The psychology of obesity

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

2. 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?

3. The rise in obesity

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

21. Obesity Trends* Among U.S. AdultsBRFSS, 2002 (*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%

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

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

24. 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

25. 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

26. A role for behaviour • Physical activity • Eating behaviour

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

29. Eating behaviour

31. Why do we eat what we eat? • Hunger?

32. The meaning of food • Emotional regulation • Social interaction • Habit

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

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

35. 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?

36. 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

37. Why don’t they work?

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

39. 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

40. 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

41. Alternatives?...............

42. 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)

43. 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).

44. 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’.

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

46. 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

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

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

49. 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’

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