Overview
This lecture frames obesity as a chronic, complex, multifactorial disease rather than a matter of personal responsibility. It covers the WHO definition and New Zealand prevalence data, then works through weight stigma and bias (its definition, sources, and how it is experienced), the psychosocial consequences of obesity in childhood and adulthood, a systems/determinants view of how obesity develops and is maintained (including feedback loops between stigma and weight gain), and finishes with modern treatment considerations, including GLP-1 agonists (Wegovy) and practical clinical communication strategies.
What is obesity
- WHO definition: obesity is a chronic, complex, and multifactorial disease characterised by abnormal or excessive fat accumulation that presents a risk to health.
- Three key words in the definition: chronic, complex, multifactorial.
- Obesity in Aotearoa New Zealand (2024/25 NZ Health Survey):
- ~1 in 3 adults (34.2%) live with obesity.
- ~1 in 9 children (11.7%) live with obesity.
- Rates are higher among Māori, Pacific peoples, and people in areas of higher socioeconomic deprivation.
- NZ has one of the highest adult obesity rates in the OECD.
Weight stigma and bias
- Weight stigma is defined as the inclination to form unreasonable judgements based on a person’s weight, e.g. characterising people with obesity as lazy, unmotivated, incompetent, noncompliant, sloppy, or lacking self-discipline/willpower.
- Causal framing spectrum presented as three positions, with the middle position endorsed as balanced:
- “It’s entirely personal responsibility” (rejected).
- “Behaviour matters enormously, but behaviour is never context-free” (the balanced view).
- “Individuals have no agency” (rejected).
- Examples of weight stigma given:
- Media: language and images attributing obesity to personal responsibility (e.g. a broadcaster suggesting taping over people’s mouths).
- Overt discrimination: derogatory remarks made publicly (e.g. a runner insulting participants at a fitness challenge).
- Internalised stigma: a person’s own self-critical, shame-laden self-talk about their body and eating.
- More subtle discrimination: limited availability/range/sizing of fashionable clothing; being observed making food choices in public; discomfort using public transport; fat jokes and reluctance to use the word “fat”; loaded language around food and exercise (“healthy,” “clean,” “junk,” “cheat day,” “treats”).
- Implicit bias: Project Implicit IAT data (over 1.1 million web respondents, April 2004-December 2015) on automatic weight-bias preference:
- Strong preference for thin over fat: 31%
- Moderate preference for thin over fat: 28%
- Slight preference for thin over fat: 16%
- Little to no automatic preference: 15%
- Slight preference for fat over thin: 5%
- Moderate preference for fat over thin: 3%
- Strong preference for fat over thin: 1%
- Weight stigma is commonly experienced from: peers, school, health providers, community, media.
- Health providers are often reluctant to raise weight, citing their own communication skills and concern about the impact on the doctor-patient relationship. Illustrative quotes from providers: parents feel “affronted” and judged when a child’s weight is raised; some providers hold a “defeatist attitude” that discussing it “isn’t going to make any difference”; providers question “who are we to judge.”
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Psychosocial consequences
- Childhood, related to stigma:
- Children aged 6-13 with obesity are 4-8 times more likely to be bullied at school than normal-weight peers.
- Teachers show weight-related stereotypes, e.g. lower expectations for social, reasoning, physical, and cooperation skills in students with obesity than normal-weight students.
- Children rate siblings as the most frequent source of negative weight-related talk, followed by parents.
- Discrimination is experienced by 13-32% of youth and 44-57% of adults.
- Childhood, broader outcomes:
- Lower quality of life.
- Weight-based stigmatisation.
- Possible link to self-esteem and depression, mediated by body dissatisfaction (transcript marks this as an open/uncertain association, denoted with a question mark on the slide).
- Why consider obesity in childhood: longitudinal associations with chronic health conditions, persistence or worsening of unhealthy weight, mental disorders (depression/pāpōuri and anxiety/manawapā), and systemic (health and economic) costs.
- Adulthood:
- NZ data show higher rates of depression/pāpōuri and anxiety/manawapā disorders in people with BMI >30, with no corresponding increase in substance use disorders/ngā waranga (Scott et al., 2008, Journal of Psychosomatic Research).
- Pooled data from World Mental Health surveys across 13 countries show the same pattern, with a stronger association in women (Scott et al., 2008, International Journal of Obesity).
Viewing obesity through a systems lens
- Life course and social determinants model (Shuluf et al., 2007): nested layers of influence from innermost to outermost — genes/biological factors, family/whānau, physical environment, informal society (friends, peers, neighbours), formal society (educational institutions, community organisations, law and order, social support, government agencies), wider social environment (cultures, policies). These layers connect across generations (inter-generational cycle), within a single lifetime (lifetime cycle), and through broader social/political/cultural change over time (social, political and cultural cycle).
- Two complementary indigenous holistic health frameworks were shown alongside this model: the Pacific Fonofale model (a house with pillars for physical, spiritual, mental, and other dimensions, resting on a family foundation, with culture as the roof, and time/environment/context as surrounding elements) and the Māori Hauora model (depicted as a waka/canoe with sails, representing holistic health).
Some text labels on the Fonofale and Hauora diagrams were too small/low-resolution to transcribe with confidence.
- Six categories of determinants feed into “unhealthy weight status”: prenatal, behavioural, neighbourhood, social, family systems, cognitive.
- Case study (Jamie, 9-year-old female, 93rd percentile for height/weight, poorly controlled asthma) used to apply the determinants framework: family beliefs (“big-boned,” not perceived as different), socioeconomic constraints on healthy eating/exercise, social difficulties (trouble making friends, teasing during netball, withdrawal to solitary indoor activities), neighbourhood factors (dense housing, no nearby supermarket, nearby fast food outlets, nearest green space far away).
- Contributing factors by category (example sub-factors):
- Family systems: beliefs/attributions, routines, diet, resources, history, relationships.
- Neighbourhood/environment: mobility, resources.
- Social: stigma, victimisation, relationship difficulties/isolation.
- Prenatal/antenatal: maternal weight status, weight gain during pregnancy, rapid weight gain in early infancy.
- Behavioural: nutrition, physical activity, sedentary time, sleep.
- Cognitive: recognition, myths/understanding, attributions/self-talk, inhibitory control/self-regulation, sensitivity to reward.
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- Example pathway - dual process model: poor inhibitory/impulse control plus food responsivity (sensitivity to short-term vs long-term reward) combine to drive weight gain via unhealthy food choices (quantity or quality).
- Example pathway - adversity route: residential mobility and financial stress contribute to early experiences of adversity, which lead to a stress response, disrupted sleep, and poor nutrition, which in turn lead to unhealthy weight status.
- Example pathway - expanded multi-branch model: early experiences of adversity and frequent relocations/financial stress feed into three intermediate factors: negative beliefs and attributions; stress response, disrupted sleep, and poor nutrition; and poor health engagement/poor recognition. These lead respectively to low self-efficacy; poor social support, stigma, and bullying; and low physical activity, high sedentary time, and social withdrawal. These converge on mental health and body dissatisfaction, which combines with genetics, maternal weight, and prenatal environment to produce unhealthy weight status.
- Predictors and outcomes as bidirectional feedback loops:
- Loop 1: high BMI leads to stigma and teasing, which leads to social withdrawal, reduced physical activity, increased sedentary time, and comfort eating, which leads to further weight gain, which feeds back into high BMI.
- Loop 2: body dissatisfaction leads to unhealthy weight control behaviours, which leads to further weight gain and high BMI, which feeds back into body dissatisfaction.
- These loops illustrate that stigma, BMI, and weight gain act as both predictors and outcomes of one another.
Modern treatment
- Wegovy (a GLP-1 receptor agonist): reduces appetite and slows gastric emptying, producing significant weight loss outcomes.
- Psychological questions raised: if weight loss becomes purely pharmacological, what happens to personal-responsibility narratives around obesity, and does the drug reduce stigma or reinforce the idea that a person “should just take the drug”?
- Ethical questions raised: who gets access (cost, PHARMAC restrictions, when patients should start), what happens when patients stop the medication, and identity questions such as “was it me or the medication?”
- Clinical strategies - comprehensive approach:
- Respond to the psychological dimensions of obesity (social, emotional, cognitive, behavioural, family, systemic).
- Attend to comorbid physical and mental health conditions.
- Assess mental health indicators in patients with obesity, and consider obesity risk in patients with mental health challenges.
- Reflect on one’s own bias and the impact of stigma sources on patients.
- Balance educating/motivating patients with sensitivity and a non-judgemental approach.
- Clinical strategies - communication: many doctors avoid raising weight for fear of upsetting patients, but studies show patients are mostly open to discussing weight and appreciate help. General principles:
- Be aware of your own attitudes.
- Ensure respect for patients as individuals comes across.
- Approach the topic cautiously and sensitively, preferably within an established clinical relationship; do not avoid it altogether.
- Make clear you are not judging the patient; normalise the difficulty of weight loss/maintenance “in today’s world,” shifting blame from the individual to the obesogenic environment.
- Empower patients: indicate what they as individuals can do to counter the obesogenic environment, and express belief in their ability to do so.
- More specific strategies:
- Ask permission before discussing weight.
- Ask for preferred terminology (weight and BMI are often preferred terms).
- Use person-first language (“person with obesity” rather than “obese person”).
- Reframe language: “excuses” becomes “strategies to minimise triggers”; “discipline or self-control” becomes “ways to practice healthy habits as part of daily routines”; “don’t overindulge” becomes “ways to feel satisfied and avoid feeling deprived.”
Summary
Obesity is complex, multifactorial, chronic, and socially shaped. Good care requires curiosity, humility, empathy, and systems thinking.
Self-test
- State the WHO definition of obesity and the three key words it turns on.
- What proportion of NZ adults and children live with obesity, and which groups have higher rates?
- Define weight stigma, and describe the “balanced” position on personal responsibility presented in the lecture, contrasted with the two extremes it sits between.
- Give one example each of overt discrimination, internalised stigma, and subtle discrimination toward people with obesity.
- From the Project Implicit IAT data described, what proportion of respondents showed any degree of automatic preference for thin over fat people?
- List the settings in which weight stigma is commonly experienced, and describe why health providers are often reluctant to raise weight with patients.
- Describe the psychosocial consequences of obesity in childhood, including the bullying statistic and the role of body dissatisfaction.
- Compare the mental health outcomes associated with obesity in NZ and pooled international data for adulthood, including which population shows a stronger association and what does not increase.
- List the six categories of determinants feeding into unhealthy weight status, with one example factor from each.
- Describe the dual process model pathway to weight gain via unhealthy food choices.
- Describe the two feedback loops that make stigma/BMI and body dissatisfaction/weight gain “both predictors and outcomes.”
- What is Wegovy, how does it work, and what psychological and ethical questions does its use raise?
- List the five general principles for discussing weight with a patient sensitively.
- A patient with obesity comes in for an unrelated issue. Using the specific communication strategies from the lecture, describe how you would raise the topic of weight if clinically relevant.
Answers
Reveal answers
- Obesity is a chronic, complex, and multifactorial disease characterised by abnormal or excessive fat accumulation that presents a risk to health. The three key words are chronic, complex, and multifactorial.
- Approximately 34.2% of NZ adults (about 1 in 3) and 11.7% of NZ children (about 1 in 9) live with obesity; rates are higher among Māori, Pacific peoples, and people in areas of higher socioeconomic deprivation.
- Weight stigma is the inclination to form unreasonable judgements based on a person’s weight (e.g. viewing people with obesity as lazy or lacking self-discipline). The balanced position is that behaviour matters enormously but is never context-free, sitting between the extremes that obesity is entirely personal responsibility and that individuals have no agency at all.
- Overt discrimination: a runner publicly insulting participants with obesity at a fitness challenge. Internalised stigma: a person’s own harsh self-talk describing themselves in shaming terms after a setback. Subtle discrimination: limited range/sizing of fashionable clothing, or discomfort around others observing one’s food choices in public.
- 75% (31% strong + 28% moderate + 16% slight preference for thin over fat).
- Commonly experienced in: peers, school, health providers, community, media. Providers are reluctant because of concerns about their own communication skills and the potential impact on the doctor-patient relationship, sometimes reflecting a defeatist attitude or discomfort with appearing judgemental.
- Children with obesity are 4-8 times more likely to be bullied at school (ages 6-13); teachers hold lower expectations of them; siblings are the most frequent source of negative weight-related talk; 13-32% of youth experience discrimination. Broader outcomes include lower quality of life and possibly lower self-esteem/depression, mediated by body dissatisfaction.
- Both NZ data and pooled World Mental Health survey data (13 countries) show higher rates of depression and anxiety in adults with BMI >30, with the association stronger in women; substance use disorders do not show a corresponding increase.
- Prenatal (e.g. maternal weight status), behavioural (e.g. physical activity), neighbourhood (e.g. mobility), social (e.g. stigma), family systems (e.g. routines), cognitive (e.g. sensitivity to reward).
- Poor inhibitory/impulse control combines with food responsivity (sensitivity to short-term over long-term reward) to drive weight gain via unhealthy food choices, in quantity or quality.
- Loop 1: high BMI leads to stigma and teasing, which drives social withdrawal, reduced activity, more sedentary time, and comfort eating, causing further weight gain and higher BMI. Loop 2: body dissatisfaction drives unhealthy weight control behaviours, causing further weight gain and higher BMI, which feeds back into body dissatisfaction. Each factor is therefore both a cause and a consequence of the others.
- Wegovy is a GLP-1 receptor agonist that reduces appetite and slows gastric emptying, producing significant weight loss. Psychologically, it raises questions about what happens to personal-responsibility narratives once weight loss is pharmacological, and whether it reduces or reinforces stigma. Ethically, it raises questions about access (cost, PHARMAC restrictions, timing of starting), what happens when medication stops, and patient identity (“was it me or the medication?”).
- Be aware of your own attitudes; ensure respect for the patient comes across; approach the topic cautiously and sensitively within an established relationship rather than avoiding it; make clear you are not judging, normalising the difficulty of weight management; empower the patient by affirming their ability to act against the obesogenic environment.
- Ask the patient’s permission to discuss weight; ask their preferred terminology (weight/BMI are often preferred); use person-first language (“person with obesity”); avoid framing things as excuses or lack of discipline, instead discussing strategies to minimise triggers and ways to build healthy habits into daily routines without feeling deprived.