Week 7

Environmental and Policy Factors and Obesity

Dr. Bonnie BeezholdAssistant Professor, NutritionBenedictine University

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

But does our ENVIRONMENT play a special role?

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

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

Industrialized agriculture and obesity http://www.jhsph.edu/research/centers-and-

institutes/johns-hopkins-center-for-a-livable-future/

The status quo > continued drive to fewer farms in the hands of small number of companies, subsidies for commodity crops (corn and soy), factory farms, cheap prices, and more processed foods

Farm bill (last revised 2007)

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

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

Sweetened beverage intake and the prevalence of obesity have risen over the same time period

Woodward-Lopez, Kao, Ritchie, 2011

Between 1977 and 2002, Americans on average increased their energy intake from soft drinks by 228 % and their energy intake from fruit drinks by 171 %. Soft drinks contribute more energy to the diet than any other single type of food or beverage; they are also the top source of liquid energy in the US.

Evidence of link between sweetened beverage intake and obesity The majority of observational studies (higher quality)

show that sweetened beverage intake is significantly associated with greater adiposity Only one study reported a negative association

2 RCTs showed that successful reduction of sweetened beverage intake reduced adiposity among children

4/6 trials showed weight gain among free-living adults who increased intake of sweetened beverages 2 trials failed to detect a significant impact on adiposity (lower

quality design)

Reid et al, 2007

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

When fat cells have enlargedand energy intake continues to exceed energy expenditure, fat cells divide, increasing in number again.

During growth,fat cells increasein number, parti-cularly in late childhood, early puberty.

When energy intakeexceeds expenditure,fat cells increase in size, capable of increasing by 20-fold.

With fat loss, the size of the fat cells shrinks, but not the number, and they tend to refill.

Childhood obesity and fat cell theory

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

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

Wang & Beydoun, 2011

The relative cumulative mean (±SEM) effect size on food intake for alcohol consumption, sleep deprivation, and television watching.

Chapman C D et al. Am J Clin Nutr 2012;96:492-497

Studies curtailing these factors have shown a decrease in food intake.

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

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

Socioeconomic factors

Built environment

Definition: 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

Phoenix, AZ

Sedentary behavior and 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

Hypothalamus releases CRF; anterior pituitary gland releases ACTH; adrenals release cortisol; many cells release cytokines

Cortisol stimulates lipoprotein lipase and inhibits hormone sensitive lipase leading to the storage of triglycerides and decreased mobilization of free fatty acids. Glucocorticoids also enhance neuropeptide Y concentration, increasing appetite.

Cortisol profiles on stress and control sessions across sample

Epel et al, 2001

Raw mean calories consumed by reactivity group on stress and control days.

Cortisol reactivity profiles of high and low reactors during stress session

Raw mean calories consumed by reactivity group on stress and control days

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).

Rutters et al, 2009

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.

Energy intake from sweet foods and total energy intake were significantly higher in the stress condition compared to the control condition, and differences in energy intake stronger in subjects with high disinhibition scores.

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

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).

In this study, reward signaling and reward sensitivity were significantly lower under stress, coinciding with increased energy intake from food choice for more crispiness and fullness of taste. The changes in putamen activation may reflect specifically decreased reward prediction

Death row nutrition. Curious conclusions of last meals. Wansink et al, 2012, Appetite J

Findings: (1) the average last meal is calorically rich (2756 calories) and proportionally averages 2.5 times the daily recommended servings of protein and fat, (2) the most frequent requests are also calorie dense: meat (83.9%), fried food (67.9%), desserts (66.3%), and soft drinks (60.0%), and (3) 39.9% requested branded foods or beverages. These findings are consistent with studies of how food is used to mediate feelings of stress and distress.

Other environmental factors

Do we have a “myopic emphasis on the Big Two”? (Ten

Putative Contributors to the Obesity Epidemic, McAllister et al, 2009); They explored basic, epidemiologic, experimental studies Examples:

Restaurant dining – While more cals are consumed, they are largely compensated for (Anderson & Matsa 2008)

PA – Some studies report sport participation is up (Salmon et al 2008); PE classes have no appreciable impact (Cawley et al, 2007)

Vending machines – No evidence of contribution to obesity (Faith et al, 2007)

We need more research!

Infections –human adenoviruses such as Ad-36 can alter metabolism; may impact adipogenesis, leptin, etc

Reproductive fitness – mild-to-moderate obesity may have positive effect on fecundity, thereby passing on genetic predisposition

Assortative mating and ‘floor effects’ – phenotypical mates pass on genetic susceptibility; evidence that the entire BMI distribution shifted to right; increases in underweight prevalence has not paralleled obesity

Ambient temperature – increased usage of climate control results in more time inside, less EE allocated towards maintaining body temperature (Rowe et al 1982; van Hanswijck de Jonge et al 2002)

Other environmental factors

McAllister et al, 2009

Other environmental factors

Sleep debt – amount of sleep in population has decreased over past 40 yrs; can change ghrelin secretion, NPY levels independent of body weight (Barcelo et al, 2004); U shape of BMI vs hrs sleep mirrors mortality risk vs hr sleep

Endocrine disrupters – wide exposure to chemicals that may interfere with hormone signaling, homeostatic regulation; PBDE, BPA, lipophilic pesticides DDT, atrazine, organo-chlorines (Stahlhut et al, 2007)

Pharmaceuticals – evidence that psychotropics, anti-hypertensives, beta-blockers, antidiabetic agents may contribute to weight gain

McAllister et al, 2009