Effect of Meal Timing after Resistance Exercise on Hindlimb Muscle Mass and Fat Accumulation in Trained Rats

To study the effect of meal timing after exercise on body composition, 20 male rats were assigned to either a group fed a meal right after exercise (R) or a group fed a meal 4 h after exercise (L). Resistance exercise (squatting) was conducted from 6:00 to 7:00, 3 d/wk for 10 wk. Meals were consumed from 7:00 to 8:00 and from 19:00 to 20:00 for R, and from 11:00 to 12:00 and from 19:00 to 20:00 for L. The room was lighted from 7:00 to 19:00. After 10 wk, the body weight was comparable between the groups. The hindlimb muscle weight was higher in R than in L by 6% (p<0.05), whereas the sum of the weight of perirenal, epididymal, and mesenteric adipose tissues was lower in R than in L by 24% (p<0.01). The soleus lipoprotein lipase (LPL) activity was higher in R than in L by 70% (p<0.01), and the activity negatively correlated with the adipose tissue weight (r=-0.49, p<0.05). These results suggest the possibility that ingesting a meal right after resistance exercise may contribute to an increase in the muscle mass and to a decrease in the adipose tissue compared to ingesting a meal several hours later.