Psychological explanations for obesity, including restraint theory, disinhibition and the boundary model.

RESTRAINT THEORY

Restraint theory provides a psychological perspective on the paradoxical increase in weight and obesity as a result of attempts to restrict food intake. Developed by Peter Herman and Deborah Mack in 1975, this theory posits that the very act of dieting and self-imposed eating restrictions can lead to an increased preoccupation with food, overeating, and subsequent weight gain. Below are evaluations of this theory, considering its strengths, weaknesses, and implications for understanding and addressing obesity.

Strengths of Restraint Theory

• Explains Paradoxical Overeating: Restraint theory effectively accounts for why people who attempt to diet strictly might end up overeating. It highlights the psychological impacts of dieting, such as increased food preoccupation and the breakdown of physiological hunger cues.

• Emphasises Psychological Factors: This theory underscores the importance of cognitive and emotional factors in eating behaviour, moving beyond simplistic models of obesity that focus solely on energy intake and expenditure.

• Research Support: Numerous studies have demonstrated that restrained eaters are more likely to experience episodes of overeating than unrestrained eaters. This supports the theory's premise that restraint can lead to the disinhibition of eating behaviours.

Weaknesses of Restraint Theory

• Not Universally Applicable: Restraint theory may not apply to all individuals equally. Some people successfully lose weight and maintain their weight loss through dietary restraint without experiencing the rebound effect of overeating.

• Causality Issues: While restraint theory suggests that dietary restraint leads to overeating, it's not clear whether individuals who are prone to overeating are more likely to engage in dietary restraint in the first place. This makes it difficult to establish a clear cause-and-effect relationship.

• Does Not Account for Biological Factors: The theory largely ignores the role of biological and genetic factors in obesity. For a comprehensive understanding of obesity, it's crucial to consider these alongside psychological aspects.

• Overlooks Environmental Influences: Restraint theory does not fully address how environmental factors, such as the availability of high-calorie foods and societal norms around eating, may contribute to the challenges of dietary restraint.

Implications for Treatment

Understanding the dynamics described by restraint theory has important implications for treating obesity. It suggests that interventions should focus on restricting calorie intake and improving individuals' relationships with food. Cognitive-behavioral approaches that aim to modify unhealthy eating patterns, improve self-regulation, and address psychological factors associated with overeating may offer more sustainable outcomes. Additionally, promoting intuitive eating practices, where individuals learn to respond to natural hunger and satiety cues, may help counteract the adverse effects associated with dietary restraint.

In conclusion, while restraint theory offers valuable insights into the complexities of dieting and its potentially counterproductive outcomes, it is essential to integrate these insights with a broader understanding of obesity that includes biological, environmental, and societal factors.

THE BOUNDARY MODEL OF DIETARY RESTRAINT

The Boundary Model, developed by Herman and Polivy in 1984, offers a nuanced explanation for the paradoxical relationship between dieting and overeating. This model suggests that human food intake is regulated within a spectrum, with physiological hunger and fullness anchoring the extremes. At these ends, our eating behaviour is primarily influenced by biological cues: we eat when energy levels are low, and we stop eating when we've consumed sufficient energy, experiencing a sense of fullness.

Zone of Biological Indifference:

Central to this model is the concept of the "zone of biological indifference." Within this zone, an individual is neither explicitly hungry nor full. Eating behaviours are less about biological needs and more about psychological, cultural, and social influences. This area represents the daily, non-urgent decisions about food that are influenced by factors such as social eating, cultural norms, and personal preferences.

Dieters vs. Non-Dieters:

This zone of biological indifference is significantly broader for dieters or restrained eaters. They are prone to feeling hungry sooner and require more to feel satiated. Moreover, Herman and Polivy introduced the idea of a cognitively determined "diet boundary." This boundary is self-imposed by dieters based on what they believe they should eat to lose weight, typically set lower than their natural satiation threshold.

The "What the Hell" Effect:

This model's critical point of interest is when dieters exceed their self-imposed diet boundary. Crossing this limit triggers the "what the hell" effect—a psychological response in which the individual, having already surpassed their dietary limit, continues to eat until they reach satiation or even beyond. This effect explains why dieters might overeat or binge eat after a minor dietary infraction.

Beyond the Boundary: Psychological and Social Factors:

The Boundary Model's strength is its acknowledgement of the psychological and social dimensions influencing dietary behaviour. It highlights how dieters navigate between their biological cues and the cognitive boundaries shaped by societal expectations and personal weight loss goals. This dynamic is further complicated by the myriad of external cues dieters face, from food advertisements to social gatherings centred around meals.

Implications for Understanding Diet Failure:

The model illuminates why dieting, especially restrictive, often fails long-term. It underscores the importance of addressing the psychological aspects of eating. Successful weight management strategies should consider the complex interplay between our biological needs, cognitive boundaries, and the broader cultural context.

By offering a comprehensive view of the factors influencing dietary behaviour, the Boundary Model provides valuable insights into the challenges of dieting and offers a framework for developing more effective and psychologically informed approaches to weight management.

Research by Herman and Mack (1975): Testing the Boundary Model

The study aimed to validate the Boundary Model by comparing the eating behaviours of restrained eaters (dieters) and non-restrained eaters (non-dieters) after consuming varying amounts of a preload (milkshake).

Methodology: Participants were divided into three groups in an independent design setup:

• Group 1 received one milkshake (single preload).

• Group 2 received two milkshakes (double preload).

• Group 3 received no milkshakes (no preload).

Subsequently, all participants were offered three tubs of ice cream under the guise of a taste test. The real measure, however, was the quantity of ice cream consumed (the dependent variable).

Finally, participants completed a questionnaire to determine their dieting status.

Results: Dieters (restrained eaters) responded counterintuitively: the more milkshakes they consumed (increased preload), the more ice cream they ate. This finding supports the "what the hell" effect, suggesting that once dieters surpass their cognitive boundary, they tend to overeat significantly.

Conversely, non-dieter ice cream consumption decreased with an increased preload, aligning with physiological cues of fullness.

Conclusion:

This research underlines a critical psychological barrier to successful dieting: the cognitive boundaries that dieters set for themselves can, paradoxically, lead to overeating when breached. The study highlights the complexity of human eating behaviours and suggests that understanding and modifying psychological responses to self-imposed dietary limits could be key to addressing dieting challenges.

Disinhibition, as a psychological construct, offers a compelling explanation for behaviours contributing to obesity. It delineates how overeating, rapid eating and recurring dieting failures may emerge from the weakening or removing internal controls under specific conditions. This concept is particularly relevant in understanding the complexities of eating behaviours and their impact on weight gain and body mass index (BMI).

THE DISINHIBITION MODEL

Understanding Disinhibition:

Disinhibition is characterized by the loss of restraint over eating behaviours, making an individual prone to overeating in the presence of palatable foods or during emotional distress. This state results in a diminished response to satiation cues, leading to increased vulnerability to overeating. Studies, including those by Bellisle et al. (2004), have demonstrated a strong correlation between disinhibition, adult weight gain, and BMI, highlighting its significance in obesity.

Types of Disinhibition:

Bond et al. (2001) categorize disinhibition into three distinct types, each contributing differently to overeating behaviors:

1. Habitual Disinhibition: This form is related to the routine overeating triggered by everyday circumstances. It's considered a significant predictor of weight gain due to the constant exposure to overeating triggers in a typical Western food environment.

2. Emotional Disinhibition: This involves overeating in response to emotional states such as anxiety or depression. Emotional eating represents a coping mechanism for managing negative emotions, albeit one that can contribute to unhealthy weight gain.

3. Situational Disinhibition: This occurs in response to specific external cues, often during social events. While influential, its less frequent occurrence than habitual disinhibition means it contributes less to the overall risk of obesity.

Hays and Roberts (2008) emphasize the importance of habitual disinhibition, referring to it as "opportunistic eating" due to the abundance of daily opportunities for overeating in modern societies. Bryant et al. (2008) support this view but note that situational and emotional disinhibition, while less frequent, still play roles in the development of obesity.

Evaluating the Explanation:

The psychological explanation of disinhibition provides valuable insights into the behavioural aspects of obesity. It acknowledges the complex interplay between internal psychological states and external environmental factors in shaping eating behaviours. However, this explanation also invites considerations of individual differences in susceptibility to disinhibition and the effectiveness of interventions to enhance self-regulation and coping mechanisms.

Conclusion:

Disinhibition as a psychological explanation for obesity underscores the need for a multifaceted approach to addressing obesity, which considers not only dietary and physical activity interventions but also strategies for managing emotional well-being and environmental triggers. Recognizing the roles of habitual, emotional, and situational disinhibition in overeating can guide the development of more comprehensive and effective obesity prevention and treatment programs.

EVALUATION

Ethical Considerations and Methodological Limitations of Herman and Mack's Study

The study's ethical considerations revolve around deception and the potential lack of fully informed consent. The deception was employed to prevent demand characteristics from influencing the participants' behaviour, a common practice in psychological research to ensure the validity of findings. However, this raises ethical questions about participants' autonomy and right to make fully informed decisions about their participation. While debriefing is critical to mitigate the ethical implications of deception, offering participants a comprehensive explanation of the study's true nature and purpose afterwards doesn't entirely negate the ethical dilemma posed by not obtaining fully informed consent initially.

The ethical question of whether the ends justify the means depends on evaluating potential harm against the study's scientific value. If participants were not psychologically or physically harmed and were debriefed adequately, the ethical breach might be considered justifiable. However, this assessment requires careful consideration of the study's contributions to understanding dietary behaviours and whether similar insights could have been achieved through less ethically contentious means.

Methodological Limitations:

1. Timing of Questionnaires: Administering questionnaires on dieting behaviour post hoc introduces potential biases. Participants' responses might be influenced by their awareness of being observed, affecting the accuracy of the self-reported data. Ideally, these questionnaires should be administered before the experiment to avoid biases and better classify participants as dieters or non-dieters from the outset.

2. Study Sample and Distribution of Dieters: With only 15 participants per condition and the distribution of dieters to non-dieters unknown until after the experiment, the study faces significant limitations in representativeness and statistical power. This limitation restricts the generalizability of the findings and the ability to make robust statistical inferences.

3. Lack of Controls: The absence of controls for factors such as previous eating disorders, level of physical activity, and weight complicates the interpretation of the results. These variables can significantly influence eating behaviour and should be accounted for in the study design.

4. Generalisability: The study's findings may not be generalizable beyond the specific demographic of participants, particularly regarding cultural differences and gender.

5. Participant Preferences: Assuming all participants would respond similarly to ice cream overlooks individual differences in food preferences, potentially introducing variability in the data that is not accounted for by the study's design.

6. The All or Nothing Theory and Its Implications for Dieting

   The All or Nothing Theory presents a compelling framework for understanding the complexities and challenges associated with dieting by drawing parallels with quitting addictive behaviours like smoking or alcohol consumption. This theory suggests that for some individuals, completely stopping an addictive behaviour is more effective than attempting to reduce it gradually. The success observed in those who quit smoking or drinking "cold turkey" highlights the potential effectiveness of an absolute cessation approach.

   Applicability to Dieting:

   However, when it comes to dieting, the All or Nothing approach encounters a significant challenge: unlike smoking or drinking, eating is necessary for survival. The body requires a regular intake of nutrients for energy, making it impossible to "quit" eating. This fundamental difference may partly explain why many find cutting calories and restricting diet more difficult than quitting other addictive behaviours. The necessity to continue eating, but in a moderated and controlled manner, introduces a complexity absent in the cessation of non-essential habits.

   
   
   

Psychological explanations for obesity

Social and lifestyle explanations

 

Some authors have pointed to the rapid economic and social changes in modern society (Chou 2004), resulting in copious amounts of palatable high energy food being readily available while at the same time reducing physical daily demands to very low levels—coined as ‘the toxic food environment’(Horgen & Brownell, 2002).

Indeed, there has been a huge increase in the availability and consumption of fast food, soft drinks, ready-made meals, and snacks over the past few years. Take for example coffee shops like Star Bucks and Costa where a medium sized coffee with cream has half a day’s calorie requirements.

Fast foods generally have higher energy content (calories) often in the form of fats and refined carbohydrates and/or sugars and low nutritional content. While soft drinks are full of sugar. Portions have also increased in size (Anderson and butcher, 2006). Changes in food processing during the past 30 years, particularly the addition of sugar to a wide variety of foods that once never included sugar and the removal of fiber, both of which promote insulin production, have created an environment in which our foods are essentially addictive. A02: Not an experimental study only correlational. Although the fact that we eat more of the wrong foods does make biological sense when used with Taubes theory. Especially as people in collectivist societies may eat the same quantity of food but don’t put on as much weight as their diet is not so sugar based.

Lustig, A UCSF researcher, says “Our current Western food environment has become highly ‘insulinogenic,’”, as demonstrated by its increased energy density, high-fat content, high glycemic index, increased fructose composition, decreased fiber, and decreased dairy content. In particular, fructose (too much) and fiber (not enough) appear to be cornerstones of the obesity epidemic through their effects on insulin,” A02: Studies on non carbs support this idea as pps claim their appetite greatly reduces when not eating carbohydrates. See study in successful diet section.

A02: The fact that modern living conditions offer individuals ample opportunity to eat as much as they want, any time any place, is relevant to a discussion on obesity but it does not explain why people would engage in this type of behavior, knowing that it makes them fat in the short run and compromises their health in the long run.

A02 unless of course you combine psychological lifestyle explanations with ET and point out that we have not only been naturally selected to want fat, sugar and Carbohydrates but to overeat to excess.

 

Move from agricultural to industrial society Activity level affects body weight. Before the introduction of electric power and the gasoline engine, muscle power did most of the work. People were much more active and burned off lots of calories. So the meals they ate were enormous by modern standards. In modern "post-industrial" society, many people seek out some of the exercise that used to come naturally from everyday activities. They join health clubs, work out at home, or jog. But pretty much we are not exercising enough now to burn away what we eat.

In many parts of the world where obesity is not a problem, human muscle power is still the major source of work. In these places, the bosses who don't work physically may eat as many calories as do people who work hard physically, so naturally they likely to be overweight. Interestingly, the people who eat the least have intermediate activity levels.

 

A02: It is unclear whether reduced physical activity is a cause or a consequence of obesity but Psycho-social factors have been implicated with lack of exercise: This could be because of perceptions of competence, e.g., not being good at exercise and/or fear of displaying body in a public setting

Other reasons might be lack of opportunities for exercise or lack of need to exercise. E.g. using car and public transport + TV – Prentice & Jebb (1995)..

 

People with chronic weight problems may be suffering from a lack of self-confidence, low self-esteem and are self-conscious about their appearance.  That is another reason not to visit a gym or an exercise class.

 

A02: An increasing body of research reveals that exercise does next to nothing for you when it comes to losing weight. A great result for couch potatoes, yes, but also one that could have serious implications for the government's long-term health strategy. More and more research in both the UK and the US is emerging to show that exercise has a negligible impact on weight loss. That tri-weekly commitment to aerobics class? Almost worthless, as far as fitting into your bikini is concerned. The Mayo Clinic, a not-for-profit medical research establishment in the US, reports that, in general, studies "have demonstrated no or modest weight loss with exercise alone" and that "an exercise regimen… is unlikely to result in short-term weight loss beyond what is achieved with dietary change." From a practical perspective, then, exercise is never going to be an effective way of slimming, unless you have the training schedule – and the willpower – of an Olympic athlete. "It's simple maths," says Professor Paul Gately, of the Carnegie Weight Management institution in Leeds. "If you want to lose a pound of body fat, then that requires you to run from Leeds to Nottingham, but if you want to do it through diet, you just have to skip a meal for seven days."

 

The increase in television and computer games (face-book, play-station, Xbox, Wii, texting, DVD’s, sky, skpe, mobile phones) correlates with the increase in childhood obesity over the past twenty years. Early research suggests that each hour spent on technology increases levels of obesity by 2 percent (Dietz, 1985). Besides the lack of exercise, technology use (especially watching TV) is associated with more snack foods and exposure to food advertising. The food industry invests substantial sums of money into researching aspects of food that makes it more attractive, such as taste and colour. It has been very effective in using research into feeding behaviour to persuade us to eat food with high calorific intake and little nutritional value. A02: Obviously studies such as these are only correlational so cause and effect cannot be established. Give another reason if you can.

An experimental study published in the July 2009 issue of Health Psychology examines the hypothesis that exposure to food advertising during TV viewing may also contribute to obesity by triggering automatic snacking of available food. In the first experiment, elementary-school-age children watched a cartoon that contained either food advertising or advertising for other products and received a snack while watching. In a second experiment, adults watched a TV program that included food advertising that promoted snacking and/or fun product benefits, food advertising that promoted nutrition benefits, or no food advertising. The adults then tasted and evaluated a range of healthy to unhealthy snack foods in an apparently separate experiment.  The amount of snack foods consumed during and after advertising exposure was carefully measured. Results showed that children consumed 45% more when exposed to food advertising. Adults however, consumed more of both healthy and unhealthy snack foods following exposure to snack food advertising compared to the other conditions. In both experiments, food advertising increased consumption of products not in the presented advertisements, and these effects were not related to reported hunger or other conscious influences. The researchers concluded that the experiments demonstrate the power of food advertising to trigger automatic eating behaviors and can influence far more than brand preference alone A02: Much better research. Experimental, easy to draw cause and effect conclusions. Unethical though as these children may be affected by the advertising long term.

 

 “Food manufacturers take advantage of our evolutionary heritage, resulting in their making a great deal of money and in us spending money and becoming overweight and unhealthy. Moreover, the food industry is, very successful in exploiting visual food cues, which interfere with adequate monitoring of food consumption, making humans extremely vulnerable to overconsumption.”

 

Food manufacturers know how to use psychology to get your child to like their products. Corporate researchers learn to use the psychology of taste preferences to make your child crave their empty calorie junk foods.

Food manufacturers count on the fact that if parents feed their kids processed food, even if they do so only occasionally, the kids will crave it and ask for it more and more. Eventually, some parents will give up and feed their children a steady diet of processed, manufactured food, ensuring a steady income for the food manufacturer giants.

Here are some of the techniques that Big Food uses:

1) Sugar - Food manufacturers put sugar in most of their foods, even those that aren't desserts like spaghetti sauce or frozen meals. Human beings have a natural desire for sugar -- it signals calories and vitamin c, which were scarce in prehistoric times. The amount of sugar in manufactured foods is much higher than any foods that our prehistoric ancestors ever ate -- and produces an addictive response that can be as strong as cocaine.

2) Fat - Food manufacturers put vegetable oil in most of their foods. It's cheap and, like sugar, addictive in large quantities.

3) Salt - Salt is also addictive and hides the unpleasant flavor that a lot of processed food has. Food manufacturers know that if your child is given a high salt diet, she will learn to crave the salty taste.

4) Mild Taste - Processed food has very little taste. Manufacturers rely on the salty, sugary, fatty tastes to get your child addicted to their food. Processed foods have little real flavors, compared to the strong taste of real foods like oranges, spinach, or cauliflower. This means that children can eat the food over and over again and not get tired of it. Your child can eat her sugary cereal or granola bar every day, but would get tired of broccoli if you fed it to her every day.

5) Predictable Taste - Processed food tastes the same each time you eat it. One box of Oreos tastes the same as the next box. Your child gets used to the uniformity and starts to find the variation in natural foods like peaches or apples disgusting. In prehistoric times, if a food tasted different from usual, it usually meant it had gone bad. Food manufacturers know that if they corrupt this instinct by getting children used to food that is absolutely the same, the children won't go back to eating their parents' home-cooked meals, with its natural variability in taste.

6) Predictable Texture - Like taste, children have an instinct to avoid foods that have an unusual texture, especially mushy or slimy foods. Food manufacturers know that if they get kids used to the uniform crunchy, chewy, or creamy textures that factories can create so well, they won't like the complex and variable textures of a real meal.

7) Appearance - No parent can create foods of multi-colors, shaped like animals or stars. Children are very drawn to appearances, and food manufacturers know this.

8) Ads with Excitement, Fun - Most of us can remember wanting a toy that we saw on TV, only because the commercial was exciting. The same is true of food. Parents don't advertise their home-cooked meals. Food manufacturers do advertise their food, with bright colors, music, smiling faces, and excited "cool" kids. They use classical conditioning by pairing fun with the product. Operant conditioning like McDonalds by giving a present with a happy meal (although also classical) and social learning theory by making the role models in adverts appealing  so kids want to copy what they are eating.

9) Ads with People Eating - In addition to exciting ads, food manufacturers show people eating the food and enjoying it. Food manufacturers know that children have an instinct to eat the same food other people are eating. This instinct was beneficial in the days when many plants were poisonous -- children had to learn to eat the same wild plants that the adults around them were eating.

10) Packages - Children love packages. Young kids will ignore a birthday present in order to play with the box it came in. Manufacturers make their packages as colorful and fun as possible. Children will whine for a cereal or candy, just because they like the box it comes in.

 

 

‘The built environment’. Rightly or wrongly city life is seen as increasingly dangerous, either as a result of crime (paedophiles, mugging, rape, gangs) or traffic accidents). Children play less, walk less and travel more by car because of this. Parents don’t let their children have as much freedom.

 

The increase in the number of working parents means that there is little time for food preparation; parents being too tired to cook and thus more reliance on fast food. There is less time spent on organising activities with children.

 

A02

1.     Most women have worked throughout history and cross culturally (accept for the time when factory laws prohibited women from bringing their children to work. Thus the creation of the modern house wife was born. Most children experience both their parents being busy/working so this may not be relevant to a theory on obesity.

 

2.    The social and psychological changes in feeding behaviour and lifestyle outlined above provide a convincing account of the increase in childhood and adult obesity. The most convincing aspect is that it fits with what we already know about energy regulation (calories) in relation to feeding and body weight.

3.    However, the research is non-scientific and correlational only meaning we cannot draw conclusions about cause and effect. In this area it is impossible to separate all of the many extraneous variables and do controlled studies on the relationship for example TV viewing and obesity. So many other factors could be contributory (genes, metabolism, individual differences in shape and size, amount of exercise)

4.    Moreover, it would be unethical to manipulate viewing hours to observe the effects of obesity.  Therefore, we do not know which lifestyle explanation is the most influential in causing obesity, indeed if any are at all.

5.    Social and lifestyle theories cannot be the whole picture in that they see the cause of obesity as relating to cultural/sociological influences. They seem to ignore other explanations such as biological, evolutionary or psycho dynamic theories. Explanations should be eclectic and combine nurture and nature.

6.    Not culturally biased though as comparisons are made with collectivist societies. For example cultures that do not have abundant food are slim. Historical comparisons can also be used as it is only since the availability of fast foods that the west has become a fat nation.

7.    Obesity is probably best understood within the framework of the evolutionary approach, e.g., evolutionary theory and lifestyle. Lifestyle and social factors would not be maybe not be as influential if we were not naturally selected by evolutionary processes to be lazy, greedy and in love with refined Carbohydrates, fats and sugars.

8.    Individual differences. This theory suggests we are all greedy, lazy chubsters! There are many individuals who despite living in modern societies are fit and healthy and refrain from using technology and eating the wrong foods to excess. Therefore biology must come in to it.

9.    The government need to have more input into controlling: advertising, school dinners, encouraging sport, control of junk food etc. as obesity costs the country huge amounts in medical bills never mind the premature deaths that are caused by being morbidly fat.