Tuesday, February 5, 2013
Feast and famine
Juliano Laran & Anthony Salerno
Psychological Science, forthcoming
Do people's perceptions that they live in a harsh environment influence their food choices? Drawing on life-history theory, we propose that cues indicating that the current environment is harsh (e.g., news about an economic crisis, the sight of people facing adversity in life) lead people to perceive that resources in the world are scarce. As a consequence, people seek and consume more filling and high-calorie foods, which they believe will sustain them for longer periods of time. Although perceptions of harshness can promote unhealthy eating, we show how this effect can be attenuated and redirected to promote healthier food choices.
Jordi Quoidbach & Elizabeth Dunn
Social Psychological and Personality Science, forthcoming
The present research provides the first evidence that temporarily giving up something pleasurable may provide an effective route to happiness. Participants were asked to eat a piece of chocolate during two lab sessions, held 1week apart. During the intervening week, we randomly assigned them to abstain from chocolate or to eat as much of it as possible, while a control group received no special instructions related to their chocolate consumption. At the second lab session, participants who had temporarily given up chocolate savored it significantly more and experienced more positive moods after eating it, compared to those in either of the other two conditions. Many cultural and religious practices entail temporarily giving up something pleasurable, and our research suggests that such self-denial may carry ironic benefits for well-being by combating hedonic adaptation.
Ellen van Kleef, Mitsuru Shimizu & Brian Wansink
Food Quality and Preference, January 2013, Pages 96-100
Could smaller snack portions be similarly effective in decreasing cravings or feelings of hunger as larger portions? To answer this, three common snack foods - chocolate, apple pie, potato chips - were given to 104 participants as either a small portion (x) or a substantially larger portion (5-10x). Results indicate that smaller portions satisfied one's ratings of hunger and craving similar to larger portions, but led to a mean intake that was significantly lower than in the large portion condition (with a difference of 103 calories). This suggests that 15 min after eating a considerably smaller snack, people will have eaten much less but will feel equally satisfied.
Sana Sheikh, Lucia Botindari & Emma White
Journal of Experimental Social Psychology, forthcoming
Moralization is the process whereby preferences are converted to values. Two studies used an embodied metaphor approach, in which moral metaphors are grounded in one's sense of physical cleanliness, to investigate whether restrained eating practices are moralized among women. Specifically, we predicted that the regulation of food intake by women is embodied in their feelings of physical cleanliness. Study 1 found that failures of restrained eating (i.e., overeating) increased accessibility of physical cleanliness-related words for women, but not men. Study 2 found that increased negative moral emotions fully mediated the effect of overeating on a desire for physical cleanliness. Overall, the studies argue for the importance of morality in restrained eating and in the central role of emotions in the embodiment of cognitive metaphors.
Jennifer Kraschnewski et al.
Medical Care, February 2013, Pages 186-192
Background: Guidelines recommend that physicians screen all adults for obesity and offer an intensive counseling and behavioral interventions for weight loss for obese adults. Current trends of weight-related counseling are unknown in the setting of the US obesity epidemic.
Objectives: To describe primary care physician (PCP) weight-related counseling, comparing counseling rates in 1995-1996 and 2007-2008.
Research Design: Data analysis of outpatient PCP visits in 1995-1996 and 2007-2008, as reported in the National Ambulatory Medical Care Survey.
Subjects: A total of 32,519 adult primary care visits with PCPs.
Measures: Rates of counseling for weight, diet, exercise, and a composite variable, weight-related counseling (defined as counseling for weight, diet, or exercise) between survey years. Adjusted analyses controlled for patient and visit characteristics.
Results: Weight counseling declined from 7.8% of visits in 1995-1996 to 6.2% of visits in 2007-2008 [adjusted odds ratios, 0.64; 95% confidence intervals, 0.53, 0.79]. Rates of receipt of diet, exercise, and weight-related counseling similarly declined. Greater declines in odds of weight-counseling receipt were observed among those with hypertension (47%), diabetes (59%), and obesity (41%), patients who stand the most to gain from losing weight.
Conclusions: Rates of weight counseling in primary care have significantly declined despite increased rates of overweight and obesity in the United States. Further, these declines are even more marked in patients with obesity and weight-related comorbidities, despite expectations to provide such care by both patients and policymakers. These findings have implications for determining deliverable, novel ways to engage PCPs in addressing the obesity epidemic.
Katherine Flegal et al.
Journal of the American Medical Association, 2 January 2013, Pages 71-82
Importance: Estimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting.
Objective: To perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population.
Data Sources: PubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions.
Study Selection: Articles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270 000 deaths.
Data Extraction: Data were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking).
Results: Random-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.
Conclusions and Relevance: Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
Richard Volpe, Abigail Okrent & Ephraim Leibtag
American Journal of Agricultural Economics, forthcoming
We examine the effect of supercenter market share on consumers' food-at-home purchasing habits in the United States. We measure healthfulness several different ways to ensure robustness, but all measurements place a greater value on fresh fruits and vegetables and whole grains than on processed foods high in sugar and sodium. We find that from 1998-2006 consumers generally purchased less healthful foods at supercenters than they do at supermarkets. Moreover, a one-percent increase in the local market share of supercenters results in a decrease in purchase healthfulness for groceries of 0.10 to 0.46 percent. This relationship is statistically significant and robust.
Janice Johnson Dias & Gregory Price
Review of Black Political Economy, December 2012, Pages 381-388
Black American women are shrinking in height at a faster rate than other groups, a phenomenon that has consequences for the physical health and economic well-being of black females. Relative to the cohort born from 1955 to 1974, the most recent cohort (1970-1986) of black American women and girls have lost more than half an inch (approximately 0.56) in height. Adult height is a measure of net nutrition acquired during childhood and adolescence and is correlated with a wide variety of economic and health outcomes. Simultaneously, the body mass index (BMI) among blacks has also increased at a faster rate than whites in both the periods of 1988-1994 (1.06 kg/m2) and 1999-2002. Black women and girls, in particular, experienced the greatest increase in BMI since the 1990s. Evidence that black American women are shrinking and BMI is growing highlights the need to examine the nutritional intake of black girls during childhood and adolescence; early nutritional deficiencies have persistent impact over their life course. In this policy brief, we consider several public health policy interventions that affect black girls' nutritional intake across the life course, particularly during childhood and adolescence.
Kiarri Kershaw, Sandra Albrecht & Mercedes Carnethon
American Journal of Epidemiology, forthcoming
We used cross-sectional data on 2,660 black and 2,611 Mexican-American adult participants in the National Health and Nutrition Examination Survey (1999-2006) to investigate the association between metropolitan-level racial/ethnic residential segregation and obesity and to determine whether it was mediated by the neighborhood socioeconomic environment. Residential segregation was measured using the black and Hispanic isolation indices. Neighborhood poverty and negative income incongruity were assessed as mediators. Multilevel Poisson regression with robust variance estimates was used to estimate prevalence ratios. There was no relationship between segregation and obesity among men. Among black women, in age-, nativity-, and metropolitan demographic-adjusted models, high segregation was associated with a 1.29 (95% confidence interval (CI): 1.00, 1.65) times higher obesity prevalence than was low segregation; medium segregation was associated with a 1.35 (95% CI: 1.07, 1.70) times higher obesity prevalence. Mexican-American women living in high versus low segregation areas had a significantly lower obesity prevalence (prevalence ratio, 0.54; 95% CI: 0.33, 0.90), but there was no difference between those living in medium versus low segregation areas. These associations were not mediated by neighborhood poverty or negative income incongruity. These findings suggest variability in the interrelationships between residential segregation and obesity for black and Mexican-American women.
Journal of Biosocial Science, forthcoming
During famines females generally have a mortality advantage relative to males, and the highest levels of mortality occur in the very young and the elderly. One popular hypothesis is that the sex differential in mortality may reflect the greater body fatness combined with lower metabolism of females, which may also underpin the age-related patterns of mortality among adults. This study evaluated the ‘body fat' hypothesis using a previously published and validated mathematical model of survival during total starvation. The model shows that at a given body weight females would indeed be expected to survive considerably longer than males in the absence of food. At a mass of 70 kg for example a female aged 30 would survive for 144 days compared with life expectancy of only 95 days for a male of the same age and weight. This effect is contributed to by both the higher body fatness and lower metabolism of the females at a given body weight. However, females are generally smaller than males and in addition to a sex effect there was also a major effect of body size - heavier individuals survive longer. When this body size effect was removed by considering survival in relation to BMI the sex effect was much reduced, and could be offset by a relatively small difference in pre-famine BMI between the sexes. Nevertheless, combining these predictions with observed mean BMIs of males and females across 48 countries at the low end of the obesity spectrum suggests that in the complete absence of food females would survive on average about 40% longer (range 6 to 64.5%) than males. The energy balance model also predicted that older adult individuals should survive much longer than younger adult individuals, by virtue of their lower resting metabolic rates and lower activity levels. Observations of the female survival advantage in multiple famines span a much wider range than the model prediction (5% to 210%). This suggests in some famines body fatness may be a significant factor influencing the mortality differential between the sexes, but in other famines other factors are likely to be more important. Moreover, the pattern of mortality in relation to age is completely opposite that predicted. These data emphasize the complex nature of famine mortality and suggest that a simple model of energy utilization alone is inadequate to explain the major aspects of this phenomenon.
Elizabeth Dao et al.
PLoS ONE, January 2013
Objectives: To investigate the independent contribution of change in sub-total body fat and lean mass to cognitive performance, specifically the executive processes of selective attention and conflict resolution, in community-dwelling older women.
Methods: This secondary analysis included 114 women aged 65 to 75 years old. Participants were randomly allocated to once-weekly resistance training, twice-weekly resistance training, or twice-weekly balance and tone training. The primary outcome measure was the executive processes of selective attention and conflict resolution as assessed by the Stroop Test. Sub-total body fat and lean mass were measured by dual-energy x-ray absorptiometry (DXA) to determine the independent association of change in both sub-total body fat and sub-total body lean mass with Stroop Test performance at trial completion.
Results: A multiple linear regression model showed reductions in sub-total body fat mass to be independently associated with better performance on the Stroop Test at trial completion after accounting for baseline Stroop performance, age, baseline global cognitive state, baseline number of comorbidities, baseline depression, and experimental group. The total variance explained was 39.5%; change in sub-total body fat mass explained 3.9% of the variance. Change in sub-total body lean mass was not independently associated with Stroop Test performance (P>0.05).
Conclusion: Our findings suggest that reductions in sub-total body fat mass - not sub-total lean mass - is associated with better performance of selective attention and conflict resolution.
Christy Turer, Hua Lin & Glenn Flores
Pediatrics, January 2013, Pages e152 -e161
Objective: Adequate vitamin D is essential for skeletal health in developing children. Although excess body weight is associated with risk of vitamin D deficiency, the national prevalence of and risk factors associated with vitamin D deficiency in overweight and obese children are unknown.
Methods: The prevalence of vitamin D deficiency (defined as 25-hydroxyvitamin-D <20 ng/mL) was determined in a sample of 6- to 18-year-old children who were enrolled in a cross-sectional study (the 2003-2006 National Health and Nutrition Examination Survey) in which body weight and height were measured directly. Children were classified as healthy-weight, overweight, obese, or severely obese by using recommended age- and gender-specificBMI-percentile cut points. Associations between BMI-percentile classification and vitamin D deficiency were examined after adjustment for relevant confounders. Sample weights were used to generate nationally representative estimates.
Results: The prevalence of vitamin D deficiency in healthy-weight, overweight, obese, and severely obese children was 21% (20%-22%), 29% (27%-31%), 34% (32%-36%), and 49% (45%-53%), respectively. The prevalence of vitamin D deficiency in severely obese white, Latino, and African-American children was 27% (3%-51%), 52% (36%-68%), and 87% (81%-93%), respectively. Compared with healthy-weight children, overweight, obese, and severely obese children had significantly greater adjusted odds of vitamin D deficiency. Modifiable factors associated with vitamin D deficiency in overweight/obese children were identified.
Conclusions: Vitamin D deficiency is highly prevalent in overweight and obese children. The particularly high prevalence in severely obese and minority children suggests that targeted screening and treatment guidance is needed.
Peter James et al.
American Journal of Public Health, February 2013, Pages 369-375
Objectives: We evaluated the association between the county sprawl index, a measure of residential density and street accessibility, and physical activity and body mass index (BMI).
Methods: We conducted a multilevel cross-sectional analysis in a sample of Nurses' Health Study participants living throughout the United States in 2000 to 2001 (n = 136 592).
Results: In analyses adjusted for age, smoking status, race, and husband's education, a 1-SD (25.7) increase in the county sprawl index (indicating a denser, more compact county) was associated with a 0.13 kilograms per meters squared (95% confidence interval [CI] = -0.18, -0.07) lower BMI and 0.41 (95% CI = 0.17, 0.65) more metabolic equivalent (MET) hours per week of total physical activity, 0.26 (95% CI = 0.19, 0.33) more MET hours per week of walking, and 0.47 (95% CI = 0.34, 0.59) more MET hours per week of walking, bicycling, jogging, and running. We detected potential effect modification for age, previous disease status, husband's education level (a proxy for socioeconomic status), and race.
Conclusions: Our results suggest that living in a dense, compact county may be conducive to higher levels of physical activity and lower BMI in women.
Dayna Alexander et al.
Journal of Epidemiology & Community Health, forthcoming
Background: Despite the rising childhood obesity rates, few studies have examined the association between access to recreational parks and facilities and obesity.
Methods: A cross-sectional study was performed among 42 278 US children who participated in the 2007 National Survey of Children's Health. Access to parks and recreational facilities was self-reported by parents, and body mass index was calculated from parents' self-report of the child's height and weight. Logistic regression was used to obtain ORs and 95% CIs. Since obesity was not a rare occurrence, an OR correction method was used to provide a more reliable estimate of the prevalence ratio (PR).
Results: Children with access to parks and facilities had decreased prevalence of obesity as compared to children without access (PR=0.79, 95% CI 0.69 to 0.91). After adjustment for covariates, the magnitude of the association remained unchanged; however, results were no longer statistically significant (PR=0.77, 95% CI 0.55 to 1.07). Race/ethnicity was an effect modifier of the access-obesity relationship (p<0.0001). Among Non-Hispanic White children, there was no strong association (PR=0.89, 95% CI 0.64 to 1.23). However, among Non-Hispanic Black children, those who had access to recreational parks and facilities had 0.40 times the prevalence of obesity as compared to those without access, and this result was statistically significant (95% CI 0.17 to 0.90).
Conclusions: This research highlights potential health disparities in childhood obesity due to limited access to recreational parks and facilities. Additional studies are needed to further investigate this association. If confirmed, providing safe, accessible parks and facilities may be one way to combat childhood obesity, particularly among minority children.
Antonio Terracciano et al.
PLoS ONE, January 2013
Personality traits and cardiorespiratory fitness in older adults are reliable predictors of health and longevity. We examined the association between personality traits and energy expenditure at rest (basal metabolic rate) and during normal and maximal sustained walking. Personality traits and oxygen (VO2) consumption were assessed in 642 participants from the Baltimore Longitudinal Study of Aging. Results indicate that personality traits were mostly unrelated to resting metabolic rate and energy expenditure at normal walking pace. However, those who scored lower on neuroticism (r = -0.12) and higher on extraversion (r = 0.11), openness (r = 0.13), and conscientiousness (r = 0.09) had significantly higher energy expenditure at peak walking pace. In addition to greater aerobic capacity, individuals with a more resilient personality profile walked faster and were more efficient in that they required less energy per meter walked. The associations between personality and energy expenditure were not moderated by age or sex, but were in part explained by the proportion of fat mass. In conclusion, differences in personality may matter the most during more challenging activities that require cardiorespiratory fitness. These findings suggest potential pathways that link personality to health outcomes, such as obesity and longevity.
M. Garaulet et al.
International Journal of Obesity, forthcoming
Background: There is emerging literature demonstrating a relationship between the timing of feeding and weight regulation in animals. However, whether the timing of food intake influences the success of a weight-loss diet in humans is unknown.
Objective: To evaluate the role of food timing in weight-loss effectiveness in a sample of 420 individuals who followed a 20-week weight-loss treatment.
Methods: Participants (49.5% female subjects; age (mean±s.d.): 42±11 years; BMI: 31.4±5.4 kg m-2) were grouped in early eaters and late eaters, according to the timing of the main meal (lunch in this Mediterranean population). 51% of the subjects were early eaters and 49% were late eaters (lunch time before and after 1500 hours, respectively), energy intake and expenditure, appetite hormones, CLOCK genotype, sleep duration and chronotype were studied.
Results: Late lunch eaters lost less weight and displayed a slower weight-loss rate during the 20 weeks of treatment than early eaters (P=0.002). Surprisingly, energy intake, dietary composition, estimated energy expenditure, appetite hormones and sleep duration was similar between both groups. Nevertheless, late eaters were more evening types, had less energetic breakfasts and skipped breakfast more frequently that early eaters (all; P<0.05). CLOCK rs4580704 single nucleotide polymorphism (SNP) associated with the timing of the main meal (P=0.015) with a higher frequency of minor allele (C) carriers among the late eaters (P=0.041). Neither sleep duration, nor CLOCK SNPs or morning/evening chronotype was independently associated with weight loss (all; P>0.05).
Conclusions: Eating late may influence the success of weight-loss therapy. Novel therapeutic strategies should incorporate not only the caloric intake and macronutrient distribution - as is classically done - but also the timing of food.
Allan Geliebter et al.
Behavioural Brain Research, 15 April 2013, Pages 91-96
Gender specific effects on human eating have been previously reported. Here we investigated sex-based differences in neural activation via whole-brain blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in response to high energy-dense (high-ED) vs. low-ED visual and auditory food cues in obese men vs. women in both fed and fasted states. The results show that in response to high vs. low ED foods in the fed state, obese men (vs. women), had greater activation in brain areas associated with motor control regions (e.g. supplementary motor areas) whereas women showed greater activation in cognitive-related regions. When fasted, obese men had greater activation in a visual-attention region whereas obese women showed greater activation in affective and reward related processing regions (e.g. caudate). Overall the results support our a priori hypothesis that obese women (vs. men) have greater neural activation in regions associated with cognition and emotion-related brain regions. These findings may improve our understanding of sex specific differences among obese individuals in eating behavior.
Pierre Dubois, Rachel Griffith & Aviv Nevo
NBER Working Paper, February 2013
Food purchases differ substantially across countries. We use detailed household level data from the US, France and the UK to (i) document these differences; (ii) estimate a demand system for food and nutrients, and (iii) simulate counterfactual choices if households faced prices and nutritional characteristics from other countries. We find that differences in prices and characteristics are important and can explain some difference (e.g., US-France difference in caloric intake), but generally cannot explain many of the compositional patterns by themselves. Instead, it seems an interaction between the economic environment and differences in preferences is needed to explain cross country differences.
Steffen Nestler & Boris Egloff
Social Psychology, Winter 2013, Pages 26-32
In a job context, we investigated whether controllability of a stigma influences the self-protective effects of attributions to discrimination. Eighty overweight females read a vignette and imagined being rejected for a job because of their (1) personal abilities, (2) sex, (3) being overweight due to a disease, or (4) being overweight from personal causes. Results showed that when the rejection was gender-based, participants blamed themselves less and had higher performance self-esteem than when it was due to personal abilities. Importantly, when being overweight had a personal background - and was hence controllable - women blamed themselves more for the rejection and reported lower performance self-esteem than did participants in the overweight condition with a disease background. The results support the dependency of self-protective effects of discrimination attributions on controllability.
Kerry Anne McGeary
Social Science & Medicine, forthcoming
Currently, there is insufficient evidence regarding which policies will improve nutrition, reduce BMI levels and the prevalence of obesity and overweight nationwide. This preliminary study investigates the impact of a nutrition-education policy relative to price policy as a means to reduce BMI in the United States (US). Model estimations use pooled cross-sectional data at the individual-level from the Centers for Disease Control's (CDC), Behavioral Risk Factor Surveillance System (BRFSS), state-level food prices from the American Chamber of Commerce Research Association (ACCRA) and funding for state-specific nutrition-education programs from the United States Department of Agriculture (USDA) from 1992 - 2006. The total number of observations for the study is 2,249,713 over 15 years. During this period, federal funding for state-specific nutrition-education programs rose from approximately $660 thousand for seven states to nearly $248 million for all fifty-two states. In 2011, federal funding for nutrition-education programs reached $375 million. After controlling for state fixed effects, year effects and state specific linear and quadratic time trends, we find that nutrition education spending has the intended effect on BMI, obese and overweight in aggregate. However, we find heterogeneity as individuals from certain, but not all, income and education-levels respond to nutrition-education funding. The results regarding nutrition-education programs suggest that large scale funding of nutrition education programs may improve BMI-levels and reduce obesity and overweight. However, more study is required to determine if these funds are able make the requisite dietary improvements that may ultimately improve BMI for individuals from low income and education-levels.