Effect of different post-exercise sugar diets on the rate of muscle glycogen synthesis

Dietary macronutrient recommendations for optimal recovery post-exercise: Part I

“…For example, Van Loon et al 53 demonstrated a ~ 200% increase in the rate of glycogen synthesis when CHO intake was increased from 0.8 to 1.2 g/kg BW/hour (~ 145% higher than Blom et al 3 and Ivy et al 29 ). Several others have reported even higher rates of muscle glycogen synthesis (~ 170% higher) when 1 -1.7 g CHO/kg BW/hour was ingested at 15 -60-minute intervals during a 3 -4-hour recovery period.…”

“…Blom and co-workers 3 found that the ingestion of glucose (high GI) and sucrose (moderate GI) feedings after prolonged exercise increased the rate of glycogen synthesis significantly higher at 6 hours post-exercise compared with fructose (low GI) feeding. Surprisingly, sucrose (moderate GI), which contains equimolar amounts of fructose (low GI) and glucose (high GI), resulted in similar rates of glycogen synthesis and muscle glycogen levels than a similar amount of glucose (high GI).…”

“…4,19,55 However, restoration of muscle glycogen in the post-exercise period takes precedence over liver glycogen restoration, which, even in the absence of dietary CHO supply, can occur at a low rate (~ 1 -2 mmol/kg wet weight (ww)/hour), with some of the substrate being provided through gluconeogenesis. 3 Therefore, Part I of this article focuses on aspects increasing the rate of muscle glycogen recovery specifically.…”

“…36 However, in the absence of CHO ingestion, these exercise-induced increases in glycogen synthase and GLUT-4 availability (and hence the potential for glucose transport) may decline rapidly. 12,23 When considering the ideal amount of CHO to be ingested, Blom et al 3 demonstrated an increase in muscle glycogen synthesis rate of ~ 150% when post-exercise CHO intake was increased from 0.18 to 0.35 g/kg body weight (BW)/hour (provided at 2-hourly intervals post-exercise), but no further increase when CHO intake was increased to 0.7 g/kg BW/hour. Similarly, Ivy et al 29 found no difference in muscle glycogen synthesis rate between the ingestion of 0.75 vs. 1.5 g CHO/kg BW/hour (provided at 2-hourly intervals) over a 4-hour period post-exercise.…”

“…31,42,53 In these studies, the CHO beverages were provided at 15 -60-minute intervals post-exercise, as opposed to 2-hourly intervals as in the studies where no difference in rates of muscle glycogen synthesis were found. 3,29 Additionally, Ivy et al 29 reported that if beverages are provided on a 2-hourly basis, then a CHO intake of > 0.5 g CHO/kg BW/hour is needed in order to maximise glycogen synthesis post-exercise.…”