Non-alcoholic fatty liver disease (NAFLD) in children and adolescents has recently been renamed metabolic dysfunction-associated steatotic liver disease (MASLD). It has become one of the leading chronic liver diseases in children. The prevalence of MASLD is 6.3% among the general pediatric population and 40.4% among overweight and obese children, with an increasing trend each year. MASLD increases the risk of various metabolic diseases and can eventually lead to liver fibrosis or hepatocellular carcinoma, contributing to the disease burden.

Previous work by our project team using machine learning methods has identified that fasting insulin, alanine aminotransferase (ALT), and waist-to-height ratio (WHtR) have good predictive value in overweight and obese children, with a recommendation that children with a WHtR ≥ 0.48 should undergo further screening. However, external validation is still required to improve the effectiveness and cost-efficiency of this screening approach.

Till now, there are no approved drug treatments for paediatric MASLD, and lifestyle interventions (such as restricting energy intake and increasing physical activity) are the main therapeutic strategies. However, existing studies face limitations, such as small sample sizes, diverse intervention methods, lack of standardization, and short intervention durations, which hinder their clinical application. Therefore, it is essential to explore effective health lifestyle intervention models tailored to children.

This study aims to: First, optimizing the screening and treatment pathway, assess the cost-effectiveness and applicability of WHtR as a screening tool, and develop a tiered screening system suitable for Chinese children; Second, integrating school, clinic, family, and community resources to establish a multifacted lifestyle intervention model and evaluate its efficacy.

Inclusion Criteria:

• parents agree and support their children's weight loss, and students and parents have informed consent;
• students in two to four grade aged 7 and 11 years old;
• students with WHtR ≥ 0.48.

Exclusion Criteria:

• medical history of heart disease, hypertension, diabetes, tuberculosis, asthma, virus hepatitis or nephritis;
• obesity caused by endocrine diseases or side effects of drugs;
• abnormal physical development like dwarfism or gigantism;
• physical deformity such as severe scoliosis, pectus carinatum, limp, obvious O-leg or X-leg;
• inability to participate in school sport activities;
• a loss in weight by vomiting or taking drugs during the past 3 months.