Hyperlipemic response of young trained and untrained men after a high fat meal

To test the hypothesis that endurance training is associated with a decreased lipemia after a high fat meal, 16 young men [22 to 34 years old, nine of whom were trained (T) and seven of whom were untrained (UT)] were recruited. T ran greater than 30 or biked greater than 100 miles a week, while UT had been sedentary for at least the preceding 3 months. Daily caloric intake and daily caloric expenditure during exercise were 35% and 704% greater, respectively, in T than in UT. VO2max was 31% greater, while percent body fat was 36% lower in T than in UT. Dietary composition and body height and weight were similar. After a fasting blood sample was taken, the men ate a high fat meal (approximately 56% of total calories as fat in 1100 kcal adjusted to body weight), and additional blood samples were taken hourly for 8 hours. Fasting lipids were similar. Postprandial peak triglyceride (TGmax), percent TG increase (%TGI), and total lipemic response (TLR, the area under the lipemia curve in excess of fasting TG) were 42%, 54%, and 75% greater, respectively, in UT vs. T. Stepwise regression analysis showed that the same three-variable model (training status, fasting TG, and VO2max) described the variation in TGmax (R2 = 0.97), %TGI (R2 = 0.75), and TLR (R2 = 0.92). Furthermore, this same analysis showed that after adjustment for fasting TG and VO2max, the UT group had a significantly greater postprandial lipemia whether expressed as TGmax (p less than 0.0001), %TGI (p = 0.0002), or TLR (p = 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)