Food prices and weight gain during elementary school: 5-year update

Neighborhood and Behavioral Effects on Weight Change Across Immigrant Generations: Evidence from the National Longitudinal Study of Adolescent to Adult Health (Add Health)

BACKGROUND

Childhood obesity is a global problem that disproportionately affects minority populations in the USA. Relative to all US-born individuals, some foreign-born populations also experience higher obesity risk. Prior research focuses on the role of healthy behaviors in increasing obesity risk, but the neighborhoods in which individuals reside shape those behaviors. The aim of this study is to examine how changes in health behaviors and neighborhood characteristics affect weight change across immigrant generational groups.

METHODS

The study uses a prospective longitudinal cohort of 3,506 adolescents first interviewed in 1994 (The National Longitudinal Study of Adolescent to Adult Health). To examine the relationship between immigrant generational status and weight change over time while considering healthy behaviors and the neighborhood environment, this research relies on linear multilevel methods.

RESULTS

Neighborhood disadvantage, not health behaviors, has a significant effect on weight change - for both first-generation Asians (β = 1.52; p < 0.001) and Latinxs across all immigrant generations. In neighborhoods where residents do not engage in much exercise, the role that one's level of physical activity plays in weight change is lower than in places where residents engage in much exercise, irrespective of immigrant generation.

CONCLUSION

These findings provide some evidence that neighborhood features and physical activity in the neighborhood may curb obesity risk among adolescents and young adults. The results can inform urban planning efforts and community-based interventions to increase physical activity across ethnic minority populations.

Sugar-Sweetened Beverage, Obesity, and Type 2 Diabetes in Children and Adolescents: Policies, Taxation, and Programs

PURPOSE OF REVIEW

Obesity has grown at an alarming rate in children and adolescents. Concurrently, consumption on sugar-sweetened beverages (SSBs) also rose significantly. This review provides an overview of obesity and type 2 diabetes mellitus (T2DM) related to SSBs and current policies restricting SSBs in schools, school-based interventions, and taxation on reducing SSB intake and obesity. We also discuss challenges of and future steps for these initiatives.

RECENT FINDINGS

Clinical and epidemiological studies suggest a strong association between SSB intake and obesity and T2DM. School food policies have been initiated at federal, state, and local levels. School-based interventions have shown positive effects on SSB intake and obesity reduction. Taxation on SSBs is promising in combating obesity and in generating revenue. Challenges towards compliance and implementation of the policies and programs exist. The relationship between SSB and obesity and T2DM is a complex problem which requires comprehensive solutions. Continued efforts in restricting SSBs in schools are needed. Intervention programs should be tailored to age, gender, language, and culture and involve participation from families and local communities. Taxation can reduce SSB consumption by direct economic incentive, earmarking revenues to support healthy foods, and sending negative message. However, a higher tax rate may be necessary to have a measurable effect on weight.

Health-equity issues related to childhood obesity: a scoping review

PURPOSE

The purpose of this scoping review was to determine the health-equity issues that relate to childhood obesity.

METHODS

Health-equity issues related to childhood obesity were identified by analyzing food environment, natural and built environment, and social environment. The authors searched Medline, PubMed, and Web of Science, using the keywords "children" and "obesity." Specific terms for each environment were added: "food desert," "advertising," "insecurity," "price," "processing," "trade," and "school" for food environment; "urban design," "land use," "transportation mode," "public facilities," and "market access" for natural and built environment; and "financial capacity/poverty," "living conditions," "transport access," "remoteness," "social support," "social cohesion," "working practices," "eating habits," "time," and "social norms" for social environment. Inclusion criteria were studies or reports with populations under age 12, conducted in the United States, and published in English in 2005 or later.

RESULTS

The final search yielded 39 references (16 for food environment, 11 for built environment, and 12 for social environment). Most food-environment elements were associated with obesity, except food insecurity and food deserts. A natural and built environment that hinders access to physical activity resources and access to healthy foods increased the risk of childhood obesity. Similarly, a negative social environment was associated with childhood obesity. More research is needed on the effects of food production, living conditions, time for shopping, and exercise, as related to childhood obesity.

CONCLUSIONS

Most elements of food, natural and built, and social-environments were associated with weight in children under age 12, except food insecurity and food deserts.

Effect of Meat Price on Race and Gender Disparities in Obesity, Mortality and Quality of Life in the US: A Model-Based Analysis

INTRODUCTION

There are large differences in the burden and health implications of obesity by race and gender in the US. It is unclear to what extent policies modifying caloric consumption change the distribution of the burden of obesity and related health outcomes. Meat is a large component of the American diet. We investigate how changing meat prices (that may result from policies or from exogenous factors that reduce supply) might impact the burden of obesity by race and gender.

METHODS

We construct a microsimulation model that evaluates the 15-year body-mass index (BMI) and mortality impact of changes in meat price (5, 10, 25, and 50% increase) in the US adult population stratified by age, gender, race, and BMI.

RESULTS

Under each price change evaluated, relative to the status quo, white males, black males, and black females are expected to realize more dramatic reduction in 2030 obesity prevalence than white females. Life expectancy gains are also projected to differ by subpopulation, with black males far less likely to benefit from an increase in meat prices than other groups.

CONCLUSIONS

Changing meat prices has considerable potential to affect population health differently by race and gender. In designing interventions that alter the price of foods to consumers, it is not sufficient to assess health effects based solely on the population as a whole, since differential effects across subpopulations may be substantial.

Walkable home neighbourhood food environment and children's overweight and obesity: Proximity, density or price?

OBJECTIVES

To identify characteristics of the food environment associated with child overweight/obesity that could, if subjected to intervention, mitigate the risk of childhood overweight/obesity. We examined whether the proximity to or density of grocery and convenience stores or fast food restaurants, or the prices of healthy food options were more strongly associated with overweight/obesity risk in children.

METHODS

We collected geocoded data by residential addresses for 1,469 children aged 10-14 years and conducted a census of all food outlets in Saskatoon. The Nutrition Environment Measures Survey (NEMS)-Stores and the NEMS-Restaurants were used to measure availability, quality and relative price of healthy food items in stores and restaurants. Children's weight status was calculated on the basis of measured height and weight. Logistic regression was used to test the associations between overweight/obesity and food environment variables.

RESULTS

Within an 800 m walking distance from home, 76% of children did not have access to a grocery store; 58% and 32% had access to at least one convenience store or one fast-food restaurant respectively. A significantly lower odds of overweight/obesity was associated with lower price of healthy food items/options in grocery stores (odds ratio [OR] = 0.87, 95% confidence interval [CI] 0.77-0.99) and fast-food restaurants (OR = 0.97, 95% CI 0.95-0.99) within walking distance of home. Neither the distance to the closest food outlet nor the density of food outlets around children's homes was associated with odds of overweight/obesity.

CONCLUSIONS

Improving economic access to healthy food in food outlets or fast-food restaurants is one strategy to counter childhood overweight/ obesity.

Impact of the removal of chocolate milk from school milk programs for children in Saskatoon, Canada

Studies in the United States report inclusion of flavoured milk in the diets of children and youth improves nutrient intakes. No research has investigated the contribution of flavoured milk to overall milk intake or the milk preferences of Canadian children. The objective of the study was to measure milk consumption (plain milk and flavoured milk) by children in an elementary school environment and investigate factors contributing to milk choice. A mixed-method research design was applied across 6 schools for 12 weeks. Milk waste was measured in grades 1–8 for 12 weeks. Weeks 1–4 (phase 1) and 9–12 (phase 3) provided both plain milk and flavoured milk as chocolate milk while weeks 5–8 (phase 2) provided plain milk only. Beverage Frequency Questionnaires were used in each phase (in grades 5–8 only) to assess usual beverage consumption. Statistical nutrient modelling was conducted to determine the effects of removing chocolate milk during phase 2 as a milk choice. Later, focus groups were conducted with students in grades 5–8 to determine what influences them to choose/not choose to drink milk. Total milk intake decreased by 12.3% when chocolate milk was removed from the schools (26.6% ± 5.2% to 14.31% ± 1.6%, p < 0.001). Milk choice was influenced by environmental factors as well as taste, cost, convenience, and variety. Total milk intake was associated with location (p = 0.035) and cost (p < 0.001), with rural students and/or those students receiving free milk drinking the greatest amount of milk. Nutrient modelling revealed chocolate milk is more cost-efficient and convenient at providing nutrients than alternative food/drink combinations.

Empirical evidence of the efficiency and efficacy of fat taxes and thin subsidies

This study summarizes the empirical literature on fat taxes and thin subsidies to assess their efficiency and efficacy as instruments of public policy to control obesity. Three specific types of taxes are studied in the literature: food group taxes; nutrient taxes; and nutrient index taxes. Anumber of studies use food expenditure data to assess the impact of various taxes on obesity and therefore only indirectly measure the impacts of taxes and subsidies on obesity. These studies generally conclude that food group taxes, nutrient taxes and nutrient index taxes have a small impact on the purchases of food and the nutrients purchased. Other studies use the body mass index as the explanatory variable and thus measure the impacts of taxes on body mass index directly. Nutrient taxes are found to be more effective than food group taxes, although even for nutrient taxes, the effects are small. In general, thin subsidies seem to offer more effective control of obesity than obesity taxes. However, due to the small effects of both fat taxes and thin subsidies, they are not recommended as instruments of food and nutrition policy.

Relative food prices and obesity in US Metropolitan areas: 1976-2001

This study investigates the impact of food price on obesity, by exploring the co-occurrence of obesity growth with relative food price reduction between 1976 and 2001. Analyses control for female labor participation and metropolitan outlet densities that might affect body weight. Both the first-difference and fixed effects approaches provide consistent evidence suggesting that relative food prices have substantial impacts on obesity and such impacts were more pronounced among the low-educated. These findings imply that relative food price reductions during the time period could plausibly explain about 18% of the increase in obesity among the U.S. adults in metropolitan areas.

Obesity and economic environments

This review summarizes current understanding of economic factors during the obesity epidemic and dispels some widely held, but incorrect, beliefs. Rising obesity rates coincided with increases in leisure time (rather than increased work hours), increased fruit and vegetable availability (rather than a decline in healthier foods), and increased exercise uptake. As a share of disposable income, Americans now have the cheapest food available in history, which fueled the obesity epidemic. Weight gain was surprisingly similar across sociodemographic groups or geographic areas, rather than specific to some groups (at every point in time; however, there are clear disparities). It suggests that if one wants to understand the role of the environment in the obesity epidemic, one needs to understand changes over time affecting all groups, not differences between subgroups at a given time. Although economic and technological changes in the environment drove the obesity epidemic, the evidence for effective economic policies to prevent obesity remains limited. Taxes on foods with low nutritional value could nudge behavior toward healthier diets, as could subsidies/discounts for healthier foods. However, even a large price change for healthy foods could close only part of the gap between dietary guidelines and actual food consumption. Political support has been lacking for even moderate price interventions in the United States and this may continue until the role of environmental factors is accepted more widely. As opinion leaders, clinicians play an important role in shaping the understanding of the causes of obesity.

Local food prices and their associations with children's weight and food security

OBJECTIVES

Both obesity and food insecurity are important public health problems facing young children in the United States. A lack of affordable, healthy foods is one of the neighborhood factors presumed to underlie both food insecurity and obesity among children. We examine associations between local food prices and children's BMI, weight, and food security outcomes.

METHODS

We linked data from the Early Childhood Longitudinal Study-Birth Cohort, a nationally representative study of children from infancy to age 5, to local food price data from the Council for Community and Economic Research (C2ER) Cost-of-Living Index (n = 11,700 observations). Using ordinary least squares (OLS), linear probability, and within-child fixed effects (FE) models, we exploit the variability in food price data over time and among children who move residences focusing on a subsample of households under 300% of the Federal Poverty Level.

RESULTS

Results from ordinary least squares and FE models indicate that higher-priced fruits and vegetables are associated with higher child BMI, and this relationship is driven by the prices of fresh (versus frozen or canned) fruits and vegetables. In the FE models, higher-priced soft drinks are associated with a lower likelihood of being overweight, and surprisingly, higher fast food prices are associated with a greater likelihood of being overweight.

CONCLUSIONS

Policies that reduce the costs of fresh fruits and vegetables may be effective in promoting healthy weight outcomes among young children.

Taxing junk food to counter obesity

We examined the advantages and disadvantages of implementing a junk food tax as an intervention to counter increasing obesity in North America. Small excise taxes are likely to yield substantial revenue but are unlikely to affect obesity rates. High excise taxes are likely to have a direct impact on weight in at-risk populations but are less likely to be politically palatable or sustainable. Ultimately, the effectiveness of earmarked health programs and subsidies is likely to be a key determinant of tax success in the fight against obesity.

Simulation modeling of policies directed at youth sugar-sweetened beverage consumption

Childhood obesity is a significant public health problem requiring innovative solutions. While recent reviews indicate that some policies show promise, there is a lack of information regarding which policies, and policy combinations, work best. Low-nutrition, energy-dense foods and beverages such as sugar-sweetened beverages (SSBs) have been identified as a major contributor to the problem. The purpose of this paper is to use simulation modeling to show how changes in three categories of SSB policies-school nutrition, school-based education, and taxes-impact SSB and other food consumption. The model shows that policies directed at SSBs, particularly tax hikes, could lead to substantial reductions in the number of calories consumed by youth. The estimates, however, are subject to a high degree of uncertainty. Estimates from school-based nutrition and school-based education policies, while also helping to reduce caloric intake, generally show smaller effects than tax policies and considerable variation around parameter estimates for individual and combined policies. We conclude with a discussion of the limits of the model, and suggest where additional information is needed. Limitations notwithstanding, simulation modeling is a promising methodology that can help advance our understanding of policy effects, thereby helping policymakers to better formulate effective policies to reduce obesity prevalence and the associated social harms.

Assessing the potential effectiveness of food and beverage taxes and subsidies for improving public health: a systematic review of prices, demand and body weight outcomes

Taxes and subsidies are increasingly being considered as potential policy instruments to incentivize consumers to improve their food and beverage consumption patterns and related health outcomes. This study provided a systematic review of recent U.S. studies on the price elasticity of demand for sugar-sweetened beverages (SSBs), fast food, and fruits and vegetables, as well as the direct associations of prices/taxes with body weight outcomes. Based on the recent literature, the price elasticity of demand for SSBs, fast food, fruits and vegetables was estimated to be -1.21, -0.52, -0.49 and -0.48, respectively. The studies that linked soda taxes to weight outcomes showed minimal impacts on weight; however, they were based on existing state-level sales taxes that were relatively low. Higher fast-food prices were associated with lower weight outcomes particularly among adolescents, suggesting that raising prices would potentially impact weight outcomes. Lower fruit and vegetable prices were generally found to be associated with lower body weight outcomes among both low-income children and adults, suggesting that subsidies that would reduce the cost of fruits and vegetables for lower-socioeconomic populations may be effective in reducing obesity. Pricing instruments should continue to be considered and evaluated as potential policy instruments to address public health risks.

Measures of the consumer food store environment: a systematic review of the evidence 2000-2011

Description of the consumer food environment has proliferated in publication. However, there has been a lack of systematic reviews focusing on how the consumer food environment is associated with the following: (1) neighborhood characteristics; (2) food prices; (3) dietary patterns; and (4) weight status. We conducted a systematic review of primary, quantitative, observational studies, published in English that conducted an audit of the consumer food environment. The literature search included electronic, hand searches, and peer-reviewed from 2000 to 2011. Fifty six papers met the inclusion criteria. Six studies reported stores in low income neighborhoods or high minority neighborhoods had less availability of healthy food. While, four studies found there was no difference in availability between neighborhoods. The results were also inconsistent for differences in food prices, dietary patterns, and weight status. This systematic review uncovered several key findings. (1) Systematic measurement of determining availability of food within stores and store types is needed; (2) Context is relevant for understanding the complexities of the consumer food environment; (3) Interventions and longitudinal studies addressing purchasing habits, diet, and obesity outcomes are needed; and (4) Influences of price and marketing that may be linked with why people purchase certain items.

Socioeconomic status and the health of youth: a multilevel, multidomain approach to conceptualizing pathways

Previous research has clearly established associations between low socioeconomic status (SES) and poor youth physical health outcomes. This article provides an overview of the main pathways through which low SES environments come to influence youth health. We focus on 2 prevalent chronic health problems in youth today, asthma and obesity. We review and propose a model that encompasses (a) multiple levels of influence, including the neighborhood, family and person level; (b) both social and physical domains in the environment; and finally (c) dynamic relationships between these factors. A synthesis of existing research and our proposed model draw attention to the notion of adverse physical and social exposures in youth's neighborhood environments altering family characteristics and youth psychosocial and behavioral profiles, thereby increasing youth's risk for health problems. We also note the importance of acknowledging reciprocal influences across levels and domains (e.g., between family and child) that create self-perpetuating patterns of influence that further accentuate the impact of these factors on youth health. Finally, we document that factors across levels can interact (e.g., environmental pollution levels with child stress) to create unique, synergistic effects on youth health. Our model stresses the importance of evaluating influences on youth's physical health not in isolation but in the context of the broader social and physical environments in which youth live. Understanding the complex relationships between the factors that link low SES to youth's long-term health trajectories is necessary for the creation and implementation of successful interventions and policies to ultimately reduce health disparities.

Retail grocery store marketing strategies and obesity: an integrative review

CONTEXT

In-store food marketing can influence food-purchasing behaviors and warrants increased attention given the dramatic rise in obesity. Descriptive and experimental studies of key marketing components have been conducted by consumer scientists, marketing researchers, and public health experts. This review synthesizes research and publications from industry and academic sources and provides direction for developing and evaluating promising interventions.

EVIDENCE ACQUISITION

Literature sources for the review were English-language articles published from 1995 to 2010, identified from multidisciplinary search indexes, backward searches of cited articles, review articles, industry reports, and online sources. Only articles that focused on physical grocery stores and food products were included. Data collection occurred in 2010 and 2011.

EVIDENCE SYNTHESIS

Articles were classified in the categories of product, price, placement, and promotion and divided into controlled laboratory experiments, observation, and field experiments; 125 primary peer-reviewed articles met the inclusion criteria. Narrative synthesis methods were used. Key findings were synthesized by category of focus and study design. Evidence synthesis was completed in 2011.

CONCLUSIONS

Findings suggest several strategies for in-store marketing to promote healthful eating by increasing availability, affordability, prominence, and promotion of healthful foods and/or restricting or de-marketing unhealthy foods. Key results of research in controlled laboratory studies should be adapted and tested in real-world in-store settings. Industry methods for assessing consumer behavior, such as electronic sales data and individually linked sales information from loyalty card holders, can help public health researchers increase the scientific rigor of field studies.

Improving nutrition in home child care: are food costs a barrier?

OBJECTIVE

Child-care providers have a key role to play in promoting child nutrition, but the higher cost of nutritious foods may pose a barrier. The present study tested the hypothesis that higher nutritional quality of foods served was associated with higher food expenditures in child care homes participating in the Child and Adult Care Food Program (CACFP).

DESIGN

In this cross-sectional study, nutritional quality of foods served to children and food expenditures were analysed based on 5 d menus and food shopping receipts. Nutritional quality was based on servings of whole grains, fresh whole fruits and vegetables, energy density (kJ/g) and mean nutrient adequacy (mean percentage of dietary reference intake) for seven nutrients of concern for child health. Food expenditures were calculated by linking receipt and menu data. Associations between food expenditures and menu quality were examined using bivariate statistics and multiple linear regression models.

SETTING

USA in 2008-2009.

SUBJECTS

Sixty child-care providers participating in CACFP in King County, Washington State.

RESULTS

In bivariate analyses, higher daily food expenditures were associated with higher total food energy and higher nutritional quality of menus. Controlling for energy and other covariates, higher food expenditures were strongly and positively associated with number of portions of whole grains and fresh produce served (P = 0·001 and 0·005, respectively), with lower energy density and with higher mean nutrient adequacy of menus overall (P = 0·003 and 0·032, respectively).

CONCLUSIONS

The results indicate that improving the nutritional quality of foods in child care may require higher food spending.

Economic instruments for obesity prevention: results of a scoping review and modified Delphi survey

BACKGROUND

Comprehensive, multi-level approaches are required to address obesity. One important target for intervention is the economic domain. The purpose of this study was to synthesize existing evidence regarding the impact of economic policies targeting obesity and its causal behaviours (diet, physical activity), and to make specific recommendations for the Canadian context.

METHODS

Arksey and O'Malley's (2005) methodological framework for conducting scoping reviews was adopted for this study and this consisted of two phases: 1) a structured literature search and review, and 2) consultation with experts in the research field through a Delphi survey and an in-person expert panel meeting in April 2010.

RESULTS

Two key findings from the scoping review included 1) consistent evidence that weight outcomes are responsive to food and beverage prices. The debate on the use of food taxes and subsidies to address obesity should now shift to how best to address practical issues in designing such policies; and 2) very few studies have examined the impact of economic instruments to promote physical activity and clear policy recommendations cannot be made at this time. Delphi survey findings emphasised the relatively modest impact any specific economic instrument would have on obesity independently. Based on empirical evidence and expert opinion, three recommendations were supported. First, to create and implement an effective health filter to review new and current agricultural polices to reduce the possibility that such policies have a deleterious impact on population rates of obesity. Second, to implement a caloric sweetened beverage tax. Third, to examine how to implement fruit and vegetable subsidies targeted at children and low income households.

CONCLUSIONS

In terms of economic interventions, shifting from empirical evidence to policy recommendation remains challenging. Overall, the evidence is not sufficiently strong to provide clear policy direction. Additionally, the nature of the experiments needed to provide definitive evidence supporting certain policy directions is likely to be complex and potentially unfeasible. However, these are not reasons to take no action. It is likely that policies need to be implemented in the face of an incomplete evidence base.

Regional price differences and food consumption frequency among elementary school children

OBJECTIVE

Food prices may affect diet and weight gain among youth and lead to geographic disparities in obesity. This paper examines the association between regional prices and consumption frequency of fruit/vegetables and snack items among elementary school children in the USA.

STUDY DESIGN

Observational study using individual-level survey data of fifth-grade children (average age 11 years) and regional food prices based on store visits in 2004.

METHODS

Dependent variables are self-reported consumption frequency in fifth grade; primary explanatory variables are metropolitan area food prices relative to cost of living. Multivariate regression analysis.

RESULTS

Price variation across metropolitan areas exists, and lower real prices for vegetables and fruits predict significantly higher intake frequency. Higher dairy prices predict lower frequency of milk consumption, while higher meat prices predict increased milk consumption. Similar price effects were not found for fast food or soft drink consumption.

DISCUSSION

The geographic variation in food prices across the USA is sufficiently large to affect dietary patterns among youth for fruit, vegetables and milk. The price variation is either too small to affect children's consumption frequency of fast food or soft drinks, or the consumption of these foods is less price sensitive.

Simulation models of obesity: a review of the literature and implications for research and policy

Simulation models (SMs) combine information from a variety of sources to provide a useful tool for examining how the effects of obesity unfold over time and impact population health. SMs can aid in the understanding of the complex interaction of the drivers of diet and activity and their relation to health outcomes. As emphasized in a recently released report of the Institute or Medicine, SMs can be especially useful for considering the potential impact of an array of policies that will be required to tackle the obesity problem. The purpose of this paper is to present an overview of existing SMs for obesity. First, a background section introduces the different types of models, explains how models are constructed, shows the utility of SMs and discusses their strengths and weaknesses. Using these typologies, we then briefly review extant obesity SMs. We categorize these models according to their focus: health and economic outcomes, trends in obesity as a function of past trends, physiologically based behavioural models, environmental contributors to obesity and policy interventions. Finally, we suggest directions for future research.

A review of the literature on policies directed at the youth consumption of sugar sweetened beverages

Sugar sweetened beverages (SSB) constitute a large percentage of energy consumed by youth. This paper reviews the literature on school nutrition policies and price interventions directed at youth SSB consumption. In addition to considering the direct effect of policies on SSB consumption, we provide an overview of the literature on how SSB consumption affects total energy intake (TEI) and BMI, as well as on how TEI affects BMI. By considering each of these links, we attempted to gauge the effect of policies directed at SSB consumption, as well as highlight areas that merit future research. We found that school nutrition and price policies reduce SSB consumption and that reduced SSB consumption is associated with a reduction in energy intake that can influence BMI. Policies directed at SSB consumption can play an important role in reducing youth overweight and obesity.

Effect of food prices on the prevalence of obesity among young adults

OBJECTIVE

To examine the extent to which various food prices were associated with the obesity status of young adults.

STUDY DESIGN

Retrospective cohort study of 6537 men and 5324 women in the USA using panel data from the Monitoring the Future Surveys (1992-2003), which were merged with two food-at-home and one food-away-from-home price measures from the American Chamber of Commerce Researchers Association.

METHODS

Longitudinal individual random effect and fixed effect models were estimated.

RESULTS

This study found that food prices did not have a significant effect on the prevalence of obesity among young female adults. For young adult men, an individual random effect estimator suggested that a 10% increase in the price of fast food was associated with a 13.2% decrease in the probability of obesity, but this effect lost its economic and statistical significance once individual fixed effects were controlled for in the estimation.

CONCLUSIONS

Overall, the results imply that observed time-varying individual characteristics, such as working status, marital status and school enrolment status, may over-ride the effect of changes in food prices for young adults. More research employing longitudinal data is necessary to determine if food subsidies or taxes, particularly soft drink and fast food taxes or subsidies for fruit and vegetables, could be effective policy measures to curtail the increasing prevalence of obesity among young adults.

The costs of food at home and away from home and consumption patterns among U.S. adolescents

PURPOSE

This study examined the associations of prices of food at home groceries, prices of fast food away from home and the availability of food stores and restaurants with the number of days over the past week that adolescents consumed fruit and fruit juices, vegetables, meat, nonmeat protein, dairy, grains, and sweets.

METHODS

Individual-level data on adolescents were drawn from the Child Development Supplement of the Panel Study of Income Dynamics combined at the zip code level with external economic contextual data. Multivariate regression analyses were used to estimate the associations between food consumption categories and the economic contextual factors. Regressions were also estimated by households' poverty status.

RESULTS

Fast food and food at home prices were not significantly associated with any of the food consumption categories in the full sample. However, among poor adolescents, higher fast food prices were associated with higher levels of nonmeat protein consumption. Food store outlet availability was found to have very small significant associations with some food consumption categories but no significant associations were found for restaurant outlets.

CONCLUSIONS

Food away from home prices, such as fast food prices and supermarket and grocery store availability, were associated with some food consumption categories among low-income youths and related policies deserve further examination.

Soda taxes, soft drink consumption, and children's body mass index

Taxes on sugar-sweetened beverages have been proposed to combat obesity. Using data on state sales taxes for soda and individual-level data on children, we examine whether small taxes are likely to change consumption and weight gain or whether larger tax increases would be needed. We find that existing taxes on soda, which are typically not much higher than 4 percent in grocery stores, do not substantially affect overall levels of soda consumption or obesity rates. We do find, however, that subgroups of at-risk children--children who are already overweight, come from low-income families, or are African American--may be more sensitive than others to soda taxes, especially when soda is available at school. A greater impact of these small taxes could come from the dedication of the revenues they generate to other obesity prevention efforts rather than through their direct effect on consumption.

Fast food costs and adolescent body mass index: evidence from panel data

This study draws on four waves of the 1997 National Longitudinal Survey of Youth and external data to examine the relationship between adolescent body mass index (BMI) and fast food prices and fast food restaurant availability using panel data estimation methods to account for individual-level unobserved heterogeneity. Analyses also control for contextual factors including general food prices and the availability of full-service restaurants, supermarkets, grocery stores, convenience stores and commercial physical activity-related facilities. The longitudinal individual-level fixed effects results confirm cross-sectional findings that the price of fast food but not the availability of fast food restaurants has a statistically significant effect on teen BMI with an estimated price elasticity of -0.08. The results suggest that the cross-sectional model over-estimates the price of fast food BMI effect by about 25%. There is evidence that the weight of teens in low- to middle-socioeconomic status families is most sensitive to fast food prices.

Associations between state-level soda taxes and adolescent body mass index

PURPOSE

Soft drink consumption has been linked with higher energy intake, obesity, and poorer health. Fiscal pricing policies such as soda taxes may lower soda consumption and, in turn, reduce weight among U.S. adolescents.

METHODS

This study used multivariate linear regression analyses to examine the associations between state-level grocery store and vending machine soda taxes and adolescent body mass index (BMI). We used repeated cross-sections of individual-level data on adolescents drawn from the Monitoring the Future surveys combined with state-level tax data and local area contextual measures for the years 1997 through 2006.

RESULTS

The results showed no statistically significant associations between state-level soda taxes and adolescent BMI. Only a weak economic and statistically significant effect was found between vending machine soda tax rates and BMI among teens at risk for overweight.

CONCLUSIONS

Current state-level tax rates are not found to be significantly associated with adolescent weight outcomes. It is likely that taxes would need to be raised substantially to detect significant associations between taxes and adolescent weight.

Affordability and Obesity: Issues in the Multifunctionality of Agricultural/Food Systems

The conference discussed public goods and externalities created as byproducts of the food system, including local development, obesity, air and water pollution, climate change, antibiotic resistance, and other public health issues. Multifunctionality is a framework that integrates these diverse issues and has been influential in international policy. This commentary focuses on arguably the most prominent public health issue at the moment: obesity. While obesity could be considered another multifunctional dimension, its link to other conference topics are tenuous. Using obesity as an argument to promote local produce or achieve other multifunctional outcomes is very questionable. Framing obesity as an issue of poverty or food insecurity trivializes the continuing major problem of hunger worldwide.

Food prices and obesity: evidence and policy implications for taxes and subsidies

CONTEXT

Pricing policies have been posited as potential policy instruments to address the increasing prevalence of obesity. This article examines whether altering the cost of unhealthy, energy-dense foods, compared with healthy, less-dense foods through the use of fiscal pricing (tax or subsidy) policy instruments would, in fact, change food consumption patterns and overall diet enough to significantly reduce individuals' weight outcomes.

METHODS

This article examined empirical evidence regarding the food and restaurant price sensitivity of weight outcomes based on a literature search to identify peer-reviewed English-language articles published between 1990 and 2008. Studies were identified from the Medline, PubMed, Econlit, and PAIS databases. The fifteen search combinations used the terms obesity, body mass index, and BMI each in combination with the terms price, prices, tax, taxation, and subsidy.

FINDINGS

The studies reviewed showed that when statistically significant associations were found between food and restaurant prices (taxes) and weight outcomes, the effects were generally small in magnitude, although in some cases they were larger for low-socioeconomic status (SES) populations and for those at risk for overweight or obesity.

CONCLUSIONS

The limited existing evidence suggests that small taxes or subsidies are not likely to produce significant changes in BMI or obesity prevalence but that nontrivial pricing interventions may have some measurable effects on Americans' weight outcomes, particularly for children and adolescents, low-SES populations, and those most at risk for overweight. Additional research is needed to be able to draw strong policy conclusions regarding the effectiveness of fiscal-pricing interventions aimed at reducing obesity.

Food prices, access to food outlets and child weight

This study examines the importance of food prices and restaurant and food store outlet availability for child body mass index (BMI). We use the 1998, 2000 and 2002 waves of the child-mother merged files from the 1979 cohort of the National Longitudinal Survey of Youth combined with fruit and vegetable and fast food price data obtained from the American Chamber of Commerce Researchers Association and outlet density data on fast food and full-service restaurants and supermarkets, grocery stores and convenience stores obtained from Dun & Bradstreet. Using a random effects estimation model, we found that a 10% increase in the price of fruits and vegetables was associated with a 0.7% increase in child BMI. Fast food prices were not found to be statistically significant in the full sample but were weakly negatively associated with BMI among adolescents with an estimated price elasticity of -0.12. The price estimates were robust to whether we controlled for outlet availability based on a per capita or per land area basis; however, the association between food outlets and child BMI differed depending on the definition. The associations of fruit and vegetable and fast food prices with BMI were significantly stronger both economically and statistically among low- versus high-socioeconomic status children. The estimated fruit and vegetable and fast food price elasticities were 0.14 and -0.26, respectively, among low-income children and 0.09 and -0.13, respectively, among children with less educated mothers.