Associations Between 24-h Movement Behaviors and Macronutrient Intake Among Students Aged 6–17 Years: Insights from the China Health and Nutrition Survey

<b>Background/Objectives:</b> This study aims to examine the relationships between 24-h movement guideline (24HMG) adherence and macronutrient intake, as well as assess dose-response relationships between 24-h movement behaviors and macronutrient intake among students aged 6-17 years. <b>Methods:</b> The study included 3624 participants aged 6 to 17 years from four rounds (2004-2011) of the Chinese Health and Nutrition Survey (CHNS). Participants' 24-h movement behaviors and dietary intakes were evaluated. <b>Results:</b> Adherents to physical activity (PA) guideline had higher carbohydrate, fat, and protein intake (all <i>p</i> < 0.05). Those following the screen time (ST) guideline had a higher percentage of dietary energy intake (E%) from carbohydrates but a lower percentage from fat (all <i>p</i> < 0.05). Sleep (SLP) guideline adherents demonstrated lower protein intake and E% (all <i>p</i> < 0.05). PA guideline adherents were less likely to exceed carbohydrate Dietary Reference Intakes (DRIs) (OR = 0.83, 95% CI: 0.69-0.99), but more likely to surpass fat DRIs (OR = 1.20, 95% CI: 1.02-1.40). ST guideline adherents were more likely to exceed carbohydrate DRIs (OR = 1.32, 95% CI: 1.11-1.56) and less likely to surpass fat DRIs (OR = 0.78, 95% CI: 0.68-0.91). Dose-response analyses showed that moderate-to-vigorous physical activity (MVPA) and ST had positive linear associations with carbohydrate intake below DRIs. ST also showed positive linear associations with fat intake above DRIs. MVPA showed a nonlinear relationship with fat intake above DRIs. <b>Conclusions:</b> Among Chinese children and adolescents aged 6-17 years, those who meet the PA guideline should be cautious about the risk of excessive fat intake, while those adhering to the ST guideline should be aware of the risk of excessive carbohydrate intake in their daily diet. For promoting health and maintaining balanced macronutrient intake, MVPA should range from 60 to 90 min per day. This study underscores the importance of adjusting macronutrient intake according to levels of 24-h movement behaviors, especially MVPA and ST.