No free lunch
Longitudinal Associations Between Poverty and Obesity From Birth Through Adolescence
Hedwig Lee et al.
American Journal of Public Health, May 2014, Pages e70-e76
Objectives: We examined the relationship between timing of poverty and risk of first-incidence obesity from ages 3 to 15.5 years.
Methods: We used the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (1991–2007) to study 1150 children with repeated measures of income, weight, and height from birth to 15.5 years in 10 US cities. Our dependent variable was the first incidence of obesity (body mass index ≥ 95th percentile). We measured poverty (income-to-needs ratio < 2) prior to age 2 years and a lagged, time-varying measure of poverty between ages 2 and 12 years. We estimated discrete-time hazard models of the relative risk of first transition to obesity.
Results: Poverty prior to age 2 years was associated with risk of obesity by age 15.5 years in fully adjusted models. These associations did not vary by gender.
Conclusions: Our findings suggest that there are enduring associations between early life poverty and adolescent obesity. This stage in the life course may serve as a critical period for both poverty and obesity prevention.
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Weight Labeling and Obesity: A Longitudinal Study of Girls Aged 10 to 19 Years
Jeffrey Hunger & Janet Tomiyama
JAMA Pediatrics, forthcoming
"The National Heart, Lung, and Blood Institute Growth and Health Study followed up girls who self-identified as black (n = 1213) or white (n = 1166) from age 10 years until age 19 years...Adjusting for baseline BMI, household income, parental education, race, and age at menarche, being labeled 'too fat' at age 10 years remained a significant predictor of obesity at age 19 years (odds ratio = 1.66). The odds ratio was 1.62 when family members were the source of labeling and 1.40 when nonfamily members were the source. These effects were not modulated by race."
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The Changing Face of Obesity: Exposure to and Acceptance of Obesity
Eric Robinson & Paul Christiansen
Obesity, May 2014, Pages 1380–1386
Objective: Adiposity has started to become the norm in many western countries. The current studies tested the hypothesis that exposure to heavier body weights will increase the acceptance of obesity, which could further propagate rises in body weight.
Methods: Across three experiments we examined the effect that exposing participants to photographs of either obese or healthy weight males had on later judgments about an obese male. We also tested how obesity exposure impacted upon visual preferences and how accepting participants were of obesity, to examine the mechanisms by which exposure to obesity increases acceptance of heavier body weights.
Results: In Experiment 1, obesity exposure resulted in an obese male being judged more positively, than after exposure to healthy weights. Experiment 2 replicated the effect that obesity exposure had on acceptability and demonstrated this effect was mediated by obesity exposure increasing how much participants liked the way an obese person looked. In Experiment 3, exposure to obesity resulted in participants being more likely to believe that an obese person did not need to lose weight.
Conclusions: Findings across these three studies were consistent and suggest that exposure to adiposity results in an increased acceptance of obesity, by altering visual preferences towards heavier body weights.
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Macronutrients and Obesity: Revisiting the Calories in, Calories out Framework
Daniel Riera-Crichton & Nathan Tefft
Economics & Human Biology, forthcoming
Abstract:
Recent clinical research has studied weight responses to varying diet composition, but the contribution of changes in macronutrient intake and physical activity to rising population weight remains controversial. Research on the economics of obesity typically assumes a “calories in, calories out” framework, but a weight production model separating caloric intake into carbohydrates, fat, and protein, has not been explored in an economic framework. To estimate the contributions of changes in macronutrient intake and physical activity to changes in population weight, we conducted dynamic time series and structural VAR analyses of U.S. data between 1974 and 2006 and a panel analysis of 164 countries between 2001 and 2010. Findings from all analyses suggest that increases in carbohydrates are most strongly and positively associated with increases in obesity prevalence even when controlling for changes in total caloric intake and occupation-related physical activity. Our structural VAR results suggest that, on the margin, a 1% increase in carbohydrates intake yields a 1.01 point increase in obesity prevalence over 5 years while an equal percent increase in fat intake decreases obesity prevalence by 0.24 points.
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The Role of Poverty Status and Obesity on School Attendance in the United States
Sandra Echeverría et al.
Journal of Adolescent Health, forthcoming
Purpose: Several studies have shown that obesity influences school performance. Little is known about the joint effect of poverty and obesity associated with school attendance.
Methods: Data are from the National Survey of Children's Health (N = 93,151), a nationally representative sample of U.S. youth aged 10–17 years. Our dependent variable was ≥11 days of school days missed per year. Body mass index was classified as normal, overweight, and obese using age- and sex-specific criteria. Federal poverty level (FPL) was classified as <200%, 200%–399%, and ≥400% (high income). Covariates included gender, age, child's race or ethnicity, maternal physical and mental health, child's health, family composition, and household tobacco use. Logistic regression models and prevalence ratios were estimated, accounting for the complex survey design.
Results: The odds of missing ≥11 days of school among overweight youth was 1.5 times that of normal-weight youth (95% confidence interval (CI) = 1.22–1.85) and 1.7 (95% CI = 1.35–2.13) times among obese youth in fully adjusted models. In joint effects models, the probability of missing school was significantly greater for obese youth in both the <200% FPL group (prevalence ratio = 1.78, CI = 1.36–2.34) and the ≥400% FPL group (prevalence ratio = 2.88, CI = 1.91–4.35), when compared with their normal-weight, higher income peers. Predicted probabilities revealed sharper gradients for higher income youth.
Conclusions: Obesity influences school absenteeism across all income categories. Nonetheless, there may be distinct reasons for missing school for lower and higher income youth, and the long-term consequences of school absences may also differ for these populations.
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Nicole Larson et al.
American Journal of Public Health, May 2014, Pages e62-e69
Objectives: We examined trends from 1999 to 2010 in adolescents’ self-reported fast-food restaurant use alongside maternal reports of fast-food consumption and purchasing from restaurants for family meals.
Methods: Middle- and high-school student participants from Minneapolis–St Paul, Minnesota, represented diverse ethnic/racial and socioeconomic backgrounds. Adolescents completed classroom-administered surveys and maternal caregivers responded by phone or mail.
Results: The overall prevalence of frequent fast-food consumption, defined as 3 or more times per week, decreased from 1999 to 2010 among adolescents (1999: 25%; 2010: 19%; P < .001) and maternal caregivers (1999: 17%; 2010: 11%; P < .001), but sociodemographic disparities were apparent. For example, the prevalence of frequent fast-food consumption remained highest and did not significantly decrease among Black or Native American youths. The overall prevalence of frequent fast-food purchases for family meals did not significantly decrease; large decreases were observed only among Hispanic families (1999: 18%; 2010: 6%; P < .001).
Conclusions: In light of previous findings linking frequent fast-food consumption to greater weight gain and poor nutrition, the observed decreases in consumption are encouraging and interventions are needed to address observed disparities.
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Young Suh et al.
Obesity, forthcoming
Objective: Public attitudes about three proposed laws prohibiting weight discrimination in the US, from 2011 to 2013 were examined.
Methods: An online survey using a diverse national sample of US adults to assess their level of support for three specific laws against weight discrimination was conducted. Data collection occurred between June and July in 2011 (n = 1,098), 2012 (n = 1,202), and 2013 (n = 1,202).
Results: Between 2011 and 2013, support for laws prohibiting weight discrimination remained consistent, and in some cases became increasingly supportive, primarily in 2012-2013. At least 75% of participants consistently favored laws prohibiting weight discrimination in the workplace. Individuals became increasingly supportive of extending disability protections for individuals with obesity (62% in 2011 to 69% in 2013) and adding body weight as a protected class in Civil Rights statutes (70% in 2011 to 76% in 2013). Analyses highlight specific predictors of support (gender, race, education, and political affiliation).
Conclusions: There is strong, consistent support for policies prohibiting weight discrimination. These findings have important implications for developing specific antidiscrimination legislation to protect Americans with obesity and improve their quality of life.
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Kirstin Aschbacher et al.
Psychoneuroendocrinology, August 2014, Pages 14–22
Background: In preclinical studies, the combination of chronic stress and a high sugar/fat diet is a more potent driver of visceral adiposity than diet alone, a process mediated by peripheral Neuropeptide Y (NPY).
Methods: In a human model of chronic stress, we investigated whether the synergistic combination of highly palatable foods (HPF; high sugar/fat) and stress was associated with elevated metabolic risk. Using a case-control design, we compared 33 post-menopausal caregivers (the chronic stress group) to 28 age-matched low-stress control women on reported HPF consumption (modified Block Food Frequency Questionnaire), waistline circumference, truncal fat ultrasound, and insulin sensitivity using a three-hour oral glucose tolerance test. A fasting blood draw was assayed for plasma NPY and oxidative stress markers (8-hydroxyguanosine and F2-Isoprostanes).
Results: Among chronically stressed women only, greater HPF consumption was associated with greater abdominal adiposity, oxidative stress, and insulin resistance at baseline (all p's ≤.01). Furthermore, plasma NPY was significantly elevated in chronically stressed women (p<.01), and the association of HPF with abdominal adiposity was stronger among women with high versus low NPY. There were no significant predictions of change over one-year, likely due to high stability (little change) in the primary outcomes over this period.
Discussion: Chronic stress is associated with enhanced vulnerability to diet-related metabolic risk (abdominal adiposity, insulin resistance, and oxidative stress). Stress-induced peripheral NPY may play a mechanistic role.
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Scott Alan Carson & Paul Hodges
Mathematical Population Studies, Spring 2014, Pages 78-94
Abstract:
Nineteenth-century U.S. Black and White body mass indexes (BMIs) were distributed symmetrically; neither wasting nor obesity was common. BMI values were also greater for Blacks than for Whites. During industrialization in the nineteenth century in the United States, there was a negative relationship between BMIs and average state-level wealth and an inverse relationship between BMI and wealth inequality. After controlling for wealth and inequality, rural agricultural farmers had greater BMI values than their urban counterparts in other occupations.
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An 8-month exercise intervention alters frontotemporal white matter integrity in overweight children
David Schaeffer et al.
Psychophysiology, forthcoming
Abstract:
In childhood, excess adiposity and low fitness are linked to poor academic performance, lower cognitive function, and differences in brain structure. Identifying ways to mitigate obesity-related alterations is of current clinical importance. This study examined the effects of an 8-month exercise intervention on the uncinate fasciculus, a white matter fiber tract connecting frontal and temporal lobes. Participants consisted of 18 unfit, overweight 8- to 11-year-old children (94% Black) who were randomly assigned to either an aerobic exercise (n = 10) or a sedentary control group (n = 8). Before and after the intervention, all subjects participated in a diffusion tensor MRI scan. Tractography was conducted to isolate the uncinate fasciculus. The exercise group showed improved white matter integrity as compared to the control group. These findings are consistent with an emerging literature suggesting beneficial effects of exercise on white matter integrity.
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Eyes in the Aisles: Why Is Cap’N Crunch Looking Down at My Child?
Aner Tal, Aviva Musicus & Brian Wansink
Environment and Behavior, April 2014
Abstract:
To what extent do cereal spokes-characters make eye contact with children versus adults, and does their eye contact influence choice? The shelf placement and eye positioning of 86 cereal spokes-characters were evaluated in ten grocery stores in the Eastern United States. In Study 1, we calculated the average height of cereal boxes on the shelf for adult- versus children-oriented cereals (48 versus 23-in.) and the inflection angle of spokes-characters’ gaze (0.4 versus -9.6 degrees). We found that cereal characters on children- (adult-) oriented cereals make incidental eye contact at children’s (adults’) eye level. In Study 2, we showed that eye contact with cereal spokes-characters increased feelings of trust and connection to the brand, as well as choice of the brand over competitors. Currently, many of the cereals targeted towards children are of the heavily sugared, less healthy variety. One potential application of this finding would be to use eye contact with spokes-characters to promote healthy choices and healthier food consumption.
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Angela Green et al.
Obesity, May 2014, Pages E157–E163
Objective: The purpose of this study was to examine the relationship between usual sugar-sweetened beverage (SSB) consumption and prevalence of abnormal metabolic health across body mass index (BMI) categories.
Methods: The metabolic health of 6,842 non-diabetic adults was classified using cross-sectional data from the Framingham Heart Study Offspring (1998-2001) and Third Generation (2002-2005) cohorts. Adults were classified as normal weight, overweight or obese and, within these categories, metabolic health was defined based on five criteria—hypertension, elevated fasting glucose, elevated triglycerides, low HDL cholesterol, and insulin resistance. Individuals without metabolic abnormalities were considered metabolically healthy. Logistic regression was used to examine the associations between categories of SSB consumption and risk of metabolic health after stratification by BMI.
Results: Comparing the highest category of SSB consumers (median of 7 SSB per week) to the lowest category (non-consumers), odds ratios (95% confidence intervals) for metabolically abnormal phenotypes, compared to the metabolically normal, were 1.9 (1.1-3.4) among the obese, 2.0 (1.4-2.9) among the overweight, and 1.9 (1.4-2.6) among the normal weight individuals.
Conclusions: In this cross-sectional analysis, it is observed that, irrespective of weight status, consumers of SSB were more likely to display metabolic abnormalities compared to non-consumers in a dose-dependent manner.
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Katie Martin et al.
PLoS ONE, April 2014
Introduction: Research on urban food environments emphasizes limited access to healthy food, with fewer large supermarkets and higher food prices. Many residents of Hartford, Connecticut, which is often considered a food desert, buy most of their food from small and medium-sized grocery stores. We examined the food environment in greater Hartford, comparing stores in Hartford to those in the surrounding suburbs, and by store size (small, medium, and large).
Methods: We surveyed all small (over 1,000 ft2), medium, and large-sized supermarkets within a 2-mile radius of Hartford (36 total stores). We measured the distance to stores, availability, price and quality of a market basket of 25 items, and rated each store on internal and external appearance. Geographic Information System (GIS) was used for mapping distance to the stores and variation of food availability, quality, and appearance.
Results: Contrary to common literature, no significant differences were found in food availability and price between Hartford and suburban stores. However, produce quality, internal, and external store appearance were significantly lower in Hartford compared to suburban stores (all p<0.05). Medium-sized stores had significantly lower prices than small or large supermarkets (p<0.05). Large stores had better scores for internal (p<0.05), external, and produce quality (p<0.01). Most Hartford residents live within 0.5 to 1 mile distance to a grocery store.
Discussion: Classifying urban areas with few large supermarkets as ‘food deserts’ may overlook the availability of healthy foods and low prices that exist within small and medium-sized groceries common in inner cities. Improving produce quality and store appearance can potentially impact the food purchasing decisions of low-income residents in Hartford.
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Life Cycle Development of Obesity and Its Determinants in Six European Countries
Sandra Cavaco, Tor Eriksson & Ali Skalli
Economics & Human Biology, forthcoming
Abstract:
This paper empirically examines the effect of parents’ and individuals’ own socioeconomic status on overweight and obesity, and investigates how this effect changes over the life cycle. The impact of individuals’ health behaviours on their obesity status later in life is also studied. We use data from Denmark, Finland, France, Greece, the Netherlands and the U.K. in which 4,595 individuals aged 50 to 65 are surveyed and where individuals’ height and weight at different ages (25, 35, 45 and current age) are available. We perform “repeated cross-sections” analyses as well as dynamic probit analyses of the individuals’ obesity histories. We contribute to the literature by examining the role of a variety of obesity determinants over the whole life cycle, not only over a certain portion of individuals’ lives. Key findings are: (i) parents’ socioeconomic status predicts obesity in early adulthood whereas the individual's own socioeconomic status as adult is more important in explaining obesity at later stages of the life cycle, (ii) changes in obesity status are associated with changes in health behaviours, (iii) obesity in late adulthood is strongly and positively correlated with overweight and obesity in younger ages, and (iv) cross-country differences in obesity and overweight largely remain after controlling for parental and childhood factors and individuals’ health behaviours.
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M.H. Reichkendler et al.
Obesity, May 2014, Pages 1220–1232
Objective: The dose–response effects of exercise training on insulin sensitivity, metabolic risk, and quality of life were examined.
Methods: Sixty-one healthy, sedentary (VO2max: 35 ± 5 ml/kg/min), moderately overweight (BMI: 27.9 ± 1.8), young (age: 29 ± 6 years) men were randomized to sedentary living (sedentary control group; n = 18), moderate (moderate dose training group [MOD]: 300 kcal/day, n = 21), or high (high dose training group [HIGH]: 600 kcal/day, n = 22) dose physical exercise for 11 weeks.
Results: The return rate for post-intervention testing was 82-94% across groups. Weekly exercise amounted to 2,004 ± 24 and 3,774 ± 68 kcal, respectively, in MOD and HIGH. Cardiorespiratory fitness increased (P < 0.001) 18 ± 3% in MOD and 17 ± 3% in HIGH, and fat percentage decreased (P < 0.001) similarly in both exercise groups (MOD: 32 ± 1 to 29 ± 1%; HIGH: 30 ± 1 to 27 ± 1%). Peripheral insulin sensitivity increased (P < 0.01) (MOD: 28 ± 7%; HIGH: 36 ± 8%) and the homeostasis model assessment of insulin resistance decreased (P < 0.05) (MOD: -17 ± 7%; HIGH: -18 ± 10%). The number of subjects meeting the criteria of the metabolic syndrome decreased by 78% in MOD (P < 0.01) and by 80% in HIGH (P < 0.05). General health assessed by questionnaire increased similarly in MOD (P < 0.05) and HIGH (P < 0.01).
Conclusions: Only minor additional health benefits were found when exercising ∼3,800 as opposed to ∼2,000 kcal/week in young moderately overweight men. This finding may have important public health implications.
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Adolescent obesity, educational attainment and adult earnings
John Amis, Andrew Hussey & Albert Okunade
Applied Economics Letters, forthcoming
Abstract:
We estimate the effects of being obese during adolescence on the likelihood of high school graduation, post-secondary educational attainment and labour market earnings as an adult (over 13 years later). We use longitudinal data from the National Longitudinal Survey of Adolescent Health (Add Health), conducted by the Carolina Population Center of the University of North Carolina at Chapel Hill. This is a nationally representative sample of students in grades 7 through 12 for the 1994–1995 first wave survey. Three subsequent waves of follow-up interviews occurred in 1996, 2001–2002 and finally in 2007–2008, when the sample was aged 25–31. Probit and linear regression models with a large set of controls (to minimize any bias that may result from omitting factors related to both adolescent obesity and adult outcomes) are fitted to carry out analyses separately by gender or racial groups. Pathological body weights are most notably present among males, blacks and Hispanics, suggesting possibility that diverging obesity effects may be found across race and gender groups. Unlike some prior research, we find no significant effects of adolescent obesity on high school graduation, but for some demographic groups, negative effects are found on college graduation and future income. Policy implications are discussed.
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Benjamin House et al.
Obesity, May 2014, Pages E77–E84
Objective: To investigate the impact of eating frequency on dietary intake, physical activity (PA), metabolic, and adiposity measures in minority youth.
Methods: This analysis included 185 overweight (≥85th BMI percentile) Hispanic and African-American youth (8-18 years) with the following cross-sectional measures: height, weight, BMI, dietary intake, body composition, metabolic parameters, PA, visceral adipose tissue (VAT), and subcutaneous adipose tissue. Each eating occasion (EO) was defined as ≥50 calories and ≥15 minutes from any previous EO. Participants were dichotomized based on EOs per 24-h into meal skippers <3 EO (MS; n = 27) or normal/frequent eaters ≥3 EO (NFE; n = 158). ANCOVAs were used to assess dietary intakes, metabolic outcomes, adiposity, and PA between eating frequency groups.
Results: MS compared to NFE consumed 24% fewer calories per 24-h (P ≤ 0.01), 21% more calories per EO (P ≤ 0.01), ate 40% less often (P ≤ 0.01), had 18% higher triglycerides (P = 0.03), and 26% more VAT (P = 0.03), with no differences in PA.
Conclusions: Although meal skipping was associated with decreased energy intake, it was linked to increased calories per EO and higher triglycerides and VAT, which are strong indicators of deleterious metabolic profiles. These findings elucidate that meal skipping may be associated with increased VAT and related metabolic diseases in high-risk minority youth.
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Evidence that a Very Brief Psychological Intervention Boosts Weight Loss in a Weight Loss Program
Christopher Armitage et al.
Behavior Therapy, forthcoming
Abstract:
Reducing morbidity and mortality associated with being overweight is a crucial public health goal. The aim of the present research was to test the efficacy of a very brief psychological intervention (a volitional help sheet) that could be used as an adjunct to standard weight loss programs to support increased weight loss in an overweight sample. Seventy-two overweight participants currently participating in a weight loss program were randomly allocated to either an intervention (volitional help sheet) condition or a control (distracter task) condition. The main outcome measure was weight at one-month follow-up. Participants in both conditions lost significant amounts of weight, but those in the intervention condition lost significantly more than those in the control condition (d = 0.66). The findings support the efficacy of the volitional help sheet to promote additional weight loss in an overweight sample engaged in a weight loss program. The volitional help sheet therefore represents a very brief, low-cost, intervention that could be used to supplement ongoing weight-loss programs.
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Using the Oaxaca–Blinder decomposition as an empirical tool to analyze racial disparities in obesity
Bisakha Sen
Obesity, forthcoming
Objective: Racial disparities in obesity in the US are often assumed to reflect racial disparities in socio-economic status, diet and physical-activity. We present an econometric method that helps examine this by “decomposing” the racial gap in body-mass index (BMI) into how much can be explained by racial differences in “standard” predictors of BMI, and how much remains unexplained.
Methods: The Oaxaca–Blinder decomposition is widely used in other fields, but remains under-utilized in the obesity literature. We provide algebraic and graphical illustrations of the decomposition, and further illustrate it with an example using data for white and black respondents in Mississippi and Alabama. BMI is the outcome of interest. Predictor variables include income, education, age, marital status, children, mental health indicators, diet and exercise.
Results: The mean predicted gap in BMI between white and black men is small, statistically insignificant, and can be attributed to racial differences in the predictor variables. The mean predicted gap for women is larger, statistically significant, and <10% of it can be explained by differences in predictor variables. Implications of the findings are discussed.
Conclusion: Wider application of this method is advocated in the obesity literature, to better understand racial disparities in obesity.
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Gamification of Dietary Decision-Making in an Elementary-School Cafeteria
Brooke Jones et al.
PLoS ONE, April 2014
Abstract:
Despite the known health benefits of doing so, most US children do not consume enough fruits and vegetables (FV). School-based interventions can be effective in increasing FV consumption, but the most effective of these require that schools allocate their time, effort, and financial resources to implementing the program: expenditures that schools may be reluctant to provide in climates of academic accountability and economic austerity. The present demonstration project used a behaviorally based gamification approach to develop an intervention designed to increase FV consumption while minimizing material and labor costs to the school. During the intervention, the school (N = 180 students in grades K-8) played a cooperative game in which school-level goals were met by consuming higher-than-normal amounts of either fruit or vegetables (alternating-treatments experimental design). School-level consumption was quantified using a weight-based waste measure in the cafeteria. Over a period of 13 school days, fruit consumption increased by 66% and vegetable consumption by 44% above baseline levels. Use of an alternating-treatment time-series design with differential levels of FV consumption on days when fruit or vegetable was targeted for improvement supported the role of the intervention in these overall consumption increases. In post-intervention surveys, teachers rated the intervention as practical in the classroom and enjoyed by their students. Parent surveys revealed that children were more willing to try new FV at home and increased their consumption of FV following the intervention. These findings suggest that a behaviorally based gamification approach may prove practically useful in addressing concerns about poor dietary decision-making by children in schools.