Abstract: Objective To explore the characteristics of intestinal flora in obese preschoolers, and to analyze the intake of different kinds of food in preschoolers. Methods Obese children were selected as the study group by convenient sampling method, and non-obese children of the same gender and age ± 0.5 years were selected as the control group. Fresh feces of two groups of children were collected in the morning, and fecal DNA samples were extracted with fecal DNA genomic extraction kit. Polymeric chain reaction （PCR） was used to detect intestinal flora. The 24-hour dietary review method was used to investigate the food intake of children on the first day by their parents, and the daily food intake of children was evaluated according to the relevant standards of Practical Child Nutrition. The descriptive analysis method was used to compare the characteristics of intestinal flora and food intake of the two groups. Results A total of 790 obese children （study group） were included in this study, including 458 boys and 332 girls, with an average age of （4.15±0.54） years. There were 784 non-obese children （control group）, including 447 boys and 337 girls, with an average age of （4.16±0.61） years. There were no significant differences in gender distribution and an average age between the two groups （all P > 0.05）. The Proteobacteria content of the study group appeared significantly higher than that of the control group, and the differences between the groups were statistically significant （P<0.01）, whereas the rest of the two groups, such as Firmicutes, Bacteroidetes, Actinobacteria, and other genera, showed no significant differences （all P > 0.05）. The children in the study group had significantly higher intakes of oils and fats than the children in the control group, with statistically significant differences （P<0.01）, and the compliance rate of vegetable, grain, and dairy intake was significantly lower than that in the control group, while the compliance rate of egg products intake was higher than that in the control group, and the differences between groups were statistically significant （all P<0.01）. The rate of excessive intake of meat and egg products in the study group was significantly higher than that in the control group （all P<0.01）. Conclusions Most obese preschoolers have an imbalance of intestinal flora, mainly with the increase of Proteobacteria. At the same time, compared with healthy children, obese preschoolers have a higher intake of fat, a higher rate of excessive intake of meat and egg products, and an insufficient intake of vegetables, grains, and dairy products. It is suggested that obese preschoolers should take lifestyle intervention by adjusting their diet structure or taking probiotics, to improve their obesity status.

Key words: Preschooler, Obesity, Characteristics of intestinal flora, Dietary structure, Excessive intake