Behaviour and Obesity

Behaviour change is seen as central to the prevention, management and treatment of obesity for individuals, groups and entire populations. Reversing the trend of increasing obesity rates over the past decades requires an integrated evidence‐based approach that recognises behaviours are influenced by a combination of biological, psychological and social factors. However, while individual behaviour change is extremely important, the interventions need to be drawn from a comprehensive, coherent framework with a clear link to an overarching model of behaviour. Improving the design and implementation of evidence‐based practice depends on successful behaviour change interventions. This requires an appropriate method for defining interventions and linking them to an analysis of the targeted behaviour. Michie et al. coordinated a suite of five studies involving consensus methods, randomised control trials and analysis of qualitative data. The three‐year project involved 400 researchers, practitioners and policymakers from several countries who produced a “taxonomy” of 93 behaviour change techniques with clear labels, definitions and examples. At the centre of the proposed new framework is a ‘behaviour system’ involving three essential conditions: capability, opportunity and motivation (labelled as the ‘COM‐B system’, see Figure 11.1).

This forms the hub of a ‘behaviour change wheel’ (BCW) around which the nine intervention functions are positioned, aimed at addressing deficits in one or more of these conditions; around these seven categories of policy are placed, which could enable those interventions to take place. A detailed specification of interventions is important for basic and applied behavioural science. The UK Medical Research Council (MRC) guidance for developing and evaluating complex interventions advocates this approach. In addition, the ‘behavioural change wheel’ was used reliably by the United Kingdom National Institute of Health and Clinical Excellence’s guidance on reducing obesity (see Figure 11.2).

These studies enabled Public Health England to issue guidance for delivering and commissioning ‘Adult Weight Management Clinics’ (2017) providing relevant, evidence‐based behaviour change techniques recommended for inclusion in weight management services for weight loss and weight‐loss maintenance. Examples of defined behavioural change interventions (that can be used by trained generic community teams for weight management) would be self‐monitoring, goal setting, problem solving, behavioural instruction, social support and behavioural feedback. Specialist weight assessment and management services employ specific behavioural change interventions including the following strategies of behavioural interventions for adults as appropriate: self‐monitoring of behaviour and progress, stimulus control, goal setting, slowing rate of eating, assertiveness, cognitive restructuring (modifying thoughts), reinforcement of changes and relapse prevention. These are all evidence‐based behavioural change interventions used frequently by psychologists. A key psychological consideration is the individual’s ‘readiness for weight management’. Motivational Interviewing has been widely adopted as a practical model highly applicable to weight management. This psychological model enables rapid and reliable measures of self‐efficacy and salience (or importance) of any health behaviour. This combines the extensive psychological literature on self‐efficacy and Motivational Interviewing, which together are core predictive constructs that shape behaviour.

Experienced specialist weight management community teams are able to deliver comprehensive, multidimensional cognitive behavioural packages combining evidence‐based behavioural components (self‐monitoring, cognitive restructuring and relapse prevention) along with physical exercise and nutritional information. Skea et al. reported a qualitative systematic review of 33 studies of weight management programmes for adults with severe obesity. A very wide range of tools and theories of behavioural change were employed in the programmes, and they examined the components of lifestyle programmes that were valued by participants. They concluded that programmes that were perceived to be novel or exciting would be valued by participants as was in‐person group‐based programmes that would aid continuing engagement. A review of specialist weight management programme in the UK by Alkharaiji et al. found 5% weight loss was reachable at early stages of the intervention which would have significant clinical benefits. In the very large NHS Glasgow UK Weight Management Service, the key issues were non‐attendance and attrition and the lack of data to account for the reasons for this. However, patients who scored caseness for severe anxiety (HADS > 11) or depression (HADS > 14) and were offered additional psychological input achieved similar weight‐loss outcomes to those with less anxiety and depression. Teixeira et al. reported a systematic review of the psychological mediators of successful outcomes in lifestyle change obesity programmes. They found some evidence in 35 studies that higher autonomous motivation, self‐efficacy and self‐regulation skills emerged as the best predictors of beneficial weight and physical activity outcomes.

The Emotions and Obesity

The exact process by which emotions affect eating behaviour emerges as one of the central unresolved questions in the field of emotional eating. The concept of emotional regulation refers to the efforts people make to influence the experience and expression of their emotions. Emotional eating has been defined as a ‘tendency to overeat in response to negative emotions such anxiety or irritability’. This behaviour is of interest because emotional eating has been consistently associated with overweight and obesity. However, there is a paradoxical relationship to stress. Many studies have demonstrated the varying results of the effects of stress on eating. In many samples, half the subjects ate more and half ate less in response to stress. This contradictory relationship between stress and eating is well recognised and has been called the ‘stress‐eating paradox’.

This was clarified by further studies that demonstrated that the negative emotion itself may not be responsible for overeating but rather the lack of adaptive emotion regulation strategies available to regulate negative affect. The five‐way model developed by Macht provides a good example of how intense emotions affect eating. Maladaptive strategies to regulate emotion like suppression result in a decreased food intake. Restrained eating used by dieters impairs their cognitive eating controls and frequently binge eat in response to restraint. Another maladaptive strategy, clearly seen in the model, is ‘emotional eating’, which is used to downregulate emotions and is associated with an increased intake of sweet, high fat foods (Figure 11.3).

In response to this common finding in weight management services, the psychological models most frequently used are Cognitive Behaviour Therapy, Interpersonal Psychotherapy, Acceptance and Commitment Therapy (NICE Guideline, CG90). An empirical overview of the usefulness of adjunctive psychosocial treatments suggested positive effects on eating behaviour and psychosocial functioning.

However, psychological distress has a more pervasive source in weight stigma which is associated with a range of negative outcomes, including disordered eating. The discrimination, prejudice and negative stereotyping of the overweight and obese appear to have increased over time. Experiences of weight stigma are associated with a range of negative behavioural and psychological consequences, such as binge eating, emotional eating and psychological distress. Furthermore, many studies have shown that when weight bias is internalised, there is a tendency to accept self‐blame for negative stereotypes. This internalisation is associated with increased psychological distress, depression, anxiety and disordered eating behaviours. In a large Australian study, O’Brien et al. found compelling evidence for the adverse health consequences of weight stigma and suggested that social policymakers are encouraged to develop anti‐stigma policies for school, work and health settings. The conceptual model that guided the study is shown in Figure 11.4.

Since obesity prevalence is high throughout the world, there is a pervasive and strong culture of weight stigma and is even more prevalent than the discrimination based on race. Surprisingly, it is present in healthcare settings with adverse consequence for health outcomes. This has serious implications for the management and treatment of obese patients who face referral barriers since the negative stereotyping is likely to place blame entirely within the individual. The drivers of stigma are primarily based around a misunderstanding of the complex causes of obesity, with people attributing weight gain entirely to personal responsibility and failing to grasp the complex mix of genetics, obesogenic environment and biological factors that drive it.

Internalised weight bias has been found to mediate the adverse psychological consequences of weight stigma. The individual carries a vulnerability to depression, low self‐esteem, poor body image, disordered eating, psychological distress and avoidance in relationships. The problem of weight stigma is so universal, causing much harm to affected individuals, that a ‘joint international consensus statement for ending stigma of obesity’ has been published with recommendations to eliminate weight bias. The statement is designed to inform health professionals, policymakers and the public in order to facilitate a new public narrative about obesity based on modern scientific knowledge. In a review of the role of weight stigma, it was found to be particularly pervasive in healthcare settings where a large sample of physicians (N = 2284) showed a strong explicit and implicit anti‐fat bias and concluded that weight stigma is likely to drive weight gain and poor health.

A more recent theoretical model of obesity incorporating biological, psychosocial and environmental factors has been proposed by Marks. This suggests that the over‐consumption of high‐calorific, low‐nutrient and low‐satiating foods, combined with a stressful environment, is the origin of weight gain. Once that weight gain occurs, an individual experiences body dissatisfaction and negative affect leading to continued over‐consumption over a prolonged period. This dysfunctional state leaves individuals unable to control weight gain and subsequently forms a vicious ‘Circle of Discontent’. This model (see Figure 11.5) highlights the important role of body image along its pathway, particularly how general negative affect (depression and low self‐esteem) is associated with body dissatisfaction, patterns of consumption and directly with weight gain. Although comfort eating may result in temporary reduction in distressed mood, the weight gain that follows may cause a dysphoric mood due to an inability to control one’s distress and subsequent feelings of guilt may reactivate the cycle, leading to a continuous pattern of using food to cope with emotions.

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