Is There a Link Between Food Insecurity and Overweight Status in Children? Evidence from the Early Childhood Longitudinal Survey

Year: 2004

Research Center: Department of Nutrition at the University of California, Davis

Investigator: Rose, Donald, and Nick Bodor

Institution: Tulane University

Project Contact:
Diego Rose
Department of Community Health Sciences
Tulane University School of Public Health and Tropical Medicine
1440 Canal Street, Suite 2301
New Orleans, LA 70112
Phone: 504-988-5391


Recent literature indicates that close to two-thirds of the U.S. adult population is overweight or obese. Moreover, the prevalence of obesity has increased in the United States, particularly among children. This research identified literature linking obesity with increased risk of poor health outcomes, such as cardiovascular disease, diabetes, and cancer.

While there is little controversy about the proximal determinants of overweight status—imbalance between energy intake and expenditure—there is considerable complexity in the framework of distal factors that give rise to this imbalance. An emerging area of research exploring distal factors is concerned with the relationship between household food insecurity and obesity.

Several empirical studies cited in the report have explored the food insecurity weight status relationship. There is apparent agreement among studies of adult women: most studies show a positive association between food insecurity and the probability of being overweight. While a positive relationship may seem paradoxical, several explanations are possible. Food insecurity could lead to overweight status if individuals overcompensate for periods when food is scarce, resulting in greater overall intake. Weight cycling could also make the body more efficient in utilizing dietary energy, leading to weight gain over time. Finally, energy-dense foods are often less expensive, so that food-insecure households who cannot afford to eat balanced meals or who must rely on a few kinds of low-cost foods may have an overall greater energy intake.

No clear pattern has emerged regarding the food insecurity-overweight link in children. Some authors have suggested that the issue in children is unresolved because of limitations (including sample size) of previous datasets. Literature cited in the report has found that food insecurity or hunger is associated with negative academic outcomes and poor psychosocial functioning at school, adverse health outcomes, and poor mental health. The objective of this research is to test the hypothesis that household food insecurity is positively associated with overweight status in children.

The study analyzes data collected in the Department of Education’s Early Childhood Longitudinal Survey-Kindergarten Cohort (ECLS-K). The ECLS-K is a large nationally representative survey of children which began with the kindergarten class of 1998-99. The survey collected measures of children’s heights and weights twice per year in the kindergarten and first grade, the full 18-item USDA food insecurity module in the spring of 1999, and a rich set of variables on the home and school environments of these children. Algorithms from the Centers for Disease Control and Prevention (CDC) were used to assign Body Mass Index (BMI)-for-age percentiles to each child’s measurements. Children with a BMI greater than or equal to the 95th percentile of their sex-specific BMI-for-age chart were considered overweight. In addition to this indicator, the study calculated a dichotomous variable indicating “risk of overweight,” a CDC term for children with a BMI greater than or equal to the 85th percentile of their BMI-for-age chart.

Weight status is affected by a number of biological and socio-economic factors. To control for potentially confounding variables, the research developed multivariate logistic regression models in which the dependent variable was a dichotomous indicator of overweight status. Independent variables included a measure of household food insecurity and a full set of control variables, including: age, sex, and birth weight of the children; maternal educational attainment; income, region, and urbanization of the household; as well as family meal patterns and child activity patterns. All analyses used ECLS-K weighting variables, and accounted for the clustered nature of the sample by using jackknife replicate methods to estimate standard errors.

The primary study finding is that household food insecurity, when modeled with appropriate controls, is not associated with a higher prevalence of overweight among young school children. If anything, household food insecurity seems inversely associated with weight status. The finding is relatively robust, since similar results were demonstrated across a range of different models. The study applied dichotomous (food secure/insecure) and trichotomous (food secure/insecure without hunger/insecure with hunger) expressions of the household food security variable and also used dichotomous and trichotomous expressions for child food insecurity. Models using different expressions of the dependent variable were performed, using “risk of overweight” as an indicator in one model, and simply BMI in continuous form in another. A cross-section analysis based on data collected in the spring of the children's kindergarten year was run. It should be noted that parents reported on household status in the 12 months prior to the interview, so in effect a food-insecure condition would have preceded the children's weight status. The research further tested whether household food insecurity in the spring of 1999 was predictive of overweight status a year later and found that it was not. Additionally, the study tested whether household food insecurity in 1999 was predictive of a high weight gain over the next year and found an inverse association.

These findings may mean that food insecurity is less relevant for those whose main concern is childhood obesity than for those focused on academic and psychosocial outcomes or physical and mental health. In addition, study estimates indicated that while 10 percent of the sample overweight children came from food insecure households, 24 percent came from households in poverty. Thus, targeting overweight prevention might be more focused on a general population of the poor than on the food-insecure population. Moreover, social marketing techniques or environmental change strategies that affect large groups of people may cost less than strategies that must first identify food-insecure households.