Pre-Exercise Protein and Caffeine Ingestion Has No Detectable Effect on Respiratory Exchange Ratio Following High-Intensity Resistance Training in Overweight Females

Nutritional habits prior to exercise can influence metabolic processes both during and after an exercise bout. Due to the negative impact of excess body fat on metabolic health, pre-exercise nutrition and exercise interventions that target improved fat oxidation following exercise are warranted. The purpose of this study was to examine the combined effects of pre-exercise nutrition interventions and high-intensity resistance training (HIRT) on post-exercise substrate utilization in overweight (OW) females. Respiratory exchange ratio (RER) was measured in 15 recreationally active OW females at baseline (BASE), immediately post (IP), 30 min (30), and 60 min (60) post-HIRT following ingestion of the following supplements: carbohydrate (CHO), protein (PRO), CHO+CAFF (3 mg/kg body mass), or PRO+CAFF in a randomized, crossover, double-blind design. RER was not significantly different between any of the nutrition interventions (all p > 0.05). However, independent of pre-exercise nutrition ingestion, RER was significantly lower at 30 (0.75 ± 0.05; p < 0.01) and 60 (0.74 ± 0.05; p < 0.01) post-exercise in comparison to BASE (0.81 ± 0.05) and IP (0.78 ± 0.06). Collectively, RER decreased during recovery following HIRT in OW females, regardless of pre-exercise nutrition habits.