Inconsistent access to food may contribute to obesity

Parke Wilde © VITO ALUIA

Parke Wilde, a food economist at the Friedman School of Nutrition Science and Policy, and co-author Jerusha N. Peterman, a student in the Food Policy and Applied Nutrition Program at the Friedman School, analyzed data from the National Health and Nutrition Examination Survey (NHANES), an ongoing study of more than 10,000 Americans.

“To my knowledge, this is the first study to focus on the association between adults’ food security status and change in weight over time using national-level data,” Wilde said.

Household food insecurity is defined as “the lack of access to enough food for household members at all times in socially acceptable ways.” Wilde said the research may have implications for federal food assistance and nutrition programs designed to improve nutrition and household food security for low-income Americans.

The researchers analyzed NHANES data from 1999 to 2002, accounting for factors that might influence both weight and food security status, such as income, race/ethnicity, education level and health status. Survey respondents were classified into four levels of household food security, ranging from fully food secure to food insecure with hunger. With the exception of those living in households with the most severe level of food insecurity, women in food-insecure households were 50 percent more likely to be obese and to gain at least 10 pounds in one year, compared with women in fully food-secure households. These relationships were similar for men, but not as pronounced as they were for women.

The “gradual weight gain may occur from inconsistent access to food, leading to periods of under-consumption followed by compensatory over-consumption,” Wilde said. “Alternatively,” he added, “when money is less available, people may consume inexpensive, high-calorie foods.”

Changes to some food assistance programs might reduce the problem, Wilde said. “Food stamps are available in monthly cycles. This may lead to uneven purchasing and consumption. Perhaps the federal Food Stamp Program could be modified to provide benefits more frequently to even the distribution.”

Wilde also suggested ways that nutrition education programs can be used to help discourage consumption patterns that promote obesity. For example, he said, the USDA’s Expanded Food and Nutrition Education Program (EFNEP) might be able to teach low-income families strategies to manage their resources in such a way that consumption is more stable over time.

“Our results for weight change bolster the circumstantial evidence that intermediate levels of household food insecurity contribute to weight gain and risk of obesity,” Wilde said. “However, firm causal claims cannot be made using our research,” he cautioned. “If we can identify economic factors that increase the risk for obesity among low-income Americans, we can work to modify some of these risk factors.”