Post-exercise protein-carbohydrate and carbohydrate supplements increase muscle glycogen in males and females

We have shown that females did not increase intra-muscular glycogen in response to an increased percentage of dietary carbohydrate (CHO) (60 → 75% of EIN)(Tamopolsky, et al., JAP 78:1360-8, 1995). CHO and CHO/protein (PRO) supplementation post-exercise can potentiate glycogen resynthesis as compared to placebo (Zawadski, et al., JAP 72:1854-9, 1992). This may be a method for females to maximize muscle glycogen storage. We studied the effect of isoenergetic CHO and CHO/PRO supplements upon muscle glycogen resynthesis in the first 4 hours after endurance exercise (90 min @ 65 % VO2peak) in trained male (N=8) and female (N-9) endurance athletes. Each subject completed 3 trials separated by ∼ 3 weeks: A - CHO = 1 g/kg; B - CHO = 0.75 + PRO = 0.1 g/kg (+ FAT to isoenergetic); C - PLACEBO (PL) = artificial sweetener; immediately and +1 h post-exercise. Subjects were given pre-packaged, isoenergetic, isonitrogenous diets for the day prior to and during the exercise trial individualized to their habitual diet. Females oxidized more lipid during exercise as compared to males (P < 0.05) Both of the supplement trials resulted in greater post-exercise glucose and insulin as compared to PL (P < 0.01) with no gender differences. Similarly, both trials resulted in increased glycogen re-synthesis (CHO = 37.2; CHO/ PRO = 24.6 mmol/kg(d.m.)/h) as compared to PL = 7.5 mmol/kg(d.m.)/h (P < 0.001) with no gender differences. We conclude that post-exercise CHO and CHO/PRO nutritional supplements can increase glycogen re-synthesis to a greater extent than placebo for both males and females (Supported by Mead-Johnson, Canada).