Obesity is an important public health problem, which is directly related to the risk of childhood complications and the increase of incidence rate and mortality of adult complications. The consequences are more serious than malnutrition such as low weight. Since the 1980s, the obesity rate among children in China has gradually increased. Currently, overweight and obesity are important health issues for children in rural and urban areas of China, with obesity rates in many large cities approaching or exceeding those in developed countries. The Report on Nutrition and Chronic Disease Status of Chinese Residents (2020) shows that the overweight and obesity rate among children aged 6-17 in China has approached 20%, with 10% of children under 6 years old. The imbalance between energy intake and expenditure is the direct cause of individual overweight and obesity. The 2021 "Healthy Children Action Plan (2021-2025)" explicitly requires the implementation of early screening, early diagnosis, and early treatment prevention and control strategies for risk factors such as obesity that seriously endanger children's health, reducing disease burden, promoting children's health, emphasizing the principle of prevention first and combining prevention and treatment. Given the current status of children's nutrition and health in China, it is an urgent need to establish a standardized and regulated monitoring and management system for obesity and overweight in preschool children, as well as service standards, for the development of children's health. This project aims to establish a complete prevention, improvement, and intervention promotion plan for obesity and overweight in preschool children, as well as a comprehensive monitoring and management system that combines medicine, education, home, and community. It will strengthen children's nutrition feeding and exercise guidance, reduce sedentary time, promote food and movement balance, and prevent and reduce childhood overweight and obesity. Provide children with comprehensive, full process, and warm children's healthcare clothing, and provide small-scale policy research references for the implementation of support systems for children's nutrition improvement projects.

1. Procedures. Step 1: Epidemiological survey: Conduct a health survey on preschool children in selected kindergartens to understand the prevalence and risk factors of overweight and obese children; Phase 2: Recruit overweight and obese children from kindergartens with a population of over 200 in Chongqing, and randomly divide them into an intervention group and a blank control group. Dietary and exercise management, combined with reward and support mechanism monitoring, were implemented for the intervention group, while the blank control group did not receive the aforementioned interventions. Measure the height, weight, BMI, questionnaire survey, blood indicators, etc. of the children before and after the intervention, and use them as evaluation indicators.
2. The sample size for comparing the means of the two groups is N=(Z α/2+Z β) 2 σ 2 (Q1-1+Q2-1)/δ 2. If the difference in BMI decrease between the two groups after intervention is 0.58, and if σ=1.2 and α is taken as 0.05 on both sides, the test power is 0.8, Q1=Q2=0.5，σ=1.2，δ=0.58，Z0.05/2=1.96，Zβ=0.842， Calculate N=(1.96+0.842) 2 * 1.22 * (0.5-1+0.5-1)/0.582 ≈ 69, taking into account the situation of loss to follow-up and refusal to follow up at 20%. The final required two groups of research subjects are 87, and a total of at least 174 research subjects will be included.

4. Statistical analysis. SPSS 26.0 software was used for statistical analysis, and descriptive statistics were performed on general demographic data. Count data was expressed as n (%), and inter group comparisons of rates were performed using a 2-test. Continuous variables that followed a normal distribution were described as mean ± standard deviation (x ± s), and inter group comparisons were performed using t-test. All tests were two-sided, and the test level α was set to 0.05. Multivariate logistic regression analysis of the correlation between nutritional status and risk factors. Using rank sum test to compare the differences in various indicators before and after intervention in obese and overweight children.

5.Ethical matters and data protection. The patients participated in the study will sign the informed consent (obtained from the guardian). And this study was approved by the local ethics committee. Patient's name will be abbreviated and the research data will be assigned a code then to provide to the researcher. The authorization from parents on the patient's health information remains valid until the study is completed. After that, researchers will delete private information from the study record.

Inclusion Criteria:

overweight or obese Children Currently, there are no projects related to overweight and obesity management (such as weight loss management, etc.) Parents and children are willing to accept dietary and exercise management for a period of 4 months Willing to measure height, weight, BMI, blood pressure, body composition, questionnaire survey (exercise, diet, etc.) and other items before intervention and 1 month, 2 months, 3 months, and 4 months after intervention (a total of 5 times) Willing to undergo blood tests before and 4 months after intervention (2 times in total); The questionnaire information is filled in accurately and meets the questionnaire quality control standards

Exclusion Criteria:

Recruiter exclusion criteria:

Preschool children with underlying diseases (such as congenital heart disease, liver and kidney disease, thyroid disease, malignant tumors, etc.) or uncontrolled underlying diseases

Questionnaire exclusion criteria:

Incorrect information filling in the questionnaire, which does not meet the questionnaire quality control standards

Data is confidential during the study.