The gastrointestinal tract harbors a complex microbiota,which contains almost 30 genera,400 to 500 species.The factors influencing human intestinal microbiota include host and environmental ones,with the most important environmental factor being diet.Dietary fiber,fat,and protein have different impact on gastrointestinal microbiota and the microbiota in turn plays an important role in maintaining health.Its variation can lead to many diseases.Knowledge of the interaction between diet and gastrointestinal microbiota may be conducive to reaching a better understanding of some diseases,and to discovering better preventive and therapeutic strategies.