Differences in Protein Quantity and Quality Across a Spectrum of Plant-Based Meals: Analysis of a Large National Dietary Survey.

Abstract

Current recommendations encourage consuming sufficient intake of high-quality protein, with ≥60% derived from plant-based sources, to support both nutritional requirements and sustainability goals. This observational study assessed protein intake, quality, and sources in predominantly plant-based meals and diets using a national survey, offering insights to support a more sustainable and nutritionally adequate dietary transition. In the Dutch National Food Consumption Survey (2019-2021), protein intake was assessed using 24-h recalls in adults aged 18 to 79 y. Total, plant-based, and animal-based protein intake were analyzed per meal and per day. Protein quality per meal was evaluated using the Meal Protein Quality Score (MPQS). The association between protein quantity and the proportion of plant-based protein was evaluated based on how often meals reached adequate protein quality (MPQS >100). Furthermore, protein sources across food groups in diets with ≥60% and <60% plant-based protein were compared. Among 1747 adults [57 (44-68) y, 50% male], the median protein intake was 0.93 (0.75-1.13) g/kg/d. Only 8% ( n = 147) had a diet comprising ≥60% plant-based protein, with a median intake of 0.83 (0.63-1.05) g/kg/d. As the proportion of plant-based protein increased, both protein quantity and quality decreased. When protein quality was low, lysine was the most common limiting amino acid. Only 3% of all meals achieved ≥20 g protein, ≥60% plant-based protein, and optimal protein quality, with dairy as key protein source at breakfast and lunch, meat alternatives at dinner, and grains at all meals. This study shows that only a small proportion of Dutch adults met both protein-related recommendations and sustainability goals, due to lower protein quantity and quality in more plant-based diets. This study emphasizes the need for professional guidance, especially in individuals with higher protein requirements, to facilitate a successful transition to a more plant-based diet.