Most U.S. households have consistent, dependable access to enough food for active, healthy living—they are food secure. But a growing number of American households experience food insecurity at times during the year, meaning that their access to adequate food is limited by a lack of money and other resources. [1
] In 1995, when the U.S. Department of Agriculture (USDA) published its initial report on U.S. household food security, approximately 11.9% of households experienced food insecurity. [2
] Current estimates have increased to 14.6%, as of 2008. In other words, after thirteen years of monitoring food security, hardship has worsened from one in ten to one in seven households affected. These trends have led to increased research about the characteristics and consequences of food insecurity.
Several terms exist to identify food insecurity, including food hardship, food insufficiency, and hunger. [3
] Numerous definitions have been proposed to classify these terms, but the most commonly referenced resource for definition and measurement is the USDA. It defines household food security as “access by all members at all times to enough food for an active, healthy life.” [1
] At a minimum, nutritionally adequate and safe foods are readily available and can be acquired in socially acceptable ways (i.e. without stealing, accessing emergency food supplies, or relying on other coping strategies). Alternatively, food insecurity implies a “limited or uncertain availability of nutritionally adequate and safe foods or limited or uncertain ability to acquire acceptable foods in socially acceptable ways.” As of 2006, four categories classify the continuum of food security: high, marginal, low, and very low, based on responses to the 18-item USDA Core Food Security Module (CFSM). The latter two categories were previously named food insecurity without hunger and food insecurity with hunger, respectively. The revision was made to reflect that hunger was a related, but distinctive, phenomenon that could not be defined or measured appropriately in the context of food insecurity.
Due to the enhanced use of the CFSM in national surveys, both the USDA and other leading researchers in the field have identified key populations most likely to experience this food insecurity. Numerous studies have named low-income, single-female headed households, minority race, lower education levels, and more children or other household members as characteristics associated with this form of hardship. [3
] Other research suggests limited availability and accessibility to healthy food outlets as another contributor. [7
] These factors often provoke changes in dietary intake and food behaviors. For example, members of food insecure households tend to consume foods that are high in energy density but are nutritionally poor. In addition, in circumstances where food is limited, individuals report overeating or eating foods they dislike to compensate for periods of lack. These very behaviors underlie diet-related disorders, including obesity and diabetes, and other chronic and mental health issues. [9
] Consequently, the costs of nutritional deprivation to individuals, communities, and society are enormous. A 2007 study led by Brown estimated annual costs associated with hunger (using the revised USDA food insecurity categories to define hunger) in the United States to exceed $90 billion. [12
] The authors concluded that increased investments in federal food assistance programs could greatly reduce this burden.
The first step in decreasing the burden of food insecurity is to gain a better understanding of its effects on health. To this end, an increasing number of studies have aimed to summarize the impacts of food insecurity on health outcomes in children and adults. Specifically, the food insecurity-obesity paradox has been examined in a literature review by Dinour. [13
] In her review, she summarized fourteen studies published from 1999 to 2006 which lend consistent support to positive insecurity and obesity links among women, mixed results among youth, and little or no evidence among men. Specifically, several studies affirmed highest levels of overweight/obesity among persons reporting the most severe categories of insecurity. Studies examining race differences found significant relationships more often among non-Hispanic white and Hispanic groups than among non-Hispanic blacks. Moreover, the authors explored the potential impact of food stamp program participation on the food insecurity-obesity relationship. The findings from Dinour’s review provided a new basis for future evaluations.
The number of publications exploring the food insecurity-obesity paradox has increased significantly over the past few years. New research is examining additional factors that may more accurately explain this relationship. Moreover, with the availability of validated measures of food security, overweight, and obesity, comparability across studies is enhanced (). For these reasons, an updated review of the literature was warranted. The aim of this review is to update the literature, comparing with the previous review to clarify associations of food insecurity and overweight/obesity across adult and youth populations. Finally, in light of new evidence, suggestions for future studies will be proposed.
Definitions for food security and weight status measures used in studies