Project:
The Food Insecurity-Obesity Paradox in Women

Year: 2003

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

Investigator: Olson, Christine M., and Myla S. Strawderman

Institution: Cornell University

Project Contact:
Christine M. Olson, Professor
Dept. of Nutritional Science
376 Martha Van
Cornell University
Ithaca, NY 14850
Phone: 607-255-2634
Cmo3@cornell.edu

This study examined the relationship between food insecurity and obesity and the mechanisms through which food insecurity might lead to obesity in a sample of 436 healthy adult women from rural upstate New York.

The study had a prospective cohort design and women were followed from early pregnancy until 2 years postpartum. Data were collected through self-administered behavioral questionnaires, food frequencies, and a medical record audit. Height and weight measurements at all time points were measured by healthcare providers following standardized study protocols.

Study results indicated that food insecurity at the beginning of pregnancy was positively associated with major weight retention at 2 years postpartum, but only in initially obese women (at a marginal significance level of 0.007). Initial obesity was also associated with increased risk of becoming food insecure (at a marginal significance level of less than 0.05). Measures of quantity of food intake, dietary quality, eating patterns, and physical activity were examined as potential mediators. Consuming fewer than three fruits and vegetables per day and a more binge-like pattern of eating were associated with initial food insecurity and major weight retention at 2 years postpartum (at a marginal significance level of less than 0.05). When these variables were added to the regression model they did not reduce the coefficient for food insecurity, a final criterion for being a mediating variable.

Obesity during early pregnancy was associated with increased risk of becoming food insecure. The cross-lagged panel analysis indicated that this causal direction was statistically significant when controlling for initial food insecurity and weight status, while the other was not. This result provides support for what can be described as ""reverse causality."" Thus, the previous findings from cross-sectional studies of an association between food insecurity and obesity may be due to the fact that obese women are at increased risk of becoming food insecure over time.

Overall, no variables emerged as obvious mediators of the relationship between initial food insecurity and major weight gain or change in food security status (particularly becoming food insecure) and major weight gain. The small sample sizes and the large variation of some of the variables may have contributed to the lack of significant findings related to the mediators.

There are several other potential explanations for the study findings. One is the possible timing of the measurement of the mediating variables. They were measured over a year after the initial food insecurity measurement was taken and this time period included a pregnancy. Additional data indicate that all women's diets were similar during pregnancy regardless of their initial food insecurity status. Seventy percent of food-insecure women participated in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) during pregnancy. The additional food from this program may have blunted any impact of food insecurity on eating during pregnancy and this effect may have carried over into the postpartum period, although the data clearly indicate that the initially food-insecure women ate differently at 1 year postpartum than did food-secure women. The dietary variables were measured a year before the weight measurement was taken and it may be that change in diet related to weight change took place closer to 2 years postpartum.

Women who were initially food insecure and were also obese formed a distinct subgroup especially vulnerable to weight gain. This is a group that may merit targeting for special intervention in food assistance programs. Development and implementation of approaches to secondary prevention, in the context of WIC, which is generally oriented toward primary prevention, would require careful consideration of the length of postpartum participation allowed, the composition of the WIC food package, and the focus and content of nutrition education.