Eating behaviors are complex

1. Lecture 5Environmental and Policy Factors and ObesityDr. Bonnie Beezhold Assistant Professor, Nutrition Benedictine University

2. Eating behaviors are complex There is a complex interplay of physiological, psychological, social, and genetic factors that influence meal timing, quantity of food intake, food preference, and food selection

3. Why do we have an obesity crisis? • What factors are relevant to the high prevalence and global nature of the crisis that developed over the last 100 years? • Genetics don’t change in a century!

4. Food system changes • Increased supply of cheap, palatable, energy-dense foods • Improved distribution systems for convenience and accessibility of these foods • More persuasive and pervasive food marketing Swinburn et al, 2011

5. For more information on agricultural policy and obesity, go to: http://aphg.jhsph.edu/index.cfm?event=browse.subject&subjectID=31

6. http://www.huffingtonpost.com/2011/11/09/map-every-mcdonalds-us_n_1084045.htmlhttp://www.huffingtonpost.com/2011/11/09/map-every-mcdonalds-us_n_1084045.html

8. Fat cell theory • Fat cell numbers may increase more quickly in children, leading to life-long tendency toward obesity (hyperplastic)

10. Nutrition Reviews, May2009 Supplement, Vol. 67, pS36-S39

11. Consumption factors • Of 21 food and beverages investigated, red meat and fruit were negative associated with a difference in waist circumference • Snack foods were positively associated with the difference in WC Halkjær et al, 2009

12. Pima Indians • The Pima Indians living in AZ consume a high-fat diet (50% fat) provided by govt surplus commodities rather than their traditional low-fat diet (15% fat). They are also much more sedentary than when they were as farmers. Lifestyle changes have resulted in an epidemic of obesity and diabetes over the last 50 years. • The Pima Indians who live in the Sierra Madre mountains of Northern Mexico, who have been isolated from Western influences, eat a traditional Pima diet and are physically active as farmers and sawmill workers. The Pimas of Mexico have a much lower incidence of obesity and diabetes than their kin in AZ. Pratley, 1998; Ravussin et al, 1994

13. Other eating trends related to obesity • Not enough fruits and vegetables (per guidelines) • Population fat intakes exceed recommendations by at least 10% • The sharp increase in portion size over the last few decades has distorted our perceptions • Increase in plate (10" to 12"), bowl, cup sizes, utensils • There is group disparity of affordability and accessibility of better food and more physical activity Wang & Beydoun, 2011

14. Socioeconomic factors • Low SES and minority groups are disproportionately affected at all ages • Diets of low SES households provide cheap, concentrated energy from fat, sugar, cereals, potatoes, fatty meats; they eat negligible whole grains, fish, vegs, fruit • Low-income consumers are more likely to be frequent users of fast-food, more likely to live in areas with less physical access to healthier foods Drewnowski, 2007

15. Socioeconomic factors • Neighborhood residents who have better access to supermarkets and limited access to convenience stores tend to have healthier diets and lower levels of obesity (Larson, 2009) • There are significant disparities in the availability of food • Black and Hispanic neighborhoods had 50% and 70% fewer chain supermarkets compared with white and non-Hispanic neighborhoods, respectively • Shopping at supermarkets vs independent grocers is associated with more frequent F&V intake

16. Sedentary behavior - labor-saving devices • Telecommuting • Internet / e-mail • Food deliveries • Pay per view movies • Computer games • Moving sidewalks • Garage door openers • Personal computers • Cellular phones • Escalators/elevators • Drive-in windows • Intercoms • Remote controls • Vacuum robots • ETC

17. Built environment • All of the physical parts of where we live, work, and play • Built environment can both “facilitate and hinder physical activity and healthful eating” (IOM, 2002) • Evidence of the association between the built environment and obesity is still preliminary Ding & Gebel, 2011

18. Stress, the HPA axis and obesity • Adaptive response to stress: • Hypothalamus releases CRF • Anterior pituitary gland releases ACTH • Adrenals release cortisol which increases energy via gluconeogenesis • Cytokines are released by many cells, increased by catecholamines and inhibited by glucocorticoids Feedback control eventually signals hypothalamus to stop producing CRF

19. Raw mean calories consumed by reactivity group on stress and control days. Cortisol profiles on stress and control sessions across sample Raw mean calories consumed by reactivity group on stress and control days Cortisol reactivity profiles of high and low reactors during stress session Epel et al, 2001

20. Changes in state anxiety scores (means) over time in the stress and control condition in all subjects (n = 129). *P < 0.05 for differences in time in the stress compared to the control condition (ANOVA repeated measures). Differences in means of energy intake of snack foods (kJ) during stress and control condition in all subjects (n = 129). *P < 0.05 for stress vs. control condition, t-test. Rutters et al, 2009

21. Fasted subjects came twice to randomly complete either a rest or stress condition. Per session, two functional MRI scans were made, wherein the subjects chose the subsequent meal (food images). Putamen activation was decreased postprandially (AUC = -1.2%BOLD s, P<0.05). Sagittal (a), coronal (b) and transversal (c) sections, showing the GLM contrast rest condition versus stress condition. Significant activation in present in the putamen (22, 4, -3 and -23, 11, 4) and the orbitofrontal cortex (-8, 28, -6, P<0.05 FDR corrected). Born et al, 2010