1. Introduction
SECONDARY
Background: The Dietary Guidelines for Americans (DGA) recommends consuming a variety of “Protein Foods” based on “ounce-equivalent” (oz-eq) portions. No study has assessed the same oz-eq portions of animal- vs. plant-based protein foods on essential amino acid (EAA) bioavailability for protein anabolism in young and older adults. Objectives: We assessed the effects of consuming two oz-eq portions of pork, eggs, black beans, and almonds on postprandial EAA bioavailability in young and older adults. Methods: We conducted two investigator-blinded, randomized crossover trials in young (The 2020–2025 Dietary Guidelines for Americans (DGA) recommend that “Protein Foods” should be consumed as part of a healthy dietary pattern [Research by Park et al. [Therefore, we conducted two sequentially randomized, investigator-blinded, crossover acute feeding trials with the same study design: the first in a cohort of young adults and the second in a cohort of older adults. The primary objective of this project was to assess the effect of consuming two oz-eq portions of animal-based (unprocessed lean pork or whole eggs) vs. plant-based (black beans or sliced almonds) protein foods as part of a mixed whole foods meal on plasma EAA bioavailability for protein anabolism. We hypothesized that consuming a meal with two oz-eq portions of animal-based protein foods would result in greater postprandial EAA bioavailability compared to plant-based protein foods (primary) and would not elicit differential EAA bioavailability responses between young and older adults (secondary). This research will serve as an important resource for future DGAs to reevaluate the appropriateness of equating different protein sources comprising the protein foods group on an oz-eq basis for young and older adults. 