SummaryTo 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 4h after exercise (L). Resistance exercise (squatting) was conducted from 6:00 to 7:00, 3d/wk for 10wk. 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 10wk, 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.

SummaryWe hypothesized that bone acquisition was affected by the timing of meal intake after resistance exercise training. This was based on the following previous results: 1) Nutrient intake right after exercise resulted in an increase in muscle mass and a decrease in abdominal fat mass as well as muscle protein synthesis when compared to the intake of a meal later after the exercise; and 2) body composition has been proposed to be a good predictor of bone mass. To substantiate our hypothesis, 20 male rats were assigned to either a group fed a meal right after squat exercise (R) or a group fed a meal 4h after the exercise (L). The 10-wk training program consisted of approximately 70% of one repetition maximum for each animal, 15 repetitions per set, 10 sets per day, 3d per week. As a result, hindlimb muscle mass in the R group was greater (p<0.05) than that in the L group and abdominal fat mass was less (p<0.01) in the R group as compared to the L group, regardless of there being no significant difference in body weight between the groups. Bone volume in the tibia (p<0.01) and femur (p<0.05) were both significantly greater in the R group than in the L group. Bone mineral content index (BMCI) and bone mineral density index (BMDI) in the tibia of the R group were significantly (p<0.05) greater than the corresponding values of the