The psychology of obesity Jane Ogden Professor of Health Psychology University of Surrey

Overview The causes of obesity The role of behaviour Obesity treatment Dietary interventions Medication Surgery What doesn’t work? What works? How can obesity be treated effectively?

Obesity Trends* Among U.S. Adults BRFSS, 1985 No Data <10% 10%–14% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1986 No Data <10% 10%–14% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1987 No Data <10% 10%–14% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1988 No Data <10% 10%–14% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1989 No Data <10% 10%–14% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1990 No Data <10% 10%–14% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1991 No Data <10% 10%–14% 15%–19% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1992 No Data <10% 10%–14% 15%–19% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1993 No Data <10% 10%–14% 15%–19% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1994 No Data <10% 10%–14% 15%–19% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1995 No Data <10% 10%–14% 15%–19% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1996 No Data <10% 10%–14% 15%–19% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1997 No Data <10% 10%–14% 15%–19% ≥20 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1998 No Data <10% 10%–14% 15%–19% ≥20 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 1999 No Data <10% 10%–14% 15%–19% ≥20 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 2000 No Data <10% 10%–14% 15%–19% ≥20 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Obesity Trends* Among U.S. Adults BRFSS, 2001 No Data <10% 10%–14% 15%–19% 20%–24% ≥25% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

(*BMI  30, or ~ 30 lbs overweight for 5’4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person) Obesity Trends* Among U.S. Adults BRFSS, 2002

Obesity Trends* Among U.S. Adults BRFSS, 2003 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person) No Data <10% 10%–14% 15%–19% 20%–24% ≥25%

Obesity Trends* Among U.S. Adults BRFSS, 2004 No Data <10% 10%–14% 15%–19% 20%–24% ≥25% (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)

Why this increase? Genetic theories One obese parent = 40% risk of obese child Two obese parents = 80% risk of obese child Twin / adoptee studies:66-70% of variance accounted for by genetics But…… Cannot explain changes over time Cannot explain migration data

Obesogenic environment Sedentary lifestyle Less manual labour More car use Town planning Remote controls Mobile phones More fast food Less cooking More eating out More snacking

A role for behaviour Physical activity Eating behaviour

Why do exercise? Habit Learning Childhood Attitudes Costs and benefits Peer norms Social norms ‘we like it’

Eating behaviour

Why do we eat what we eat? Hunger?

The meaning of food Emotional regulation Social interaction Habit

Why do we eat? Habit Learning Childhood Costs and benefits Peer norms Social norms ‘we like it’ ‘we try NOT to eat it’

Basically ….. We eat because at the time the benefits of eating out weigh the costs

Therefore…. Good evidence for genetic basis to obesity Cannot explain rapid increase Role for obesogenic environment Highlights role for behaviour Activity and eating Role of psychology Obesity treatment? Needs to address behaviour Needs to address psychology of behaviour What works / doesn’t work? / why?

Dietary interventions Traditional programmes: Eat less Lost weight but 99% regained weight Multidimensional packages: Lifestyles changes, cognitive restructuring, reasonable weights, nutritional information, self monitoring, relapse prevention, screening patients, follow ups 60% lose weight Up to 95% regain weight in longer term

Why don’t they work?

Dieting Trying to eat less But…. Most dieters show episodes of overeating The ‘what the hell’ effect

Why don’t dietary interventions work? Trying to change embedded habit Rebound back to old habit High effort Restriction takes away function Emotional regulation Social interaction AND imposes denial Creates preoccupation with food Lowers mood Exacerbates benefits of eating Offers no costs of eating

What can we learn? Behaviour is difficult to change Habits Function of food Social Emotional regulation Communication Benefits out weigh costs Dieting exacerbates benefits Denial

Alternatives?

Medication Orlistat (Xenical) Prevents fat absorption Causes unpleasant side effects Qualitative study The experience of taking Orlistat as a window into: Successful behaviour change (Ogden and Sidhu, 2006)

Causes of obesity Medical ‘I’m not a big eater, sometimes I don’t even want to eat but I just eat coz I have to eat coz I’m diabetic’ (Frances). Behavioural ‘I ate too much. I ate all the wrong foods. I did a static job….. And the bigger I got the more I ate. And that’s about it really. I used to eat a colossal amount…..it was bacon, eggs, sausages, chips… I used to eat loads and loads of meat. Beef, pork. I could eat two French sticks in one sitting’ (Matthew).

Experiences of side effects ‘I had near misses… I don’t break wind unless I’m sitting on the loo. It’s a fear thing – I have had situations where I’ve had to discard a pair of boxer shorts’ (David). ‘messy’, disgusting’, ‘horrible’, ‘unsafe’, ‘near misses’, ‘accidents’, ‘personal oil slick’.

Behaviour change? Showed behaviour change if ……… Behavioural model of causes Visual side effects act as an education

What can we learn? Drugs work by: Encouraging a behavioural model of obesity See diet as the cause Create match between cause and solution Create short term costs of overeating

Surgery Reduces stomach size Reduces food intake Can cause dramatic weight loss But has unpleasant side effects

Qualitative study In depth interviews 15 people who had had surgery (Ogden et al, 2005; 2006)

Role of food ‘I used to think about food all the time..before I got married I’d sit in bed reading recipe books thinking cor I fancy that…now I think that would be good and that wouldn’t’

Hunger ‘The most incredible thing that has happened is lack of appetite… the hunger pangs have gone… I’m sated when I eat’

Control over food ‘ ‘If someone or something didn’t stop me I would just continue. What the operation has done for me is that physically because my stomach is smaller I can only eat smaller meals…because I know I can’t I don’t’

What can we learn? Surgery works by… Reduces function of food Changes habit Emotional regulation Social interaction Provides short term costs to overeating Taking away control from individual Relies upon stomach size NOT denial

Therefore Obesity on the increase Obesogenic environment Behaviour Behaviour difficult to change Treatment alternatives Have psychological implications

How can we improve weight management?

Need to change behaviour Avoid … Avoid consequences of dieting Avoid denial Avoid making food more pleasurable Avoid exacerbating benefits of eating

To Do…. Acknowledge and address the psychology of obesity Address psychology of behaviour AND / OR change environment AND / take away control through surgery AND / OR offer surgery but support people through it