Influence of timing of sucrose meal feeding and physical activity on plasma triacylglycerol levels in rat.

The present study was undertaken to determine whether the timing of sucrose meal feeding relative to periods of physical activity affects plasma triacylglycerol (TG) levels in rats. Animals were daily meal-fed on a basal diet and a 35% sucrose diet for 10 weeks. Meal times were at 08.00-09.00 hr and 21.00-22.00 hr. Voluntary running in wheels was allowed between 22.00-08.00 hr, but was restricted from 08.00 to 22.00 hr. The sucrose diet was given at the morning meal time to one group (M-S eaters) and at the evening meal time to another group (E-S eaters). The timing of the sucrose meal did not have any influence on consumption of either of the two diets, physical activity, weight gain, or the weight of several organs and tissues. Plasma TG, however, was significantly higher in the M-S eaters than in the E-S eaters. Lipoprotein lipase activity of several tissues was not affected by the timing of the sucrose meal. The Triton-induced increase in fasting plasma TG was significantly higher after the sucrose meal than after the basal meal regardless of the timing of the sucrose diet. The TG accumulation rate during the physically inactive period was significantly greater in the M-S eaters than in the E-S eaters, while during the physically active period it was equal in both groups. These results suggest that the effect of sucrose feeding on plasma TG may be conditioned by the timing of sucrose feeding and rats' physical activity.