Meal Protein Quality Score (MPQS) assessment of protein adequacy across meals in Dutch elite and sub-elite athletes

Adequate daily protein intake does not necessarily ensure sufficient per-meal level of essential amino acids, particularly when meals rely on plant protein sources. We evaluated meal-level protein quality in elite and sub-elite Dutch athletes using the Meal Protein Quality Score (MPQS). This secondary analysis used non-consecutive 24-h dietary recalls from the Dutch Sport Nutrition and Supplement Study (2012–2015). MPQS was calculated for breakfast, lunch and dinner, assuming a per-meal protein target of 0.4 g·kg⁻¹ body mass. Multivariable regression and network analyses were performed to identify dietary determinants of meal protein quality. Data from 503 athletes (299 men, 204 women) were analyzed. Median MPQS was lowest at breakfast (71 [IQR 43–109]) compared with lunch (93 [48–146]) and dinner (147 [85–219]). Accordingly, 71% of breakfasts and 54% of lunches had an MPQS < 100, meaning that at least one essential amino acid did not meet the meal requirement, while more than one-quarter of dinners also remained below this threshold. When considering meals containing meat and/or fish, MPQS values were higher across meals (breakfast: 94 [60–136]; lunch: 117 [68–169]; dinner: 174 [120–238]). Vegetarian meals showed lower MPQS values across meals, and fully plant-based meals rarely met the adequacy threshold of MPQS ≥ 100 (breakfast: 25 [15–40]; lunch: 21 [6–34]; dinner: 21 [10–31]). Network analysis identified energy intake as the strongest positive correlate of MPQS, whereas breakfast meals and a higher proportion of plant protein were negatively associated. In multivariable analyses, meat and poultry, cold meat cuts, milk and milk products, savoury snacks, and cereals and cereal products were positively associated with MPQS (all p < 0.001). In fully plant-based meals, nuts and seeds, savoury spreads, and meat and dairy substitutes were the strongest positive contributors (all p < 0.001). Despite generally adequate daily protein intake, meal-level protein quality is frequently insufficient in elite and sub-elite Dutch athletes. Optimization and complementary plant-protein combinations may help athletes achieve essential amino acid adequacy at each main meal. Future intervention studies are needed to determine whether improving meal-level protein quality translates into enhanced muscle protein synthesis, recovery, and athletic performance.