Food insecurity and obesity among US young adults: the moderating role of biological sex and the mediating role of diet healthfulness.

OBJECTIVE:To examine the association between food insecurity (FI) and obesity, measured by BMI and waist circumference (WC), among young adults and test the moderating role of biological sex and the mediating role of diet healthfulness (DH). DESIGN:Cross-sectional. SETTING:National Health and Nutrition Examination Survey 2011-2016. PARTICIPANTS:The sample included 4667 young adults aged 18-35 years. RESULTS:Given the interaction terms between sex and FI, biological sex was a moderator between both FI and WC (P = 0·031) and FI and BMI (P = 0·007) among young adults. FI was associated with a 1·16 kg/m2 higher BMI (95 % CI 0·27, 2·05) and a 2·09 cm larger WC (95 % CI 0·05, 4·14) among young female adults, while FI was associated with a 0·26 kg/m2 higher BMI (95 % CI -0·65, 1·16) and a 0·78 cm larger WC (95 % CI -1·13, 2·89) among young male adults. DH mediated the relationships between both FI and BMI (indirect effect β = 0·14; 95 % CI 0·05, 0·23) and FI and WC (indirect effect β = 0·31; 95 % CI 0·10, 0·51) among females. Females with FI had poorer DH and thus had higher BMI and larger WC. CONCLUSIONS:Young female adults with FI were more likely to experience overall and abdominal obesity compared with their male counterparts. Results also suggest that females with FI had poorer DH and thus had increased risk of both abdominal and overall obesity.