ABSTRACT
Background
Military personnel engaged in intense activities must consume enough quality protein in their diet to maintain protein balance and promote recovery. Plant-based proteins are considered lower-quality protein sources than animal proteins due to their lower amount of essential amino acids (EAA) and only containing trace amounts of creatine. The purpose of this study was to determine whether ingestion of military-style meals-ready-to-eat (MREs) containing plant-based (Plant) or pork-based (Pork) sources or protein would affect recovery after the Army Combat Fitness Test (ACFT).
Methods
Twenty-three (n = 23) Corps of Cadets members participated in a randomized, double-blind, placebo-controlled, and crossover-designed study where they consumed Plant or Pork protein containing MREs. On testing days, participants donated a blood sample and consumed a pre-exercise meal on testing days. After four hours, participants performed the ACFT. Participants were then fed 3 MREs daily containing ≈ 1,250 kcals, 145 g carbohydrate, 45 g protein, 60 g fat, providing 1.7 g/kg/d of protein. Plant-based MREs contained 15.2 g/d (0.20 g/kg/d) of EAA and 0.215 g/d (0.003 g/kg/d of creatine) compared to 22.9 g/d (0.31 g/kg/d) of EAA and 1.82 g/d (0.024 g/kg/d) of creatine in the pork-based MREs. Participants returned to the lab in a fasted condition at 0600 after 24, 48, and 72 hours of recovery while being fed 3 MREs daily and having markers of recovery assessed. On day 3, participants repeated the ACFT four hours after consuming an MRE. Data were analyzed using general linear model statistics and percentage changes from baseline with 95% confidence intervals.
Results
Univariate analysis revealed no significant interaction effects (p > 0.05) between treatments in performance variables. However, the percentage change from baseline analysis showed that participants improved hand-release push-up repetitions (Pork 5.0% [1.1, 8.9], p = 0.013; Plant 5.4% [1.5, 9.3], p = 0.007) and plank test time (Pork 18.8% [4.7, 32.9], p = 0.010; Plant 14.8% [0.6, 28.9], p = 0.041). Two-mile run times were faster with the Plant (−3.8% [−6.4, −1.1], p = 0.006), while non-significantly decreased with Pork (−2.0% [−4.7, 0.6], p = 0.125). Total ACFT score values (Pork 22.9 [5.9, 39.9], p = 0.009; Plant 12.9 [−4.1, 29.9], p = 0.134) increased from baseline with Pork (see Figure 1).
Conclusion
Results provide some evidence that the protein quality of the MREs can affect recovery and performance from intense military-style exercise. MREs should contain high-quality protein sources or be supplemented with 6–10 g/d of EAA and 2–3 g/d of creatine monohydrate to offset dietary deficiencies, particularly in military personnel following a plant-based diet. Registered clinical trial #ISRCTN47322504.
KEYWORDS: Mres, protein source, recovery, military fitness