<p>This study investigates the dual burden of malnutrition in China, characterized by the simultaneous presence of both undernutrition and overnutrition, through the lens of health sociology and opportunity inequality. It delves into the disparities in health outcomes across different life stages and the intergenerational mechanisms. Leveraging data from the China Health and Nutrition Survey (CHNS), the study applies both pre- and post-outcome methods to quantitatively assess opportunity inequality. The findings reveal a notable decline in the prevalence of stunted growth and underweight among children over time, juxtaposed with a persistent rise in overweight and dual malnutrition rates. Among adults, opportunity inequality linked to undernutrition and overnutrition intensifies significantly with advancing age. Environmental factors emerge as the dominant contributors, accounting for over 80% of the inequality, while effort-related factors exert a marginal impact, largely confined to extreme cases. The research also uncovers the intergenerational perpetuation of opportunity inequality, compounded by regional disparities in economic and social resources. These findings highlight the pressing need for a dual approach combining environmental enhancements with targeted interventions to address health inequalities, offering vital policy insights for advancing the Healthy China strategy.</p>