Fast Food Ingestion for Lunch Delays Postprandial Lipid Metabolism in Young Women

We investigated the effect of fast food on diurnal lipid and carbohydrate profiles in healthy young Japanese women. Eight healthy young women with the apolipoprotein E3/3 phenotype were studied on two occasions in a randomized crossover design. On one occasion, the subjects consumed common foods at breakfast (9:00), lunch (13:00), and dinner (19:00) (C trial). On the other occasion, they consumed common foods at breakfast and dinner, but they consumed fast food (a cheeseburger, fried potatoes, and cola) at lunch (F trial). Blood samples were taken at 9:00, 11:00, 13:00, 15:00, and 19:00, and at 9:00 the next morning. In the C trial, the serum triglyceride (TG) concentration at 19:00 was significantly lower compared with that at 13:00, but in the F trial, it was significantly higher at 15:00, 17:00, and 19:00 compared with that at 13:00. The incremental area under the curve for TG (∆AUC-TG) (13:00 to 9:00 the next morning) in the F trial was significantly larger than that in the C trial. The concentration of fasting remnant lipoprotein-cholesterol (RemL-C) the next morning was positively correlated with ∆AUC-TG (13:00 to 9:00 the next morning). In conclusion, compared with the conventional diet, the intake of fast food at lunch delayed the postprandial TG metabolism and the serum TG concentration did not return to baseline (before lunch) even before dinner in healthy young Japanese women.