Predicting consumption of the USDA protein sub-recommendations among adults: a reasoned action approach

Background: There is reportedly an under-consumption of protein foods from sub-recommendations within the Dietary Guidelines for Americans (meat, poultry, and eggs, seafood, and nuts, seeds and soy-products). The purpose of this study was to operationalise the Reasoned Action Approach (RAA) to better understand the theory-based factors associated with the consumption of all three protein sub-recommendations. Methods: A national sample of adults in the United States of America (n=372) were recruited. Protein was evaluated using a modified version of a previously validated survey. RAA variables (intentions, instrumental and experiential attitudes, injunctive and descriptive norms, autonomy, and capacity) were measured for each protein sub-recommendation. Linear regression analyses were used to evaluate determinants of intentions and consumption of protein from each sub-recommendation. Results: Adults predispositions were significantly higher (P’s<0.05) for consuming meats, poultry and eggs [intentions (1.43), instrumental (1.51) and experiential (1.49) attitudes, injunctive (1.23) and descriptive (1.14) norms, autonomy (2.16), and capacity (2.07)], compared to the other groups [seafood (intentions (-0.24), instrumental (0.37) and experiential (0.63) attitudes, injunctive (0.17) and descriptive (-0.46) norms, autonomy (1.73), and capacity (0.94)); nuts, seeds, and soy products (intentions (0.57), instrumental (0.76) and experiential (0.85) attitudes, injunctive (0.47) and descriptive (-0.01) norms, autonomy (1.91), and capacity (1.62))]. A significant amount of the variance was explained for each protein sub-recommendation using the RAA variables[meats, poultry and eggs (intentions adjusted R2=0.596/ behaviour adjusted R2=0.166); seafood (intentions adjusted R2=0.691/ behaviour adjusted R2=0.363); nuts, seeds and soy-products (intentions adjusted R2=0.582/ behaviour adjusted R2=0.390)]; however not all variables were significant. Conclusions: The RAA appears to be a robust model for explaining why adults under consume protein foods from the USDA sub-recommendations. Future public health education interventions should give particular attention to seafood’s and nuts, seeds, and soy products affordability while maintaining palatability.