Increment of glycogen contents in liver and skeletal muscle resulting from feeding pattern of a large meal eaten just before a resting period

We investigated the effect of a large meal eaten just before a resting period on liver and skeletal muscle glycogen content using female rats (n = 30). The rats were divided into three groups; a group eating a large meal just before a resting period (BR), a group eating a large meal just before an active period (BA), and a group for ad libitum feeding (AD). All of the rats were allowed to run voluntarily on a stainless steel wheel from 20:00 to 07:00 hours. The BR group of rats were fed a large meal (the maximal amount of diet that rats could consume for 1 hour; more than 12 g) between 07:00 and 08:00 hours and small meal (3 g) between 19:00 and 20:00 hours, the BA group of rats were fed a large meal (the maximal amount of diet that rats could consume for 1 hour; more than 12 g) between 19:00 and 20:00 hours and a small meal (3 g) between 07:00 and 08:00 hours. After 5 weeks, half of the rats in each group were sacrificed at 22:00 hours (in the active period), and the other half of the rats at 07:00 hours (in the resting period) to measure glycogen content in liver and gastrocnemius muscle. 1) The liver glycogen content in the active period was significantly greater in the BR group than in the BA and AD groups. The content in the resting period was significantly less in the BR group than in the BA and AD groups. 2) The liver glycogen content 2 hours after a large meal was not significantly different between the BR and BA groups, but 14 hours after a large meal it was significantly greater in the BR group than in the BA group. 3) The gastrocnemius muscle glycogen content in the active period was significantly greater in the BR group than in the BA and AD groups. The glycogen content in the resting period was also significantly greater in the BR group than in the BA group. 4) The gastrocnemius muscle glycogen content at both 2 and 14 hours after the large meal was significantly greater in the BR group than in the BA group. These results indicate that a large meal eaten just before a resting period increases liver and skeletal muscle glycogen content in the active period compared to a large meal eaten just before an active period. This suggests that eating a large meal just before a resting period may enhance metabolic capacity for endurance exercise.