The World Is Round
Secular trends in the prevalence of general and abdominal obesity among Chinese adults, 1993-2009
B. Xi et al.
Obesity Reviews, forthcoming
Abstract:
The objective of this study is to examine the trends in body mass index (BMI), waist circumference (WC) and prevalence of overweight (BMI 25-27.49 kg m-2), general obesity (BMI ≥ 27.5 kg m-2) and abdominal obesity (WC ≥ 90 cm for men and ≥80 cm for women) among Chinese adults from 1993 to 2009. Data were obtained from the China Health and Nutrition Survey, which was conducted from 1993 to 2009 and included a total of 52,621 Chinese adults. During the period of 1993-2009, mean BMI values increased by 1.6 kg m-2 among men and 0.8 kg m-2 among women; mean WC values increased by 7.0 cm among men and 4.7 cm among women. The prevalence of overweight increased from 8.0 to 17.1% among men (P < 0.001) and from 10.7 to 14.4% among women (P < 0.001); the prevalence of general obesity increased from 2.9 to 11.4% among men (P < 0.001) and from 5.0 to 10.1% among women (P < 0.001); the prevalence of abdominal obesity increased from 8.5 to 27.8% among men (P < 0.001) and from 27.8 to 45.9% among women (P < 0.001). Similar significant trends were observed in nearly all age groups and regions for both men and women. The prevalence of overweight, general obesity and abdominal obesity among Chinese adults has increased greatly during the past 17 years.
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Impatience, Incentives, and Obesity
Charles Courtemanche, Garth Heutel & Patrick McAlvanah
NBER Working Paper, October 2011
Abstract:
This paper explores the relationship between time preferences, economic incentives, and body mass index (BMI). Using data from the 2006 National Longitudinal Survey of Youth, we first show that greater impatience increases BMI and the likelihood of obesity even after controlling for demographic, human capital, occupational, and financial characteristics as well as risk preference. Next, we provide evidence of an interaction effect between time preference and food prices, with cheaper food leading to the largest weight gains among those exhibiting the most impatience. The interaction of changing economic incentives with heterogeneous discounting may help explain why increases in BMI have been concentrated amongst the right tail of the distribution, where the health consequences are especially severe. Lastly, we model time-inconsistent preferences by computing individuals' quasi-hyperbolic discounting parameters (beta and delta). Both long-run patience (delta) and present-bias (beta) predict BMI, suggesting obesity is partly attributable to rational intertemporal tradeoffs but also partly to time inconsistency.
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Don't Mind Meat? The Denial of Mind to Animals Used for Human Consumption
Brock Bastian et al.
Personality and Social Psychology Bulletin, forthcoming
Abstract:
Many people like eating meat, but most are reluctant to harm things that have minds. The current three studies show that this dissonance motivates people to deny minds to animals. Study 1 demonstrates that animals considered appropriate for human consumption are ascribed diminished mental capacities. Study 2 shows that meat eaters are motivated to deny minds to food animals when they are reminded of the link between meat and animal suffering. Finally, Study 3 provides direct support for our dissonance hypothesis, showing that expectations regarding the immediate consumption of meat increase mind denial. Moreover, this mind denial in turn reduces negative affect associated with dissonance. The findings highlight the role of dissonance reduction in facilitating the practice of meat eating and protecting cultural commitments.
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Richard Dunn, Joseph Sharkey & Scott Horel
Economics & Human Biology, forthcoming
Abstract:
Rural areas of the United States tend to have higher obesity rates than urban areas, particularly in regions with high proportions of non-white residents. This paper analyzes the effect of fast-food availability on the level of fast-food consumption and obesity risk among both white and non-white residents of central Texas. Potential endogeneity of fast-food availability is addressed through instrumental variables regression using distance to the nearest major highway as an instrument. We find that non-whites tend to exhibit higher obesity rates, greater access to fast-food establishments and higher consumption of fast-food meals compared to their white counterparts. In addition, we found that whites and non-whites respond differently to the availability of fast-food in rural environments. Greater availability is not associated with either greater consumption of fast-food meals or a higher obesity risk among the sample of whites. In contrast, greater availability of fast-food is positively associated with both the number of meals consumed for non-white rural residents and their obesity. While our results are robust to specification, the effect of availability on weight outcomes is notably weaker when indirectly calculated from the implied relationship between consumption and caloric intake. This highlights the importance of directly examining the proposed mechanism through which an environmental factor influences weight outcomes.
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Chris Herbst & Erdal Tekin
NBER Working Paper, September 2011
Abstract:
This paper examines the impact of the spatial accessibility of public human services agencies on the likelihood of receiving a child care subsidy among disadvantaged mothers with young children. In particular, we collect data on the location of virtually every human services agency in the U.S. and use this information to calculate the approximate distance that families must travel from home in order to reach the nearest office that administers the subsidy application process. Using data from the Kindergarten cohort of the Early Childhood Longitudinal Study (ECLS-K), our results indicate that an increase in the distance to a public human services agency reduces the likelihood that a family receives a child care subsidy. Specifically, we estimate an elasticity of subsidy receipt with respect to distance of -0.13. The final section of the paper provides an empirical application in which we use variation in families' travel distance to identify the causal effect of child care subsidies on children's weight outcomes. Our instrumental variables estimates suggest that subsidized child care leads to sizeable increases in the prevalence of overweight and obesity among low-income children.
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Janneke Giesen et al.
Appetite, February 2012, Pages 6-10
Abstract:
The present study investigated the effect of taxing high-energy dense products and subsidizing low-energy dense products on changes in calorie consumption. More specifically, we hypothesized that ‘more impulsive' individuals were less influenced by such pricing strategies compared to ‘less impulsive' individuals. Contrary to our hypothesis, results showed that ‘more impulsive' individuals adjusted their calorie consumption with regard to price changes whereas ‘less impulsive' participants were less influenced by price changes. Furthermore, taxing high-energy dense products was more successful in reducing calorie consumption than subsidizing low-energy dense products.
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Allocation of household responsibilities influences change in dietary behavior
Candace Nelson et al.
Social Science & Medicine, November 2011, Pages 1517-1524
Abstract:
This study was undertaken to understand dietary behavior as situated within the household, an important social context that serves to either inhibit or promote a healthy diet. Data were collected as part of a worksite-based health behavior intervention trial that took place between 1999 and 2003 in small manufacturing businesses in New England, USA. The subjects were a cohort of 790 male and female workers who participated in the intervention trial and responded to both the baseline and the 18-month follow-up surveys. Regression models were built to determine whether proportion of household responsibility predicted daily fruit and vegetable consumption and weekly red meat consumption at 18-months. The results indicate that participants who were responsible for earning most or all of the money to support the household ate more servings of fruits and vegetables per day at 18-month follow-up than those without this responsibility. Further, those responsible for earning about half ate fewer servings of red meat than those responsible for earning most or all of the money to support the household. The results for red meat consumption differed by sex, such that responsibility for more than half or less than half of the money to support the household had different effects for men and women. The results of this study demonstrate that the distribution of household responsibilities can be an important factor in determining the effectiveness of a worksite-based health behavior intervention and that these effects can be different for women versus men.
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The Influence of Body Weight on Social Network Ties among Adolescents
Mir Ali, Aliaksandr Amialchuk & John Rizzo
Economics & Human Biology, forthcoming
Abstract:
Evidence of negative stereotypes, prejudice and discrimination towards obese individuals has been widely documented. However, the effect of a larger body size on social network ties or friendship formations is less well understood. In this paper, we explore the extent to which higher body weight results in social marginalization of adolescents. Using data from a nationally-representative sample of adolescents, we estimate endogeneity-corrected models including school-level fixed effects that account for bi-directionality and unobserved confounders to ascertain the effect of body weight on social network ties. We find that obese adolescents have fewer friends and are less socially integrated than their non-obese counterparts. We also find that such penalties in friendship networks are present among whites but not African-Americans or Hispanics, with the largest effect among white females. These results are robust to common environmental influences at the school-level and to controls for preferences, risk attitudes, low self-esteem and objective measures of physical attractiveness.
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Homophily and Contagion as Explanations for Weight Similarities Among Adolescent Friends
Kayla de la Haye et al.
Journal of Adolescent Health, October 2011, Pages 421-427
Purpose: To determine whether weight-based similarities among adolescent friends result from social influence processes, after controlling for the role of weight on friendship selection and other confounding influences.
Methods: Four waves of data were collected from a grade 8 cohort of adolescents (N = 156, mean age = 13.6 years) over their initial 2 years of high school. At each wave, participants reported on their friendship relations with grade-mates and had their height and weight measured by researchers to calculate their body mass index (BMI). Newly developed stochastic actor-oriented models for social networks were used to simultaneously assess the role of weight on adolescents' friendship choices, and the effect of friends' BMIs on changes in adolescent BMI.
Results: Adolescents' BMIs were not significantly predicted by the BMI of their friends over the 16 months of this study. Similarities in the weights of friends were found to be driven predominantly by friendship selection, whereby adolescents, particularly those who were not overweight, preferred to initiate friendships with peers whose weight status (overweight/nonoverweight) was the same as their own.
Conclusions: Weight-based similarities among friends were largely explained by the marginalization of overweight adolescents by their peers, rather than by the "contagion" of excess weight among friends. These findings highlight the importance of adequately modeling friendship selection processes when estimating social influence effects on adiposity.
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Heather Francis & Richard Stevenson
Behavioral Neuroscience, forthcoming
Abstract:
Regulation of energy intake depends in part on both memory for prior food intake and internal signals of hunger and satiety. These functions are both mediated by the hippocampus, a brain structure that animal studies have shown to be impaired after maintenance on high fat and refined sugar (HFS) diets. Study 1, using a cross-sectional design, revealed that self-reported HFS diet was associated with poorer performance on hippocampal sensitive memory tasks but not other neuropsychological control measures. Study 2 replicated this finding in two groups selected to differ in HFS intake, additionally showing that this effect is specific to hippocampal functioning and does not extend to measures of prefrontal cortex function. Furthermore, in a laboratory-based test of food intake, the HFS rich diet groups were less accurate in recalling what they had previously eaten and evidenced reduced sensitivity to internal signals of hunger and satiety, relative to a group consuming less HFS rich diets. Together, these findings reveal an association between HFS consumption and poorer hippocampal function in human participants, consistent with findings from animal-based studies. Moreover, our results suggest that this may be related to impaired regulation of energy intake via less accurate tracking of prior food intake and reduced sensitivity to hunger and satiety signals.
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Body Weight and Wages: Evidence from Add Health
Joseph Sabia & Daniel Rees
Economics & Human Biology, forthcoming
Abstract:
This note uses data from the National Longitudinal Study of Adolescent Health to examine the relationship between body weight and wages. Ordinary least squares (OLS) and individual fixed effects estimates provide evidence that overweight and obese white women are paid substantially less per hour than their slimmer counterparts. Two-stage least squares (2SLS) estimation confirms this relationship, suggesting that it is not driven by time-variant unobservables.
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Jason Block et al.
American Journal of Epidemiology, 15 November 2011, Pages 1108-1114
Abstract:
Existing evidence linking residential proximity to food establishments with body mass index (BMI; weight (kg)/height (m)2) has been inconclusive. In this study, the authors assessed the relation between BMI and proximity to food establishments over a 30-year period among 3,113 subjects in the Framingham Heart Study Offspring Cohort living in 4 Massachusetts towns during 1971-2001. The authors used novel data that included repeated measures of BMI and accounted for residential mobility and the appearance and disappearance of food establishments. They calculated proximity to food establishments as the driving distance between each subject's residence and nearby food establishments, divided into 6 categories. The authors used cross-classified linear mixed models to account for time-varying attributes of individuals and residential neighborhoods. Each 1-km increase in distance to the closest fast-food restaurant was associated with a 0.11-unit decrease in BMI (95% credible interval: -0.20, -0.04). In sex-stratified analyses, this association was present only for women. Other aspects of the food environment were either inconsistently associated or not at all associated with BMI. Contrary to much prior research, the authors did not find a consistent relation between access to fast-food restaurants and individual BMI, necessitating a reevaluation of policy discussions on the anticipated impact of the food environment on weight gain.
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Gary Goldfield et al.
PLoS ONE, November 2011, e26643
Objective: To examine the association between duration and type of screen time (TV, video games, computer time) and blood pressure (BP) and lipids in overweight and obese adolescents.
Design: This is a cross-sectional study of 282 overweight or obese adolescents aged 14-18 years (86 males, 196 females) assessed at baseline prior to beginning a lifestyle intervention study for weight control. Sedentary behaviours, defined as hours per day spent watching TV, playing video games, recreational computer use and total screen time were measured by self-report. We examined the associations between sedentary behaviours and BP and lipids using multiple linear regression.
Results: Seated video gaming was the only sedentary behaviour associated with elevated BP and lipids before and after adjustment for age, sex, pubertal stage, parental education, body mass index (BMI), caloric intake, percent intake in dietary fat, physical activity (PA) duration, and PA intensity. Specifically, video gaming remained positively associated with systolic BP (adjusted r = 0.13, β = 1.1, p<0.05) and total cholesterol/HDL ratio (adjusted r = 0.12, β = 0.14, p<0.05).
Conclusions: Playing video games was the only form of sedentary behaviour that was independently associated with increased BP and lipids. Our findings provide support for reducing time spent playing seated video games as a possible means to promote health and prevent the incidence of cardiovascular disease (CVD) risk factors in this high risk group of overweight and obese adolescents. Future research is needed to first replicate these findings and subsequently aim to elucidate the mechanisms linking seated video gaming and elevated BP and lipids in this high risk population.
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When Do Consumers Eat More? The Role of Appearance Self-Esteem and Food Packaging Cues
Jennifer Argo & Katherine White
Journal of Marketing, forthcoming
Abstract:
Prior research has found that under certain conditions, small packages can paradoxically increase consumption. The authors build on this work by suggesting that people low in appearance self-esteem (ASE) are particularly sensitive to external control properties (i.e., packaging-related factors that signal the ability of packaging to regulate food intake) and, as a result, increase consumption levels when packages are small (vs. large or absent). Factors that highlight the external control properties of small packages, such as the visibility of product quantity, location of the caloric content, and communicated caloric content, further increase consumption, particularly among people with low ASE. The underlying process appears to be, at least in part, cognitively driven. The effects are mitigated when participants are under cognitive load, and the findings are mediated by cognitions regarding the ability of small packages to regulate food intake. The results have important practical implications suggesting that to quell the effects of small packages on overconsumption, emphasis on the external control properties of small packages should be minimized.
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Dara Musher-Eizenman et al.
Journal of Early Childhood Research, October 2011, Pages 191-195
Abstract:
Caregivers often struggle with food neophobia on the part of young children. This study examined whether labeling novel healthy foods with fun names would increase children's willingness to try those foods and encourage them to eat more of those foods in a child care setting. Thirty-nine toddler and preschool age children (mean age = 3.9 years) were served each of three foods twice, once labeled with a fun name and once with a healthy name. Percentage of the food consumed by each child was recorded. Overall, children ate a greater percentage of the target foods when they were labeled with fun names. Also, a larger percentage of the children tasted the foods when they were labeled with fun names. This simple strategy could be effective for increasing consumption of healthy foods among young children.
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Janet Tomiyama, Mary Dallman & Elissa Epel
Psychoneuroendocrinology, November 2011, Pages 1513-1519
Abstract:
Chronically stressed rodents who are allowed to eat calorie-dense "comfort" food develop greater mesenteric fat, which in turn dampens hypothalamic-pituitary-adrenocortical (HPA) axis activity. We tested whether similar relations exist in humans, at least cross-sectionally. Fifty-nine healthy premenopausal women were exposed to a standard laboratory stressor to examine HPA response to acute stress and underwent diurnal saliva sampling for basal cortisol and response to dexamethasone administration. Based on perceived stress scores, women were divided into extreme quartiles of low versus high stress categories. We found as hypothesized that the high stress group had significantly greater BMI and sagittal diameter, and reported greater emotional eating. In response to acute lab stressor, the high stress group showed a blunted cortisol response, lower diurnal cortisol levels, and greater suppression in response to dexamethasone. These cross-sectional findings support the animal model, which suggests that long-term adaptation to chronic stress in the face of dense calories result in greater visceral fat accumulation (via ingestion of calorie-dense food), which in turn modulates HPA axis response, resulting in lower cortisol levels.
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Smoking and Body Weight: Evidence using Genetic Instruments
George Wehby et al.
Economics & Human Biology, forthcoming
Abstract:
Several studies have evaluated whether the high and rising obesity rates over the past three decades may be due to the declining smoking rates. There is mixed evidence across studies-some find negative smoking effects and positive cigarette cost effects on body weight, while others find opposite effects. This study applies a unique approach to identify the smoking effects on body weight and to evaluate the heterogeneity in these effects across the body mass index (BMI) distribution by utilizing genetic instruments for smoking. Using a data sample of 1,057 mothers from Norway, the study finds heterogeneous effects of cigarette smoking on BMI - smoking increases BMI at low/moderate BMI levels and decreases BMI at high BMI levels. The study highlights the potential advantages and challenges of employing genetic instrumental variables to identify behavior effects including the importance of qualifying the instruments and the need for large samples.
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Gender Comparisons of Fat Talk in the United Kingdom and the United States
Lucinda Payne et al.
Sex Roles, October 2011, Pages 557-565
Abstract:
This study compared different forms of body talk, including "fat talk," among 231 university men and women in central England (UK; n = 93) and the southeastern United States (US; n = 138). A 2 (gender) by 2 (country) repeated measures ANOVA across types of body talk (negative, self-accepting, positive) and additional Chi-square analyses revealed that there were differences across gender and between the UK and US cultures. Specifically, UK and US women were more likely to report frequently hearing or perceiving pressure to engage in fat talk than men. US women and men were also more likely to report pressure to join in self-accepting body talk than UK women and men.
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The Body Mass Index of Blacks and Whites in the United States during the Nineteenth Century
Scott Alan Carson
Journal of Interdisciplinary History, Winter 2012, Pages 371-391
Abstract:
Body mass index (BMI) values reflect the net balance between nutrition, work effort, and calories consumed to fight disease. Nineteenth-century prison records in the United States demonstrate that the BMI values of blacks and whites were distributed symmetrically; neither underweight nor obese individuals were common among the working class. BMI values declined throughout the nineteenth century. By modern standards, however, nineteenth-century BMIs were in healthy weight ranges, though the biological living standards in rural areas exceeded those in urban areas. The increase in BMIs during the twentieth century did not have its origin in the nineteenth century.
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The Freshman 15: A Critical Time for Obesity Intervention or Media Myth?
Jay Zagorsky & Patricia Smith
Social Science Quarterly, December 2011, Pages 1389-1407
Objectives: We test whether the phrase "Freshman 15" accurately describes weight change among first-year college students. We also analyze freshmen's weight change during and after college.
Methods: This is the first investigation of the "Freshman 15" to use a nationally representative random sample, the National Longitudinal Survey of Youth (NLSY97). The data are analyzed using descriptive statistics, regression analysis, simulations, and longitudinal analysis.
Results: Freshmen gain between 2.5 to 3.5 pounds, on average, over the course of their first year of college. Compared to same-age noncollege attendees, the typical freshman gains only an additional half-pound. Instead of a spike in weight during the freshman year, college-educated individuals exhibit moderate but steady weight gain during and after college.
Conclusion: Anti-obesity efforts directed specifically at college freshmen will likely have little impact on obesity prevalence among young adults.