ObjectiveTo find the type of dietary structure that can effectively prevent or improve postprandial sleepiness in the Chinese population， and provide scientific basis and solutions for improving or avoiding postprandial sleepiness. MethodsIn this study， a six-day dietary intervention trial was conducted for 20 volunteers on four different diets （normal diet， high-fat diet， high-carbohydrate diet and healthy diet）. ResultsThe results showed that sleepiness increased after all four types of meals， but decreased after 30 minutes in the healthy balanced diet group； meanwhile， it increased for 60 minutes before it declined in the high-carbohydrate， high-fat， and normal diet （control） group. At 60 minutes after meal， the drowsiness of the healthy balanced diet group was the weakest， and that of the high carbohydrate diet groups was the strongest， while that of the normal diet group and the high fat diet group was intermediate （P<0.000 1）. Postprandial sleepiness was positively correlated with intake of carbohydrate and manganese， and negatively correlated with intake of protein， some mineral elements and vitamins. ConclusionThese results suggest that controlling carbohydrate and fat intake and appropriately increasing the intake of mineral elements and vitamins in a healthy and balanced diet can significantly improve and prevent postprandial sleepiness.