Isoenergetic pre-exercise meals varying in carbohydrate similarly affect resistance training volume performance compared to placebo

Carbohydrate is an important fuel during moderate-to-high-intensity exercise. We hypothesised that pre-exercise carbohydrate ingestion would improve resistance training (RT) volume performance. In a cross-over design, sixteen resistance-trained participants (male = 13, female = 3) performed 3 sets of back squats, bench press, prone row, and shoulder press to repetition fatigue at 80% of 1-repetition maximum (~90min). Two hours prior, in randomised order, participants ingested high carbohydrate (HCHO; 1.2g/kg body mass), low carbohydrate (LCHO; 0.3g/kg body mass), or low-calorie placebo (PLA), taste and texture matched liquid breakfasts. Linear mixed models were used to analyse volume performance, subjective appetite ratings, and blood glucose and lactate. There were no significant differences between conditions for repetitions completed per session (p = 0.318) or exercise (p = 0.973). Pre- and post-exercise hunger was similar between conditions (p = 0.155). Satiation was greater in HCHO and LCHO versus PLA post-breakfast (p = 0.007 and p = 0.002, respectively) and pre-exercise (p = 0.001 and p = 0.002). Fullness was greater in HCHO and LCHO versus PLA post-breakfast (p = 0.001 and p = 0.001, respectively) and pre-exercise (p < 0.001 and p < 0.001). Blood lactate was greater mid- (p < 0.001) and post-exercise (p < 0.0001) and was similar between conditions (p = 0.897). Blood glucose significantly increased 30-mins after breakfast in HCHO versus LCHO and PLA (p < 0.001) and was similar between conditions post-exercise (p = 1.000). The macronutrient or energy composition of a pre-exercise meal does not enhance upper-body dominant RT volume.