<p>Metabolic and depressive disorders are major chronic global health concerns, often co-occurring and mutually reinforcing each other. Thus, understanding risk and protective factors underlying their development is crucial for identifying effective preventive strategies. Participants included N = 10,446 participants (31,418 observations) from the Adolescent Brain Cognitive Development Study aged 10-15 years. Primary outcomes were internalizing problem scores, and random slopes quantifying the within-person coupling between waist-to-height ratio and internalizing problems. Predictors included early-life adversity measures and potentially protective environments measured at the family, community, peer, and school level. Early-life adversity and protective environment scores were examined as moderators of the coupling between body composition and internalizing problems. Early-life adversity was significantly associated with the magnitude of within-person coupling (random slope); individuals with higher early-life adversity exhibited a stronger coupling between waist-to-height ratio and internalizing problems (r²=4.6%, t = 26.6, p &lt; 10⁻¹⁰). The adversity-related amplification of waist-to-height ratio and internalizing coupling was mitigated by the protective environment score (t = -5.3, p &lt; 10⁻⁶), with family and community components showing the strongest effects. Early-life adversity intensifies the coupling between waist-to-height ratio and internalizing problems, but protective environments may mitigate these effects. These findings motivate research into interventions that reduce early adversity and strengthen protective environments to improve youth mental and physical health.</p>