ARS | Publication request: Estimating dietary costs of low-income women in California: A comparison of two approaches

Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 10, 2012
Publication Date: N/A

Interpretive Summary: To better understand diet costs at the individual level new, stream-lined approaches are needed. By linking food costs of individual food items to a food frequency questionnaire, an estimate of typical daily diet cost can be estimated. This approach was compared to a more time-intensive method of obtaining multiple 24-hour dietary recalls and associated receipts from grocery stores. The diet costs in $ spent per day or $ spent per calorie intake did not differ between the less intensive and more intensive method. Although the agreement between methods was weaker than expected, the less time-intensive method shows promise but needs further refinement to improve accuracy.

Technical Abstract: Objective: Compare two approaches for estimating individual daily diet costs in a population of low-income women in California. Design: Cost estimates based on time-intensive Method 1 (three 24-h recalls and associated food prices on receipts) were compared with estimates using a lesser intensive Method 2 (a food frequency questionnaire and store prices). Subjects: SNAP-Ed and EFNEP participants (n=121) were recruited. Main outcome measures: mean daily diet costs, both unadjusted and adjusted for energy, were compared using Pearson correlation coefficients and the Bland-Altman 95% limits of agreement between methods. Results: Energy and nutrient intakes derived by the two methods were comparable; where differences occurred, the FFQ (Method 2) provided higher nutrient values than did the 24-h recalls (Method 1). Crude daily diet cost was $6.32 by the 24-h recall method and $5.93 by the FFQ method (P = 0.221). Energy adjusted diet cost was $6.65 by the 24-h recall method and $5.98 by the FFQ method (P <0.001). Conclusions Although the agreement between methods was weaker than expected, both approaches may be useful. Additional research is needed to further refine a large national survey approach to estimate daily dietary costs using a minimal time-intensive method.