The prevalence of overweight and obesity among children and adolescents is continuously rising. As countries have developed several school-based nutrition policies to control overweight and obesity, it is important to examine the effectiveness of nutrition policies.

To evaluate the effect of the centralized distribution of food material system on overweight and obesity rates among children and adolescents aged 6-15 years.

In April 2023, a total of 104 749 BMI data from sixteen schools aged 6 to 15 years (8 schools were included in the unified food distribution system and recorded as the unified distribution group, and 8 schools were not included in the unified food distribution and supply system and recorded as the non-unified distribution group) in Wuxi were retrospectively collected between 2017 and 2021. The data of physical examination was collected from Student Health Monitoring System in Jiangsu Province. The overweight and obesity epidemiologic trends among children and adolescents were analyzed from 2017 to 2021 in Wuxi, and the changes in BMI-Z scores and trends in overweight and obesity rates among children and adolescents were compared before and after the implementation of the centralized distribution of food material system by the Joinpoint regression and grey GM (1, 1) model.

The prevalence of overweight and obesity among in children and adolescents aged 6-15 years was increasing from 2017 to 2021. The results of the Joinpoint regression analysis indicated that the prevalence of overweight (APC 1.8% vs 4.6%) and obesity (APC 6.9% vs 13.3%) among students included in the system exhibited a slower rate of increase than among those not included. The disparity in the increase of BMI-Z scores among students included in the system and those not included changed from -0.055 (95%CI=-0.108--0.002) to -0.195 (95%CI=-0.246--0.145) before and after the implementation of the system. The results of grey GM (1, 1) model showed that the incidence rate of overweight among children and adolescents in Wuxi in 2022, 2023 and 2024 was 22.02%, 22.39% and 22.77% respectively, with the incidence rate of overweight being 17.02%, 18.50% and 20.12% respectively.

The increasing trend in the prevalence of overweight and obesity, as well as the increase in BMI-Z scores among children and adolescents, has slowed down after the implementation of the centralized distribution of food material system. The system may be an effective method of improving the nutritional status of children and adolescents. Therefore, it is recommended that the centralized distribution of food material system still needs to be implemented and the monitoring area needs to be expanded.

儿童青少年超重率和肥胖率正持续增加，各国制定了多个以学校为基础的营养政策来控制超重肥胖，调查营养政策的实施效果较重要。

评价学校食材统一配供体系对6~15岁儿童青少年超重率和肥胖率的影响。

于2023年4月回顾性收集2017—2021年无锡市16所学校（8所学校纳入食材统一配供体系记为统一配供组，8所学校未纳入食材统一配供体系记为非统一配供组），共计104 749人次6~15岁学生BMI监测数据，体检数据来源于江苏省学生健康监测系统。采用Joinpoint回归和灰色GM（1，1）模型分析2017—2021年超重率和肥胖率的变化趋势，比较食材统一配供体系实施前后儿童和青少年的体质指数Z（BMI-Z）评分的变化以及超重率和肥胖率的趋势。

2017—2021年6~15岁儿童青少年超重率和肥胖率均呈上升趋势，Joinpoint回归分析显示，统一配供组的学生超重（APC：1.8% vs 4.6%）和肥胖率（APC：6.9% vs 13.3%）上升速度较非统一配供组的学生低，体系实施前后，统一配供组学生与非统一配供组学生的BMI-Z评分增幅差由-0.055（95%CI=-0.108~-0.002）变为-0.195（95%CI=-0.246~-0.145）。灰色GM（1，1）模型预测结果显示，2022、2023、2024年无锡儿童青少年超重率分别为22.02%、22.39%、22.77%，肥胖率分别为17.02%、18.50%、20.12%。

实施学校食材统一配供体系后，儿童青少年的超重肥胖上升趋势及BMI-Z评分增幅有所减缓，该体系可能是改善儿童青少年营养状况的有效方法，需要继续实施并扩大监测面。