Fluid, energy and nutrient recovery via ad libitum intake of different fluids and food

Introduction This study compared the effects of ad libitum consumption of different beverages and foods on fluid retention and nutrient intake following exercise. Methods Ten endurance trained males (mean ± SD; Age = 25.3 ± 4.9 years, VO₂max = 63.0 ± 7.2 mL·kg·min^− 1) performed four trials employing a counterbalanced, crossover design. Following 60 min of exercise (matched for energy expenditure and fluid loss) participants consumed either water (W1 and W2), a sports drink (Powerade® (P)) or a milk-based liquid meal supplement (Sustagen Sport® (SS)) over a four hour recovery period. Additionally, participants had access to snack foods on two occasions within the first 2 h of recovery on all trials. All beverages and food were consumed ad libitum. Total nutrient intake, urine volume, USG, body weight as well as subjective measures of gastrointestinal tolerance and thirst were obtained hourly. Plasma osmolality was measured pre, post, 1 and 4 h after exercise. Results Total fluid volume ingested from food and beverages in W1 (2.28 ± 0.42 L) and P (2.82 ± 0.80 L) trials were significantly greater than SS (1.94 ± 0.54 L). Total urine output was not different between trials (W1 = 644 ± 202 mL, W2 = 602 ± 352 mL, P = 879 ± 751 mL, SS = 466 ± 129 mL). No significant differences in net body weight change was observed between trials (W1 = 0.01 ± 0.28 kg, W2 = 0.08 ± 0.30 kg, P = − 0.02 ± 0.24 kg, SS = − 0.05 ± 0.24 kg). Total energy intake was higher on P (10,179 ± 1484 kJ) and SS (10,577 ± 2210 kJ) compared to both water trials (W1 = 7826 ± 888 kJ, W2 = 7578 ± 1112 kJ). Conclusion With the co-ingestion of food, fluid restoration following exercise is tightly regulated and not influenced by the choice of either water, a carbohydrate-electrolyte (sports drink) or a milk-based beverage.