Mouthing off
Fifty years of fat: News coverage of trends that predate obesity prevalence
Brennan Davis & Brian Wansink
BMC Public Health, July 2015
Background: Obesity prevalence has risen in fifty years. While people generally expect media mentions of health risks like obesity prevalence to follow health risk trends, food consumption trends may precede obesity prevalence trends. Therefore, this research investigates whether media mentions of food predate obesity prevalence.
Methods: Fifty years of non-advertising articles in the New York Times (and 17 years for the London Times) are coded for the mention of less healthy (5 salty and 5 sweet snacks) and healthy (5 fruits and 5 vegetables) food items by year and then associated with annual obesity prevalence in subsequent years. Time-series generalized linear models test whether food-related mentions predate or postdate obesity prevalence in each country.
Results: United States obesity prevalence is positively associated with New York Times mentions of sweet snacks (b = 55.2, CI = 42.4 to 68.1, p = .000) and negatively associated with mentions of fruits (b = −71.28, CI −91.5 to −51.1, p = .000) and vegetables (b = −13.6, CI = −17.5 to −9.6, p = .000). Similar results are found for the United Kingdom and The London Times. Importantly, the “obesity followed mentions” models are stronger than the “obesity preceded mentions” models.
Conclusions: It may be possible to estimate a nation’s future obesity prevalence (e.g., three years from now) based on how frequently national media mention sweet snacks (positively related) and vegetables or fruits (negatively related) today. This may provide public health officials and epidemiologists with new tools to more quickly assess the effectiveness of current obesity interventions based on what is mentioned in the media today.
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Hexuan Liu & Guang Guo
American Sociological Review, August 2015, Pages 705-737
Abstract:
This study demonstrates that body mass in middle and late adulthood is a consequence of the complex interplay among individuals’ genes, lifetime socioeconomic experiences, and the historical context in which they live. Drawing on approximately 9,000 genetic samples from the Health and Retirement Study, we first investigate how socioeconomic status (SES) over the life course moderates the impact of 32 established obesity-related genetic variants on body mass index (BMI) in middle and late adulthood. We then consider differences across birth cohorts in the genetic influence on BMI, and cohort variations in the moderating effects of life-course SES on the genetic influence. Our analyses suggest that persistently low SES over the life course or downward mobility (e.g., high SES in childhood but low SES in adulthood) amplify the genetic influence on BMI, and persistently high SES or upward mobility (e.g., low SES in childhood but high SES in adulthood) compensate for such influence. For more recent birth cohorts, the genetic influence on BMI becomes stronger, but the moderating effects of lifetime SES on the genetic influence are weaker compared to earlier cohorts. We discuss these findings in light of social changes during the obesity epidemic in the United States.
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Childhood Obesity and Cognitive Achievement
Nicole Black, David Johnston & Anna Peeters
Health Economics, September 2015, Pages 1082–1100
Abstract:
Obese children tend to perform worse academically than normal-weight children. If poor cognitive achievement is truly a consequence of childhood obesity, this relationship has significant policy implications. Therefore, an important question is to what extent can this correlation be explained by other factors that jointly determine obesity and cognitive achievement in childhood? To answer this question, we exploit a rich longitudinal dataset of Australian children, which is linked to national assessments in math and literacy. Using a range of estimators, we find that obesity and body mass index are negatively related to cognitive achievement for boys but not girls. This effect cannot be explained by sociodemographic factors, past cognitive achievement or unobserved time-invariant characteristics and is robust to different measures of adiposity. Given the enormous importance of early human capital development for future well-being and prosperity, this negative effect for boys is concerning and warrants further investigation.
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Body weight, mental health capital, and academic achievement
Joseph Sabia & Daniel Rees
Review of Economics of the Household, September 2015, Pages 653-684
Abstract:
Although obese students are more likely to exhibit the symptoms of depression than their slimmer counterparts and often do poorly in school, it is not clear whether these associations are spurious or causal in nature. Drawing on data from the National Longitudinal Study of Adolescent Health, we use an instrumental variables (IV) approach to distinguish between these hypotheses. IV estimates suggest that body weight leads to decreased self-esteem and increased depressive symptomatology among female, but not male, respondents. In addition, we find that body weight is negatively related to female academic achievement. Finally, we explore the degree to which the relationship between body weight and female academic achievement is explained by psychological wellbeing. We find that psychological wellbeing accounts for up to 30 % of this relationship.
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Martin Reimann, Antoine Bechara & Deborah MacInnis
Journal of Experimental Psychology: Applied, forthcoming
Abstract:
Despite much effort to decrease food intake by altering portion sizes, “super-sized” meals are the preferred choice of many. This research investigated the extent to which individuals can be subtly incentivized to choose smaller portion sizes. Three randomized experiments (two in the lab and one in the field) established that individuals’ choice of full-sized food portions is reduced when they are given the opportunity to choose a half-sized version with a modest non-food incentive. This substitution effect was robust across different non-food incentives, foods, populations, and time. Experiment 1 established the effect with children, using inexpensive headphones as non-food incentives. Experiment 2 — a longitudinal study across multiple days — generalized this effect with adults, using the mere chance to win either gift cards or frequent flyer miles as non-food incentives. Experiment 3 demonstrated the effect among actual restaurant customers who had originally planned to eat a full-sized portion, using the mere chance to win small amounts of money. Our investigation broadens the psychology of food portion choice from perceptual and social factors to motivational determinants.
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Visual Illusions and Inattention: Their Association with Adiposity Among Adolescent Girls
Lance Bauer
Appetite, December 2015, Pages 310–316
Abstract:
The Delboeuf concentric circle illusion is frequently invoked as an explanation for the hypothesized association between dinner plate size and overeating. We examined its association with adiposity among 162 girls, aged 14-18 years. We also examined the association of adiposity with neural and behavioral responses during a separate visual discrimination task. The analysis showed that girls with a body mass index percentile >=85, or with greater triceps skinfold thickness, exhibited less sensitivity to the Delboeuf illusion than girls with normal adiposity. The excess adiposity group also exhibited significantly smaller electroencephalographic responses and more errors during the separate visual discrimination task. In combination, the findings from the two tasks suggest that girls with an elevated body mass are less sensitive to visual cues in their environment. The implications of these findings for weight loss education should be considered.
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Obesity, Weight Loss, and Employment Prospects: Evidence from a Randomized Trial
Arndt Reichert
Journal of Human Resources, Summer 2015, Pages 759-810
Abstract:
This study presents credible estimates for the causal effect of BMI growth on employment among the obese. By exploring random assignment of a weight-loss intervention based on monetary rewards, I provide convincing evidence that weight loss positively affects the employment prospects of obese women but not of obese men. Consistent with this, significant effects of weight loss on proxy variables for labor productivity are found only for obese women.
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Parental Work Schedules and Child Overweight or Obesity: Does Family Structure Matter?
Daniel Miller & Jina Chang
Journal of Marriage and Family, forthcoming
Abstract:
The authors used longitudinal data from the Fragile Families and Child Wellbeing Study (N = 5,482) to investigate whether maternal and paternal work schedules affect child overweight or obesity. They took the novel step of examining whether this effect is consistent for children living in different family structures. Findings from child fixed effects models suggest that the probability of child overweight or obesity was higher for children living with mothers who worked standard shifts at a primary job and nonstandard shifts at a secondary job compared to children living with mothers who worked a standard shift at a primary job only. Fathers' work schedules were not associated with child overweight or obesity. Unexpectedly, maternal standard shift work at a primary job and nonstandard shift work at a secondary job was associated with overweight or obesity only among children living with married biological parents.
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Lewis James, Mark Funnell & Samantha Milner
Appetite, December 2015, Pages 132–137
Abstract:
Observational studies suggest that increased fruit and vegetable consumption can contribute to weight maintenance and facilitate weight loss when substituted for other energy dense foods. Therefore, the purpose of the present study was to assess the effect of berries on acute appetite and energy intake. Twelve unrestrained pre-menopausal women (age 21 ± 2 y; BMI 26.6 ± 2.6 kg∙m-2; body fat 23 ± 3 %) completed a familiarisation trial and two randomised experimental trials. Subjects arrived in the evening (∼5pm) and consumed an isoenergetic snack (65 kcal) of mixed berries (BERRY) or confectionary sweets (CONF). Sixty min later, subjects consumed a homogenous pasta test meal until voluntary satiation, and energy intake was quantified. Subjective appetite (hunger, fullness, desire to eat and prospective food consumption) was assessed throughout trials, and for 120 min after the test meal. Energy intake was less (P<0.001) after consumption of the BERRY snack (691 ± 146 kcal) than after the CONF snack (824 ± 172 kcal); whilst water consumption was similar (P=0.925). There were no trial (P>0.095) or interaction (P>0.351) effects for any subjective appetite ratings. Time taken to eat the BERRY snack (4.05 ± 1.12 min) was greater (P<0.001) than the CONF snack (0.93 ± 0.33 min). This study demonstrates that substituting an afternoon confectionary snack with mixed berries decreased subsequent energy intake at dinner, but did not affect subjective appetite. This dietary strategy could represent a simple method for reducing daily energy intake and aiding weight management.
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A Tailored Family-Based Obesity Intervention: A Randomized Trial
Rachael Taylor et al.
Pediatrics, August 2015, Pages 281-289
Objective: To determine whether a 2-year family-based intervention using frequent contact and limited expert involvement was effective in reducing excessive weight compared with usual care.
Methods: Two hundred and six overweight and obese (BMI ≥85th percentile) children aged 4 to 8 years were randomized to usual care (UC) or tailored package (TP) sessions at university research rooms. UC families received personalized feedback and generalized advice regarding healthy lifestyles at baseline and 6 months. TP families attended a single multidisciplinary session to develop specific goals suitable for each family, then met with a mentor each month for 12 months, and every third month for another 12 months to discuss progress and provide support. Outcome measurements (anthropometry, questionnaires, dietary intake, accelerometry) were obtained at 0, 12, and 24 months.
Results: BMI at 24 months was significantly lower in TP compared with UC children (difference, 95% confidence interval: –0.34, –0.65 to –0.02), as was BMI z score (–0.12, –0.20 to –0.04) and waist circumference (–1.5, –2.5 to –0.5 cm). TP children consumed more fruit and vegetables (P = .038) and fewer noncore foods (P = .020) than UC children, and fewer noncore foods were available in the home (P = .002). TP children were also more physically active (P = .035). No differences in parental feeding practices, parenting, quality of life, child sleep, or behavior were observed.
Conclusions: Frequent, low-dose support was effective for reducing excessive weight in predominantly mild to moderately overweight children over a 2-year period. Such initiatives could feasibly be incorporated into primary care.
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Calorie Label Formats: Using Numbers or Traffic Lights to Reduce Lunch Calories
Eric VanEpps, Julie Downs & George Loewenstein
Journal of Public Policy & Marketing, forthcoming
Abstract:
In a field experiment involving online workplace lunch orders, this study examines the impact of numeric and traffic light calorie labels on calorie intake. Employees of a large corporation ordered lunches through a website of the authors' design, on which they were presented menus with numeric calorie labels, traffic light labels, or both together, and the calorie content of their lunches was compared to that of diners randomized to receive no calorie information. Each label type reduced lunch calories by about 10 percent. Nutrition knowledge was not improved by any menu format. Traffic light labels achieved meaningful reductions in calories ordered even in the absence of numeric information, and there was no apparent benefit or detriment of combining label types. These findings suggest that consumers may benefit most from help in identifying relatively healthier choices, but rely little on information about the exact caloric content of items.