Objective <p>This study aims to investigate the association between adherence to the EAT-Lancet diet and the prevalence of sarcopenia as well as sarcopenic obesity in adults.</p> Methods <p>This study included 9672 participants from the National Health and Nutrition Examination Survey. We developed an EAT-Lancet score based on 24-hour dietary recall data and grouped the participants according to the quartiles of this score. Weighted multivariate logistic regression models and restricted cubic splines were employed to assess the association between the EAT-Lancet diet and sarcopenia and sarcopenic obesity. Additionally, mediation analysis was conducted to evaluate the mediating role of inflammatory biomarkers in this relationship.</p> Results <p>Among the 9672 participants, 910 (9.41%) were identified with sarcopenia, and 607 (6.28%) were identified with sarcopenic obesity. After adjusting for potential confounders, the odds ratios (OR) and 95% confidence intervals (CI) for sarcopenia and sarcopenic obesity in the highest quartile groups were 0.72 (0.54–0.95) and 0.58 (0.42–0.82), respectively, compared to those in the lowest quartile group. A 10-point increase in the EAT-Lancet diet score was significantly associated with a reduced risk of sarcopenia and sarcopenic obesity, with OR (95% CI) of 0.90 (0.84–0.98) and 0.86 (0.79–0.93), respectively. Furthermore, white blood cell count demonstrated the strongest mediating effect on this association, followed by C-reactive protein, systemic inflammation response index and systemic inflammatory index.</p> Conclusion <p>Our study indicated that adherence to the EAT-Lancet diet was associated with a lower risk of sarcopenia and sarcopenic obesity, with this association partially mediated by inflammatory biomarkers.</p>