Food Insecurity and Obesity in Low-Income Women: The Monthly Cycle of Food Abundance and Food Shortage.

摘要

Food insecurity has been associated with overweight/obesity in U.S. women. Several hypotheses have been proposed to address this paradoxical association, but none has yet been tested. This dissertation is designed to test the "monthly cycle of food abundance and food shortage" hypothesis, and to examine the effects of food stamp program (FSP) participation, disordered eating, and dietary intake patterns on the association. It is hypothesized that food insecure women would experience a monthly cycle with higher total energy intake (TEI) and household food stores at the beginning of the month, followed by a more limited TEI and food supply at the end.;The dissertation compared food insecure and overweight/obese (FIS/ovob) women with three other women groups: food secure and normal weight (FS/norm), food secure and overweight/obese (FS/ovob), and food insecure and normal weight (FIS/norm). The monthly variations in TEI and food stores were assessed in a sample of low-income women in Ohio, by comparing the energy intake from the first ten days with that of the last ten days of the month during three continuous months. For FIS/ovob women, significant decreases were found in the total number of food items (Month 1: 87.74 vs. 68.26, Month 2: 83.3 vs. 72.2, Month 3: 88.81 vs. 75.3, p<0.05) and in essential food groups including grains, vegetables, fruits, meat & beans, and milk; in TEI (2114.19 vs. 1843.06 kcal, p<0.05) and fat intake (804.1 vs. 649.93 kcal, p<0.05) in Month 1. Among food insecure women, food stamp recipients showed a higher BMI (38.24 vs. 30.94, p<0.01) and more severe decreases in three-month food items (61.58 vs. 8.22, p<0.01) than non-recipients. In addition, deeper food insecurity was marginally correlated with more severe Eating Concern in disordered eating (Pearson's correlation: 0.23, p=0.09). Using the National Health and Nutrition Examination Survey (NHANES) 1999--2008 data, a higher carbohydrates/energy ratio and a lower protein/energy ratio was found in FIS/ovob women compared to food secure women; no differences of TEI or fat/energy ratio were observed. Furthermore, FIS/ovob women showed higher prevalence of a 4.54 kg (10 lbs) 1-yr weight gain (28.81%) than other women groups. The results suggest the existence of the monthly cycle of food abundance and food shortage in FIS/ovob women, which may be caused by the interaction in food insecurity with FSP participation; carbohydrate intake may increase, and daily energy intake and fat intake may fluctuate in response to the monthly cycle and result in gradual weight gain over long periods of time. Policy changes may be necessary; nutrition education integrating with community-based intervention programs and efforts from private sectors like food providers are needed for FIS/ovob women to have a more even distribution of available food sources throughout the month, and a reduction of the potentially episodic overeating behaviors.