Background <p>This study examined the associations between circulating lipid subfractions and long-term adiposity progression, and identified biomarkers reflecting baseline obesity status and future adiposity change.</p> Methods <p>This study included 1502 participants from the China Kadoorie Biobank who had available nuclear magnetic resonance data at baseline and completed anthropometric measurements at both the baseline survey and the second resurvey. Excessive adiposity increase was defined as a body mass index (BMI) increase of ≥5% from baseline. Modified Poisson regression models were used to estimate relative risk (RR) per standard deviation (SD) higher lipid trait.</p> Results <p>During a median follow-up of 8 years, 33.3% of participants experienced ≥5% increase in BMI. High baseline cholesterol percentages in most low-density (LDL) and high-density lipoprotein (HDL) subclasses were associated with elevated risks of excess adiposity increase (RRs per SD: 1.09–1.18), with subclass-specific patterns observed across cholesterol forms. Conversely, triglyceride (TG) enrichment in most lipoprotein particles was inversely associated with adiposity progression (RRs per SD: 0.90–0.80), except for larger very low-density lipoprotein particles. Notably, most TG-enriched subfractions were associated with baseline obesity status but inversely associated with longitudinal adiposity progression. In contrast, cholesterol enrichment in HDL and LDL subclasses was associated with long-term adiposity increases, yet inversely associated with baseline adiposity.</p> Conclusions <p>Cholesterol-enriched lipoproteins, particularly in medium-to-small subclasses, may contribute to long-term obesity progression risk, while elevated TG subfractions primarily reflect current obesity status.</p> <p></p>