Prior Exercise Does Not Reduce Postprandial Lipemia Following a Mixed Glucose Meal When Compared with a Mixed Fructose Meal

This study examined the effect of prior exercise on postprandial lipemia (PPL) concentration following a mixed meal (MM) made with either glucose or fructose. Sedentary women completed four trials in random order: 1) Rest-Fructose: RF, 2) Rest-Glucose: RG, 3) Exercise-Fructose: EF, 4) Exercise-Glucose: EG. Exercise expended 500 kcal while walking at 70%VO2max. Rest was 60 min of sitting. The morning after each trial, a fasting (12 hr) blood sample was collected followed by consumption of the MM. The MM was blended with whole milk and ice cream plus a glucose or fructose powder. Glucose and fructose powder accounted for 30% of the total kcal within the MM. Blood was collected periodically for 6 hr post-MM and analyzed for PPL. Magnitude of PPL over the 6 hr postmeal was quantified using the triglyceride incremental area under the curve (TG AUC(I)). Significant differences (p < .05) between trials were determined using repeated-measures ANOVA and Bonferroni post hoc test. There was no significant difference in the TG AUCI between the four trials (p > .05). A significant trial by time interaction for TG concentration was reported (p <.05). Despite lack of change in the AUCI with prior exercise, the lower TG concentration at multiple time points in the EG trial does indicate that prior exercise has some desirable effect on PPL. This study suggests that replacing fructose with glucose sugars and incorporating exercise may minimize PPL following a mixed meal but exercise will need to elicit greater energy expenditure.