking a small dietary lapse with much greater consumption.
It may describe maintenance rather than original cause
A major limitation is that disinhibition may explain how overeating continues without explaining why the person first became a restrained eater.
The explanation may describe:
Why dieting fails.
Why overeating follows restriction.
Why weight may be regained.
Why cycles of dieting occur.
It may not fully explain:
Why the person originally developed concerns about weight.
Why they adopted rigid dietary rules.
Why one person becomes restrained while another does not.
Why obesity developed before the dieting began.
The AQA mark scheme recognises that psychological explanations may describe thinking patterns associated with obesity without explaining their original cause.
Evaluating the boundary model
It combines psychological and biological mechanisms
A strength of the boundary model is that it does not ignore biological regulation.
The model recognises:
Hunger as a biological signal.
Satiation as a biological stopping mechanism.
A zone in which cognitive and social factors influence eating.
Self-imposed dietary control.
Disinhibition after the diet boundary is crossed.
This makes the model less narrowly reductionist than an explanation based only on thoughts or only on physiology.
It connects naturally with biological mechanisms of weight regulation [Biological explanations of obesity].
It explains why restraint and disinhibition overlap
The boundary model does not treat restraint and disinhibition as unrelated.
Instead:
Restraint creates the diet boundary.
Crossing the diet boundary produces perceived failure.
Perceived failure leads to disinhibition.
Disinhibition allows eating to continue towards satiation.
Subsequent regret may lead to renewed restraint.
This continuous cycle is a strength because it accounts for alternating periods of strict dieting and overeating.
It recognises social and cognitive influences
The model explains why eating may occur when a person is neither extremely hungry nor completely full.
Within the zone of biological indifference, intake may be affected by:
Dietary rules.
Beliefs about success and failure.
The availability of food.
Social circumstances.
Expectations about eating.
This produces a broader account than a purely homeostatic explanation.
Boundaries may be difficult to measure
A limitation is that the boundaries are theoretical concepts.
It may be difficult to establish objectively:
The exact point at which hunger begins.
The exact point at which satiation is reached.
Where a person has placed their diet boundary.
Whether different people experience boundaries in the same way.
Whether the boundaries remain stable over time.
If boundaries cannot be operationalised clearly, testing the model precisely becomes difficult.
The model may oversimplify obesity
Although the boundary model includes both biology and cognition, obesity is likely to involve additional influences.
These may include:
Genetic vulnerability.
Neural regulation.
Hormonal mechanisms.
Learned food preferences.
Social and cultural factors.
Differences in the person’s wider environment.
The boundary model may explain episodes of overeating without providing a complete account of every case of obesity.
Cause and effect
Evidence that restraint and obesity occur together does not prove that restraint caused obesity.
Several directions are possible:
Restraint leads to disinhibition and later weight gain.
Previous weight gain leads the person to begin dieting.
A third factor contributes to both obesity and restraint.
Restraint and overeating reinforce one another over time.
This makes simple causal conclusions difficult.
A cautious conclusion would be:
Restraint may contribute to overeating in some people, but it may also begin as a response to existing concerns about weight.
Comparison with biological explanations
Psychological and biological explanations emphasise different mechanisms.
Psychological explanation | Biological explanation |
Focuses on dietary rules and cognitive control | Focuses on genes and neural mechanisms |
Explains restraint and disinhibition | Explains inherited or physiological vulnerability |
Eating may continue because a rule has been broken | Eating may continue because satiation signals are ineffective |
Emphasises nurture and experience | Emphasises nature and internal biology |
May explain dieting failure | May explain differences in appetite regulation |
Psychological explanations can be criticised for underestimating biological vulnerability. Biological explanations can be criticised for underestimating the person’s thoughts and dietary practices.
An interactionist conclusion is often strongest:
Biological mechanisms may establish hunger and satiation limits, while cognitive rules influence eating between those limits.
This connects with the relative contribution of heredity and experience [The nature-nurture debate].
Psychological reductionism
Restraint and disinhibition may be criticised for explaining obesity mainly through a small number of cognitive processes.
This focus is useful because it provides:
Clear concepts.
Testable predictions.
Explanations of dieting failure.
Possible practical applications.
However, it may neglect biological, social and environmental influences.
The boundary model partly addresses this limitation because it includes physiological hunger and satiation. It is therefore broader than restraint theory alone.
This evaluation can be developed through levels of explanation [Holism and reductionism].
Psychological determinism
These explanations may suggest that eating behaviour is determined by:
Dietary rules.
Beliefs about success and failure.
Previous restraint.
Social and cognitive influences.
This may underestimate the person’s ability to respond differently after a dietary lapse.
However, the explanation does not necessarily remove all personal agency. A person might learn to replace rigid, all-or-nothing rules with a more flexible response.
This debate connects with choice and determining influences [Free will and determinism].
Practical applications
A strength of psychological explanations is that they suggest ways of improving the success of dietary change.
If rigid restraint increases disinhibition, it may be useful to:
Avoid treating individual foods as completely forbidden.
Avoid viewing one lapse as total failure.
Recognise all-or-nothing thinking.
Develop more flexible forms of dietary control.
Return to planned behaviour after a lapse rather than abandoning restraint entirely.
These implications give the explanation practical value.
However, a strategy based only on cognition may be insufficient if biological vulnerability or the wider environment also contributes strongly.
Stigma and blame
Psychological explanations may be interpreted as blaming the person for obesity.
For example, focusing on failed restraint could suggest that the person:
Lacks self-control.
Chooses to overeat.
Is responsible for ineffective dieting.
This interpretation would be too simplistic.
Restraint theory proposes that rigid efforts at control may unintentionally increase overeating. It therefore challenges the assumption that successful weight regulation simply requires greater willpower.
A balanced account should recognise psychological processes without assigning moral blame.
Overall evaluation
Restraint theory explains how deliberate restriction can have the paradoxical effect of increasing consumption. Disinhibition explains why breaking one dietary rule may lead to the temporary abandonment of control. The boundary model provides the broadest account because it places these cognitive processes between biological hunger and satiation limits.
However, these explanations do not fully account for why obesity originally develops, why only some restrained eaters become disinhibited or how genetic and neural factors contribute. Psychological explanations are therefore most convincing as one part of an interactionist account.
Planning an extended response
For a question on psychological explanations of obesity, organise your answer around the assessment objectives.
Knowledge and understanding
Explain:
Restrained eating.
Cognitive dietary rules.
The paradoxical effect.
Disinhibition.
The “what the hell” effect.
Hunger and satiation boundaries.
The zone of biological indifference.
The self-imposed diet boundary.
How crossing the diet boundary may lead to overeating.
Application
Use separate details from the scenario.
For each detail:
Identify the dietary rule.
Name the relevant concept.
Explain the psychological mechanism.
Link it to increased intake or obesity.
Evaluation
Develop points such as:
Evidence for paradoxical eating.
The restraint-disinhibition cycle.
Difficulty explaining the original cause.
Individual differences.
Practical applications.
Cause-and-effect problems.
Comparison with biological explanations.
Reductionism and determinism.
Stigma and blame.
The boundary model’s integration of biological and psychological mechanisms.
Key Words 🔑
Key word | Student-friendly definition | How it may be used in an exam |
Psychological explanation | An account based on thoughts, beliefs or patterns of behaviour | Use it as the overall category for restraint, disinhibition and the boundary model |
Restraint | Deliberately regulating or restricting food consumption | Identify a strict diet or self-imposed eating rule in a scenario |
Restrained eater | A person who attempts to control food intake using conscious rules | Explain why eating may be governed by cognition rather than hunger |
Restraint theory | The explanation that deliberate dietary restriction can sometimes increase later eating | Use it to explain the paradoxical effects of dieting |
Cognitive control | Regulation of behaviour through thoughts and rules | Explain how the person attempts to override hunger |
Paradoxical effect | An outcome which is opposite to the intended result | Explain how trying to eat less may lead to eating more |
Disinhibition | Loss of restraint resulting in unrestrained eating | Apply it when a person abandons dietary control |
“What the hell” effect | The reaction in which breaking one rule is treated as complete dietary failure | Explain the transition from a small lapse to extensive eating |
Boundary model | A model combining biological hunger and satiation with cognitive restraint and disinhibition | Describe how biological and psychological factors interact |
Hunger boundary | The lower biological point beyond which hunger motivates eating | Explain when biological need initiates food intake |
Satiation boundary | The upper biological point beyond which fullness stops eating | Explain when physiological signals end food intake |
Zone of biological indifference | The area between hunger and satiation in which eating is strongly affected by cognitive and social factors | Explain why people may eat without intense hunger |
Diet boundary | A self-imposed cognitive limit on how much a restrained eater believes they may consume | Identify the rule that is crossed before disinhibition |
Preoccupation | Persistent attention to or thoughts about something | Explain how food restriction may make forbidden food more salient |
Yo-yo dieting | A repeated pattern of losing and regaining weight | Link repeated restraint and disinhibition over time |
Psychological determinism | The view that behaviour is governed by psychological processes or experiences | Evaluate how far the explanation allows personal choice |
Psychological reductionism | Explaining a complex outcome using a limited number of mental or behavioural processes | Evaluate whether biological and social influences are neglected |
Hints from the Examiner Reports 💡
Examiner hint: Keep linking the model to obesity. In the 2025 examination, many students accurately described the boundary model, but answers in which reference to obesity was largely absent tended to remain in the middle mark bands.
Examiner hint: Do not let description dominate an evaluation question. The 2025 report found that boundary-model responses were often rich in description but less successful in evaluation.
Examiner hint: Explain how the concepts work together. Successful students recognised that the boundary model integrates restraint and disinhibition rather than treating them as unrelated explanations.
Examiner hint: Use evidence to develop an argument. The 2025 report noted that students without evidence tended to produce less convincing evaluation points.
Examiner hint: Learn the terminology precisely. In 2023, some students confused restraint with boundary in a question requiring the correct psychological term.
Examiner hint: In an applied answer, use the details that show a sequence. Look for strict restriction, preoccupation with food, a broken rule, disinhibited eating and subsequent weight regain.
Examiner hint: For evaluate, focus entirely on strengths, limitations, evidence and comparisons. A question asking only for evaluation does not reward a lengthy description of the theory.
Examiner hint: Specialist vocabulary must be explained rather than dropped into the answer. State which boundary is crossed and why this leads to disinhibition.
Common Mistakes ⚠️
Mistake: Saying restraint means not eating anything.
Why this is incorrect:Restraint means deliberately regulating food consumption. A restrained eater may still eat, but according to self-imposed rules.
How to improve:Refer to conscious limits concerning the amount, type or timing of food.
Mistake: Assuming that all restrained eating is unsuccessful.
Why this is incorrect:Restraint theory proposes that restriction can have a paradoxical effect in some circumstances. It does not claim that every person who restricts food will overeat.
How to improve:Use cautious phrases such as “may lead to disinhibition” or “can increase the risk of overeating”.
Mistake: Defining disinhibition as being hungry.
Why this is incorrect:Disinhibition is the loss of cognitive restraint. Hunger is a biological motivation to eat.
How to improve:Explain that disinhibition occurs when dietary control is abandoned.
Mistake: Saying that one food automatically causes overeating.
Why this is incorrect:The psychological interpretation of the lapse is important. The person decides that the diet has failed.
How to improve:Include the judgement that the dietary rule has been broken and further restraint is pointless.
Mistake: Confusing the diet boundary with the hunger boundary.
Why this is incorrect:The diet boundary is a self-imposed psychological rule. The hunger boundary is a biological limit.
How to improve:Classify each boundary as cognitive or biological before explaining it.
Mistake: Saying that the zone of biological indifference means the person does not care about food.
Why this is incorrect:The term means that biological mechanisms do not strongly compel the person either to start or stop eating.
How to improve:Explain that cognitive and social factors have greater influence within the zone.
Mistake: Saying that satiation and restraint are the same.
Why this is incorrect:Satiation is a biological stopping process. Restraint is deliberate cognitive control.
How to improve:State whether eating stops because of fullness or because of a self-imposed rule.
Mistake: Describing the boundary model without linking it to obesity.
Why this is incorrect:The question requires an explanation of how crossing the diet boundary may increase food intake and contribute to obesity.
How to improve:End the explanation with the behavioural consequence and its possible effect on weight.
Mistake: Giving only generic evaluation.
Why this is incorrect:Statements such as “the theory is reductionist” are undeveloped unless their effect is explained.
How to improve:State what the explanation neglects and why this limits its ability to account for obesity.
Mistake: Treating biological explanations as completely incompatible.
Why this is incorrect:The boundary model itself incorporates biological hunger and satiation.
How to improve:Explain that psychological rules operate within biologically regulated limits.
Mistake: Blaming the person for lacking willpower.
Why this is incorrect:Restraint theory suggests that attempts at strict control can unintentionally increase overeating.
How to improve:Discuss the cognitive process without making moral judgements about the individual.
Exam-Style Questions ✍️
Question 1
Which of the following best describes disinhibition?
A. Biological hunger caused by an energy deficitB. Deliberate regulation of food intakeC. Loss of restraint followed by unrestrained eatingD. The upper boundary at which eating stops
[1 mark]
Question 2
Define restraint in the context of eating behaviour.
[2 marks]
Question 3
Explain why restrained eating may have a paradoxical effect.
[4 marks]
Question 4
Explain the difference between the hunger boundary and the diet boundary.
[4 marks]
Question 5
Luca has decided that he must never eat crisps. At a party, he eats a handful and immediately thinks, “The diet is ruined now.” He then continues eating until he feels extremely full.
Use psychological explanations of obesity to explain Luca’s behaviour.
[6 marks]
Question 6
Explain one limitation of restraint theory as an explanation for obesity.
[4 marks]
Question 7
Describe and evaluate the boundary model explanation for obesity.
[8 marks]
Question 8
Imani follows a strict eating plan and stops each meal after consuming the amount specified by the plan, even when she remains hungry. One evening, she eats more than her plan permits. She decides to restart the plan the following morning and spends the rest of the evening eating foods she normally forbids. This pattern has occurred several times, and Imani frequently regains the weight she has lost.
Discuss psychological explanations of obesity. Refer to Imani in your answer.
[16 marks]
Answers and mark scheme
Question 1
Answer: C
Disinhibition is the loss of dietary restraint followed by unrestrained eating.
[1 mark]
Question 2
Award up to two marks:
Restraint is the deliberate regulation or restriction of food consumption.
It involves using conscious rules to control what, when or how much a person eats.
[2 marks]
Question 3
Award up to four marks:
A person deliberately restricts food in order to reduce intake.
Restriction may increase preoccupation with food or make forbidden foods more salient.
If a dietary rule is broken, the person may abandon restraint.
Disinhibited eating may mean the person consumes more than they would have without the original restriction.
The answer must explain why the outcome is opposite to the intended effect.
[4 marks]
Question 4
Award up to four marks:
The hunger boundary is a biological limit.
Crossing it produces hunger and motivates eating.
The diet boundary is a self-imposed psychological limit.
It represents how much the restrained eater believes they are permitted to consume.
A comparison must distinguish biological regulation from cognitive control.
[4 marks]
Question 5
Award one mark for each clear application, up to six marks:
Luca’s rule that he must never eat crisps demonstrates restraint.
The rule creates a self-imposed diet boundary.
Eating a handful means that the diet boundary has been crossed.
Thinking that the diet is ruined demonstrates the “what the hell” effect.
Continuing to eat shows disinhibition.
Eating until extremely full suggests that consumption continues towards the satiation boundary.
Credit other developed applications using appropriate terminology.
[6 marks]
Question 6
Award marks as follows:
One mark for identifying a relevant limitation.
Up to three further marks for developing its effect on the explanation.
Possible answer:
Restraint theory does not fully explain individual differences. Many people regulate their food intake without becoming disinhibited or developing obesity. This means that restraint alone cannot be sufficient, and additional biological, cognitive or environmental factors may determine whether a dietary lapse leads to overeating.
Other relevant limitations include:
It may explain dieting failure rather than the original development of obesity.
Restraint may be a response to previous weight gain.
Evidence may not establish cause and effect.
The explanation may neglect genetic and neural influences.
[4 marks]
Question 7
Indicative content may include:
Knowledge
The model incorporates restraint and disinhibition.
Eating is regulated by hunger and satiation boundaries.
Between them is the zone of biological indifference.
Cognitive and social factors influence eating within this zone.
Restrained eaters create a self-imposed diet boundary.
Crossing this boundary can lead to disinhibition.
Eating may then continue until the satiation boundary is reached.
Evaluation
The model combines psychological and physiological mechanisms.
It explains how restraint and disinhibition form a cycle.
It recognises cognitive and social influences on eating.
Boundaries may be difficult to measure objectively.
Not all restrained eaters become disinhibited.
It may explain maintenance or dieting failure better than original causation.
Comparison with genetic and neural explanations.
Practical implications for flexible rather than rigid dietary rules.
Issues of reductionism, determinism and blame.
For the highest marks, evaluation must be developed and the answer must remain focused on obesity.
[8 marks]
Question 8
Indicative content may include:
Knowledge and understanding
Restraint involves deliberate cognitive regulation of food intake.
Restriction may produce a paradoxical increase in eating.
Disinhibition is the loss of restraint.
Breaking a diet boundary may produce a “what the hell” response.
The boundary model includes hunger and satiation boundaries.
The zone of biological indifference lies between them.
Restrained eaters place a cognitive diet boundary inside this zone.
Once the diet boundary is crossed, eating may continue towards satiation.
Application to Imani
Imani’s strict plan demonstrates cognitive restraint.
Stopping while still hungry shows that the diet rule overrides biological hunger.
The amount specified by the plan acts as her diet boundary.
Eating more than permitted crosses this boundary.
Deciding to restart the next morning suggests that she views the current day’s diet as failed.
Eating normally forbidden foods demonstrates disinhibition.
The repeated cycle is consistent with restraint followed by disinhibition.
Regaining weight shows how the cycle may contribute to obesity or unsuccessful weight regulation.
Evaluation
The scenario demonstrates the explanatory value of restraint and disinhibition.
The boundary model integrates cognitive control with biological hunger and satiation.
Not all restrained eaters respond to a lapse in this way.
The explanation may account for weight regain better than the original cause of obesity.
Restraint may have begun because of existing weight concerns, creating a cause-and-effect problem.
Genetic or neural vulnerability may also influence Imani’s eating.
The model may have useful applications by challenging all-or-nothing dietary rules.
Psychological explanations may be reductionist if wider influences are ignored.
They may risk blaming the individual.
An interactionist explanation may provide a fuller account.
A high-level answer will be accurate, organised and focused. It will apply several separate details from the scenario and develop its evaluation rather than listing brief points.
[16 marks]
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