Cutting the Fat
Exercise, Physical Activity, and Exertion over the Business Cycle
Gregory Colman & Dhaval Dave
NBER Working Paper, September 2011
Abstract:
As economic recessions reduce employment and wages, associated shifts in time and income constraints would be expected to also impact individuals' health behaviors. Prior work has focused exclusively on recreational exercise, which typically represents only about 4% of total daily physical exertion. The general presumption in these studies is that, because exercise improves health, if unemployment increases exercise it must also improve health. Yet a person may be laid off from a physically demanding job, exercise more, and still be less physically active than when employed. Thus the relevant question is whether unemployment leads persons to become more physically active. We study this question with the American Time Use Survey (2003-2010), exploring the impact of the business cycle (and specifically the Great Recession) on individuals' exercise, other uses of time, and physical activity during the day. We also utilize more precise measures of exercise (and all other physical activities), which reflect information on the duration as well as intensity of each component activity, than has been employed in past studies. Using within-state variation in employment and unemployment, we find that recreational exercise tends to increase as employment decreases. In addition, we also find that individuals substitute into television watching, sleeping, childcare, and housework. However, this increase in exercise as well as other activities does not compensate for the decrease in work-related exertion due to job-loss. Thus total physical exertion, which prior studies have not analyzed, declines. These behavioral effects are strongest among low-educated males, which is validating given that the Great Recession led to some of the largest layoffs within the manufacturing, mining, and construction sectors. Due to the concentration of low-educated workers in boom-and-bust industries, the drop in total physical activity during recessions is especially problematic for vulnerable populations and may play a role in exacerbating the SES-health gradient during recessions. We also find some evidence of intra-household spillover effects, wherein individuals respond to shifts in spousal employment conditional on their own labor supply.
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Pound Wise and Penny Foolish? Weight Loss and The Dynamics of Health Care Spending
Thomas Koch
Forum for Health Economics & Policy, 2011
Abstract:
Current estimates of obesity costs ignore the impact of future weight loss and gain, and may either over or underestimate economic consequences of weight loss. In light of this, I construct static and dynamic measures of medical costs associated with body mass index (BMI), to be balanced against the cost of one-time interventions. This study finds that ignoring the implications of weight loss and gain over time overstates the medical-cost savings of such interventions by an order of magnitude. When the relationship between spending and age is allowed to vary, weight-loss attempts appear to be cost-effective starting and ending with middle age. Some interventions recently proven to decrease weight may also be cost-effective.
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Contribution of Obesity to International Differences in Life Expectancy
Samuel Preston & Andrew Stokes
American Journal of Public Health, forthcoming
Objectives: The United States has the highest prevalence of obesity and one of the lowest life expectancies among high-income countries. We investigated the relationship between these 2 phenomena.
Methods: We estimated the fraction of deaths attributable to obesity by country, age, and sex and reestimated life tables after removing these deaths. To allow for a possible secular decline in obesity risks, we employed alternative risks from a more recent period.
Results: In our baseline analysis, obesity reduced US life expectancy at age 50 years in 2006 by 1.54 years (95% confidence interval [CI]=1.37, 1.93) for women and by 1.85 years (95% CI=1.62, 2.10) for men. Removing the effects of obesity reduced the US shortfall by 42% (95% CI=36, 48) for women and 67% (95% CI=57, 76) for men, relative to countries with higher life expectancies. Using more recently recorded risk data, we estimated that differences in obesity still accounted for a fifth to a third of the shortfall.
Conclusions: The high prevalence of obesity in the United States contributes substantially to its poor international ranking in longevity.
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Biing-Hwan Lin et al.
Economics & Human Biology, forthcoming
Abstract:
Taxing unhealthy foods has been proposed as a means to improve diet and health by reducing calorie intake and raising funds to combat obesity, particularly sugar-sweetened beverages (SSBs). A growing number of studies have examined the effects of such food taxes, but few have estimated the weight-loss effects. Typically, a static model of 3,500 Calories for one pound of body weight is used, and the main objective of the study is to demonstrate its bias. To accomplish the objective, we estimate income-segmented beverage demand systems to examine the potential effects of a SSB tax. Elasticity estimates and a hypothetical 20-percent effective tax rate (or about 0.5 cent per ounce) are applied to beverage intake data from a nationally representative survey, and we find an average daily reduction of 34 to 47 Calories among adults and 40 to 51 Calories among children. The tax-induced energy reductions are translated into weight loss using both static and dynamic calorie-to-weight models. Results demonstrate that the static model significantly overestimates the weight loss from reduced energy intake by 63 percent in year one, 346 percent in year five, and 764 percent in year 10, which leads to unrealistic expectations for obesity intervention strategies. The tax is estimated to generate $5.8 billion a year in revenue and is found to be regressive, although it represents about one percent of household food and beverage spending.
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The Socio-Economic Causes of Obesity
Charles Baum & Shin-Yi Chou
NBER Working Paper, September 2011
Abstract:
An increasing number of Americans are obese, with a body mass index of 30 or more. In fact, the latest estimates indicate that about 30% of Americans are currently obese, which is roughly a 100% increase from 25 years ago. It is well accepted that weight gain is caused by caloric imbalance, where more calories are consumed than expended. Nevertheless, it is not clear why the prevalence of obesity has increased so dramatically over the last 30 years. We simultaneously estimate the effects of the various socio-economic factors on weight status, considering in our analysis many of the socio-economic factors that have been identified by other researchers as important influences on caloric imbalance: employment, physical activity at work, food prices, the prevalence of restaurants, cigarette smoking, cigarette prices and taxes, food stamp receipt, and urbanization. We use 1979- and 1997-cohort National Longitudinal Survey of Youth (NLSY) data, which allows us to compare the prevalence of obesity between cohorts surveyed roughly 25 years apart. Using the traditional Blinder-Oaxaca decomposition technique, we find that cigarette smoking has the largest effect: the decline in cigarette smoking explains about 2% of the increase in the weight measures. The other significant factors explain less.
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P.T. Katzmarzyk & S.A. Lear
Obesity Reviews, forthcoming
Abstract:
The purpose of this review was to determine the effectiveness of physical activity in improving chronic disease risk factors in obese individuals. A systematic review was conducted to identify randomized physical activity intervention studies reporting changes in risk factors among obese individuals published prior to March 2010. Studies included in the review were randomized trials of at least 10 weeks in duration, with a sample mean body mass index ?30 kg/m2 at baseline, and reporting a relevant risk factor (blood pressure, blood lipids, glucose/insulin or C-reactive protein). Forty-four studies met the inclusion criteria for this review. Overall, physical activity had no more than a modest effect on chronic disease risk factors in obese individuals. There was great heterogeneity in responses of risk factors across studies. In many studies it was difficult to determine the effect of physical activity, independent of changes in body mass consequent to the intervention. Obese individuals should be encouraged to undertake physical activity following general recommendations for weight loss and health. The degree to which physical activity is effective at lowering risk factor levels among high-risk obese individuals is not known.
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Taxing Sweets: Sweetener Input Tax or Final Consumption Tax?
Zhen Miao, John Beghin & Helen Jensen
Contemporary Economic Policy, forthcoming
Abstract:
Policymakers are considering various policies to reduce obesity and its associated costs, including consumption taxes on high-calorie foods and specifically sweetened foods. We investigate two tax policies to reduce added sweetener consumption: a consumption tax on sweetened goods and a sweetener input tax. Both tax instruments can reach the same policy target of reducing added sweetener consumption and are found to be regressive. The tax on sweetener inputs targets sweeteners directly and leads to a loss in consumer surplus that is only one-fifth of that caused by the final consumption tax. Previous analyses have overlooked this important point.
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Racial, Ethnic and Gender Differences in Physical Activity
Henry Saffer, Dhaval Dave & Michael Grossman
NBER Working Paper, September 2011
Abstract:
This study examines racial, ethnic and gender differentials in physical activity. Individuals engage in physical activity during leisure-time and also during in many other activities such as walking to work, home maintenance, shopping and child care. Physical activity also occurs on the job is this is referred to as work physical activity. Prior studies have shown that non-work physical activity has a positive impact on health while work physical activity has a negative impact on health. Many prior studies have relied primarily on leisure-time physical activity, which typically constitutes only about 10% of non-work physical activity and does not capture specific information on the intensity or duration of the activity. This study addresses these limitations by constructing measures of physical activity from the American Time Use Surveys, which are all-inclusive and capture the duration of each activity combined with its intensity based on the Metabolic Equivalent of Task (MET). Non-work physical activity tends to be significantly lower for Blacks, Hispanics, other racial groups than for Whites and lower for males than for females. These adjusted differentials are consistent with racial, ethnic and gender differentials in health. About 25-46% of the differentials in non-work physical activity can be attributed to differences in education, socio-economic status, proxies for time constraints, and locational attributes.
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Associations between Household Income, Height, and BMI in Contemporary US Schoolchildren
Jason Murasko
Economics & Human Biology, forthcoming
Abstract:
This paper evaluates the association between income and physical development in a nationally-representative sample of contemporary US schoolchildren followed from kindergarten to eighth grade (average ages of 6 to 14). A generalized linear mixed modeling framework is used to evaluate height and body mass index (BMI) as both levels and annualized growth in a pooled sample. Contemporary US schoolchildren show income variation in height that is significant but modest at around .1 cm (in kindergarten) to .4 cm (eighth grade) increases per doubling of income. An exception is found for Hispanic children who show faster height velocity associated with higher income through childhood yielding a 1.0 cm increase per doubling of income by the eighth grade. All groups except black males show a negative relationship between income and BMI that becomes stronger with age with an average .8 kg/m2 lower BMI per doubling of income by the eighth grade. These results are robust to the inclusion of baseline anthropometric controls. The analysis suggests that higher-income US schoolchildren enter mid-adolescence as taller but with lower proportional body mass relative to their lower-income counterparts.
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Are Poor Neighborhoods "Retail Deserts"?
Jenny Schuetz, Jed Kolko & Rachel Meltzer
Regional Science and Urban Economics, forthcoming
Abstract:
Poor urban neighborhoods are often referred to as "food deserts", lacking in grocery stores and healthy food vendors. However, most empirical studies of food deserts have been small scale, focusing on limited geographies and a narrow range of products. Standard retail location models, which often assume that consumers have identical preferences and are uniformly distributed through space, provide little insight into the relationship between local income and retail patterns. In this paper, we examine the relationship between neighborhood income and retail density for several types of goods and services in 58 large U.S metropolitan areas. We combine detailed data from the National Establishment Time- Series database on retail establishments and employment, by industry category and firm type, with Census data on ZCTA income, poverty and demographics. Results indicate that retail patterns do vary by neighborhood income, along many dimensions. High poverty neighborhoods have lower employment density for retail overall, supermarkets, drugstores, food service and laundry facilities, driven largely by reduced employment in chain establishments. Average establishment size increases with median income for all retail types. Neither income levels nor poverty rates consistently predict retail employment growth, but neighborhoods that experience income upgrading do see larger gains in retail employment.
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Dropping the weight stigma: Nostalgia improves attitudes toward persons who are overweight
Rhiannon Turner, Tim Wildschut & Constantine Sedikides
Journal of Experimental Social Psychology, forthcoming
Abstract:
Weight stigma, a negative attitude toward persons who are overweight, can lead to emotional detriment (increased vulnerability to depression and anxiety, decreased self-esteem) and discriminatory practices (denial of employment, lower wages, refusal of job promotion or college admission, healthcare deprivation), which have increased dramatically in the United States over the past decade. We report two experiments that implicate nostalgia as a resource or strategy for weight stigma reduction. We hypothesized and found that nostalgia about an encounter with a person who is overweight improves attitudes toward the group "overweight." Undergraduates who recalled a nostalgic (vs. ordinary) interaction with an overweight person subsequently showed more positive outgroup attitudes. The effect of nostalgia on outgroup attitudes was mediated by greater inclusion of the outgroup in the self and increased outgroup trust (Experiments 1 and 2), as well as reduced intergroup anxiety and greater perceptions of a common ingroup identity (Experiment 2). The findings have interventional potential.
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The neurocognitive connection between physical activity and eating behavior
R.J. Joseph et al.
Obesity Reviews, October 2011, Pages 800-812
Abstract:
As obesity rates increase worldwide, healthcare providers require methods to instill the lifestyle behaviours necessary for sustainable weight loss. Designing effective weight-loss interventions requires an understanding of how these behaviours are elicited, how they relate to each other and whether they are supported by common neurocognitive mechanisms. This may provide valuable insights to optimize existing interventions and develop novel approaches to weight control. Researchers have begun to investigate the neurocognitive underpinnings of eating behaviour and the impact of physical activity on cognition and the brain. This review attempts to bring these somewhat disparate, yet interrelated lines of literature together in order to examine a hypothesis that eating behaviour and physical activity share a common neurocognitive link. The link pertains to executive functions, which rely on brain circuits located in the prefrontal cortex. These advanced cognitive processes are of limited capacity and undergo relentless strain in the current obesogenic environment. The increased demand on these neurocognitive resources as well as their overuse and/or impairment may facilitate impulses to over-eat, contributing to weight gain and obesity. This impulsive eating drive may be counteracted by physical activity due to its enhancement of neurocognitive resources for executive functions and goal-oriented behaviour. By enhancing the resources that facilitate 'top-down' inhibitory control, increased physical activity may help compensate and suppress the hedonic drive to over-eat. Understanding how physical activity and eating behaviours interact on a neurocognitive level may help to maintain a healthy lifestyle in an obesogenic environment.
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Parenthood and trajectories of change in body weight over the life course
Debra Umberson et al.
Social Science & Medicine, forthcoming
Abstract:
Scholars call for greater attention to social contexts that promote and deter risk factors for health. Parenthood transforms social contexts in a myriad of ways that may influence long-term patterns of weight gain. Life course features of parenthood such as age at first birth, parity, and living with a minor child may further influence weight gain. Moreover, the social and biological features of parenthood vary in systematic ways for women and men, raising questions about how social contexts might differentially affect weight patterns by gender. We consider how parenthood influences trajectories of change in body weight over a fifteen year period (from 1986 to 2001) with growth curve analysis of data from the Americans' Changing Lives Survey, conducted with adults aged 24 and older in the contiguous United States (N = 3617). Findings suggest that parents gain weight more rapidly than the childless throughout the study period and that this weight gain occurs for both men and women. Men and women who have their first child earlier or later than about age 27 have accelerated weight gain, living with a minor child is associated with heavier weight for men than women, and parity is associated with greater weight gain for women than men. We conclude that parenthood contributes to a long term, cumulative process of weight gain for American women and men but life course factors that accelerate this process may differ by gender.