About 2.6 billion people ( about 40 % of the world 's population ) are affected by overweight or obesity. The prevalence of overweight and obesity in Chinese adults has exceeded 50 %, and the prevalence is still on the rise.The gut microbiota is regarded as an endocrine organ and participates in energy balance. Diet changes can disrupt the relationship between the microbiota and the host, leading to metabolic diseases.Although human studies provide important information, there are limitations, such as the entry of complex gastrointestinal environment limiting components, the lack of dynamic microbial process information, and the uncertainty of drug side effects. In vitro methods can solve these problems, allowing dynamic sampling, standardized operation, high repeatability, and evaluation of potential toxins and pathogens. In vitro models are widely used to evaluate the effects on the human colon microbiome and to predict in vivo results.Based on the above research background, this study aims to collect fecal samples from obese people to construct an in vitro intestinal microbial ecological simulation system. This will lay an experimental foundation for further exploring the effect of specific nutrient intervention on the composition and function of gut microbiota in obese people.

Inclusion Criteria:

• Screening in the physical examination population who intend to retain fecal samples in the physical examination center of our hospital. BMI ≥ 28, age range from 18 to 30.

Exclusion Criteria:

• Previous history of intestinal disease, history of hypertension, diabetes, coronary heart disease and other chronic diseases, history of important organ disease or surgery, history of malignant tumor disease.
• He had a history of heavy smoking and alcohol abuse.
• In the past 6 months, she took antibiotics.
• Weight loss measures in the past 6 months, including but not limited to dieting, physical exercise, probiotic intervention and other medications.
• Subjects and their families who disagreed with the study protocol.

samples in the physical examination center of our hospital. BMI ≥ 28, age range from 18 to 30.