The Association between Food-Away-From-Home Frequency and a Higher BMI Varies by Food Security Status in US Adults

Background: For decades, Americans have increasingly relied on food away from home (FAFH) despite its association with negative health outcomes. Little is known about FAFH frequency and expenditures of adults with lower food security (FS) and their association with health outcomes, such as BMI. Objectives: We evaluated patterns of adults' FAFH purchases by FS status and other demographic characteristics, and examined the association between FAFH frequency and BMI in adults of varying levels of FS. Methods: This cross-sectional study used data from the Consumer Behavior Survey, Food Security Survey, and anthropometric measurements to assess FAFH frequency and expenditures, FS, and calculated BMI of adults (≥18 y) who participated in the NHANES 2007-2014 (n = 20,733). We used multinomial logistic regression to examine the association between FAFH frequency quartiles (quartile 1: 0 n/wk; quartile 2: 1-2 n/wk; quartile 3: 3-4 n/wk; quartile 4: ≥5 n/wk) and BMI by FS category. Results: Although FAFH frequency was similar across FS levels, adults with high FS spent more dollars (${\$}$213.60) and a greater proportion (29.4%) of their food budget on FAFH compared with adults with marginal, low, and very low FS (${\$}$133.00, ${\$}$116.20, ${\$}$103.30 and 21.4%, 19.7%, 20.0%, respectively). Obesity prevalence was highest in adults with low FS (42.9%) and very low FS (41.5%), and lowest in adults with high FS (33.7%). FAFH frequency and BMI were positively associated in adults with high (P < 0.001), marginal (P = 0.025), and low (P = 0.024) FS, but not in adults with very low FS (P = 0.589). Conclusions: FAFH is frequent in adults regardless of FS status. The positive association between FAFH and BMI is the strongest in adults with high FS, the group with the lowest prevalence of obesity. Conversely, BMI was not associated with FAFH in adults with very low FS, despite their higher prevalence of obesity.