Mapping 35 years of medical specialty theses on clinical nutrition in Türkiye: the rise of the muscle-focused paradigm.

OBJECTIVE: The aim of this study was to analyze the thematic and methodological evolution, alignment with global literature, and publication conversion rates of medical specialty theses in clinical nutrition in Turkey between 1990 and 2025. METHODS: A total of 750 theses were retrospectively analyzed from the Turkish National Thesis Center database. Data were evaluated for thematic content, diagnostic tools, and interdisciplinary distribution using Callon's centrality/density metrics and segmented regression models. RESULTS: The dominant research themes were sarcopenia and muscle health (36.5%), nutritional support (28.0%), and malnutrition scores (26.4%). A strong thematic association was found between sarcopenia and frailty, primarily concentrated in geriatrics. Geriatrics exhibited the highest statistical density for sarcopenia and frailty themes (Adjusted Residual: +6.1). Objective muscle measurements were included in 48.2% of theses, with 65% of these utilizing computed tomography-based "opportunistic imaging." Segmented regression identified 2015 as a significant structural breakpoint in thesis production (p<0.001). The overall publication rate was 28.4%, with the highest conversion observed in sarcopenia-focused theses (42.0%; 95%CI 36.2-47.8). Conversely, cachexia was the least represented area (1.2%). CONCLUSION: Clinical nutrition research in Türkiye has evolved into a muscle-focused, phenotype-based paradigm, with geriatrics serving as the primary driver. While sarcopenia has become central to clinical research, complex wasting syndromes like cachexia remain academically neglected. These findings demonstrate that geriatric nutrition plays a decisive role in national academic output, though more holistic and multidisciplinary research strategies are needed for future academic training.