Table_1_Effectiveness of current protein recommendations in adolescent athletes on a low-carbon diet.XLSX

Adolescent athletes require adequate energy and nutrient supply to support growth, development, and the demands associated with exercise and training. However, they are susceptible to nutritional inadequacies affecting their health and physical performance. Food choices with nutrient adequacy and environmental protection is crucial for a sustainable diet. Therefore, we aimed to assess the adequacy of low-carbon diets to meet the protein requirements of adolescent athletes. Therefore, a cross-sectional observational study was conducted with 91 adolescent athletes from sports clubs in Rio de Janeiro who underwent anthropometric and food consumption assessments. To estimate the environmental impact of anthropogenic activities, the sustainability indicators carbon footprint (CF) and water footprint (WF) were used. The CF of the athlete's diet was compared with the benchmark of 1,571 g CO2eq/cap/d estimated by the World Wildlife Fund (WWF). Protein recommendations according to the American Dietetic Association (ADA) for athletes and protein food groups according to the low-carbon EAT-Lancet reference diet were used as references. The results were stratified by sport modality, age, sex, and income range. The Mann-Whitney test was performed, followed by the Kruskal-Wallis test with Dunn's post-hoc test to assess the differences between groups using the statistical program GraphPad PRISM® version 8.0. CF and WF were directly associated with total energy intake, total protein intake, animal-origin protein intake, and the food groups of meat and eggs. Significant differences were observed in the environmental impact of diet based on sports groups and gender. The athletes' profile with higher environmental impact was male, middle-income class, and of any age group. The quartiles of CF of the overall diets were above the 1,571 g CO2eq/cap/d benchmark. Additionally, ADA's recommended range of daily protein consumption was met by most athletes, even in the lowest quartile of CF. Thus, a diet with a lower environmental impact can meet protein recommendations in adolescent athletes. The results found are of interest to the sports and food industries. It could help in designing a balanced diet for athletes as well as ensure less negative environmental impacts of food production and consumption.青少年运动员需要充足的能量与营养供给，以支撑生长发育及运动训练相关的生理需求。然而该群体易出现营养不足问题，进而损害健康并影响运动表现。兼顾营养充足与环境保护的食物选择，对于构建可持续膳食至关重要。 为此，本研究旨在评估低碳膳食满足青少年运动员蛋白质需求的充足性。 本研究采用横断面观察性研究设计，招募了来自里约热内卢体育俱乐部的91名青少年运动员，对其开展人体测量与食物摄入情况评估。为估算人类活动的环境影响，本研究采用碳足迹（carbon footprint, CF）与水足迹（water footprint, WF）作为可持续性评价指标。将运动员膳食的碳足迹与世界自然基金会（World Wildlife Fund, WWF）估算的1571克二氧化碳当量/人/天的基准值进行对比。本研究以美国营养与饮食学会（American Dietetic Association, ADA）针对运动员的蛋白质推荐摄入量，以及低碳EAT-柳叶刀参考膳食（EAT-Lancet reference diet）中的蛋白质食物组别作为参照依据。 研究按运动项目、年龄、性别与收入层级进行分层分析。采用GraphPad PRISM® 8.0版统计软件进行数据分析：先实施曼-惠特尼U检验，随后采用克鲁斯卡尔-沃利斯检验结合邓恩事后检验，以评估组间差异。 结果显示，碳足迹与水足迹与总能量摄入、总蛋白质摄入、动物源蛋白质摄入，以及肉类、蛋类食物组别呈正相关。基于运动组别与性别的膳食环境影响存在显著差异。环境影响较高的运动员群体特征为男性、中等收入阶层，且各年龄组均有分布。整体膳食的碳足迹四分位数均高于1571克二氧化碳当量/人/天的基准值。此外，即使在碳足迹最低四分位组的运动员中，多数也达到了美国营养与饮食学会推荐的每日蛋白质摄入量范围。由此可见，低环境影响的膳食可满足青少年运动员的蛋白质需求。 本研究结果对体育与食品行业具有参考价值，可为运动员平衡膳食的设计提供指导，同时有助于降低食品生产与消费过程中的负面环境影响。