1. Why is behaviour change so difficult to achieve?
Dr Elisabeth Weichselbaum
Nutrition Scientist and Consultant
ewnutrition.net

3. Knowledge alone is not enough
Plenty of information about healthy diet and lifestyle
It is likely that many people are aware of ‘what they are supposed to eat’
Survey in UK
99% knew fruit and vegetables very or fairly important
94% said eating less salt was important
92% said limiting foods high in saturated fat was important
Awareness about healthy eating and lifestyle alone has not led to behaviour change
Perhaps the key to behaviour change lies in better understanding the mechanisms behind behaviour itself?
Food Standards Agency 2010

4. What factors influence behaviour?
Physical
Psychological
Includes knowledge & skills
Reflective processes
Automatic processes
Social
Physical
Michie et al. 2011, Implementation Science 6:42

5. Why is the healthier choice not always the easier choice?
Our intentions and plans can only influence behaviour if they generate sufficiently strong wants or needs at the relevant moment to overcome competing wants or needs.
Larger, less certain and more distant rewards (e.g. losing weight, stay healthy)
Environmental cues + power of immediate and certain pleasure (e.g. of eating chocolate)
vs.
Marteau 2011, BMJ 342: ; Atkins and Michie, Nutrition Bulletin 38:30-35 .

6. Human behaviour shaped by two systems (Dual Process model)
Reflective, goal oriented system
Driven by our values and intentions
Requires cognitive capacity or thinking space
Many traditional approaches to health promotion target this system, i.e. designed to alter beliefs and attitudes
Automatic, affective system
Requires little or no cognitive engagement
Driven by immediate feelings and triggered by environments
Strack and Deutsch 2004, Pers Soc Psychol Rev 8:

7. Beyond awareness
Adults typically make more than 200 food-related decisions per day…
…but are aware of 14.4 food-related decisions.
Most of our food-related decisions are beyond conscious awareness
This is for a good reason
Would you get much done if you questioned all of your 200+ food-related decisions?
Wansink and Sobal 2007, Env Behav 39:39-106; Chadwick et al. 2013, Nutrition Bulletin 35:36-42

8. Consumption norms
People very easily influenced when it comes to how much they eat
Plate size, package size, larger portions in restaurants, larger kitchen ware…
They all suggest a certain ‘norm’ or portion size
People underestimate this influence and believe they are immune to them
Wansink 2010, Psychology & Behavior 100:

9. Are we aware of influence?
4 Experiments, intervention:
A larger serving (double popcorn)
Same serving, but in larger package
Intervention groups consumed 32% more than control group
Only 8% thought they ate more than usual
73% thought they ate about the same
19% thought they ate less
Wansink 2010, Psychology & Behavior 100:

10. Are we aware of influence?
When told about the intervention and its effect
52% claimed they did not eat more
31% said if they did eat more it was because they were hungry
15% gave other reasons (special occasion, it was free)
Only 2% acknowledged it was because of the environmental cue
This means these determinants are not available for the processes of monitoring, reflection and goal-directed behaviour required for successful modification
Many people say “don’t know why they are so overweight since they hardly eat anything”
Could be explained by fact that many determinants of food choice are beyond conscious awareness
Wansink 2010, Psychology & Behavior 100:

11. The power of habit
Strength of habit has a strong influence on behaviour
Habit can even override taste (which itself strongly influences food choice)
Habitual behaviour is more dependent on environment and less under conscious control
Chadwick et al. 2013, Nutrition Bulletin 35:36-42;

12. The power of habit Fresh Stale Weak habit of eating popcorn in cinema
Strong habit of eating popcorn in cinema
Meeting room context
Cinema
Meeting room context
Cinema
Ate the similar amount of fresh and stale popcorn.
Ate less when presented with stale than with fresh popcorn.
Neal et al. 2011, Pers Soc Psychol Bull 37:

13. Nudging – a possible way to change behaviour
Nudging means to change physical or social environment to make a certain behaviour more likely
Mainly operates through the automatic, affective system
Marteau 2011, BMJ 342: ; Thaler and Sunstein: Nudge. Yale University Press 2008.

14. Does nudging work?
Nudging works, although currently often used to drive unhealthy eating behaviour
Limited evidence on nudges to encourage healthy behaviour
Cumulative nudges in a wide range of contexts may be required to be effective
Within enabling legislative and policy environments
Marteau 2011, BMJ 342:

15. Healthier choice does not equal healthy weight
People tend to think of foods as either ‘good’ or ‘bad’
Behave as though healthy foods have ‘halos’ – are perceived to be less likely to promote weight gain
Chernev 2011, J Cons Psych 21:

16. Which promotes more weight gain?
Students and adults were presented with a variety of ‘healthy’ and ‘unhealthy’ snack options +
vs.
Chocolate
569 kcal
47 kcal
Oakes 2005, Appetite 44: ; Oakes 2005, Food Quality and Preference 16:

17. + The Dieter’s Paradox OR 14% kJ
Chernev 2011, J Cons Psych 21:

18. Obesity is not a rational choice!
Conclusion
How can we influence behaviour that lies outside awareness?
Could nudging work?
How can we avoid stereotype thinking about food?
Obesity is not a rational choice!