Five-Year Trends in Dietary Intake by Gender Among Korean Preschoolers (2017–2021): Nationwide Survey-Based Surveillance Amid Rising Demand for Medical Care for Precocious Puberty

Background/Objectives: Care-seeking for precocious puberty (PP) in South Korea has risen sharply, coinciding with dietary westernization among children. This study describes sex-specific and temporal dietary trends among Korean children aged 1–11 years, focusing on the 6–11-year band preceding the typical PP diagnosis threshold. Methods: Using KNHANES (2017–2021) dietary data and HIRA care-seeking counts with the sex-year aggregate, not the individual child. Sex differences were assessed using the Mann–Whitney U test, year-to-year patterns using a sex-by-year interaction model (n = 5 annual observations per sex), and dietary pattern structure using principal component analysis (PCA) on 12 food groups (n = 10 sex-year observations). Results: PP care-seeking rates rose in both sexes, substantially more in girls. Boys showed significantly higher intake of most food groups and macronutrients; within the 6–11-year band this held for meat, cola, and macronutrients (p = 0.008) but not legumes (p = 0.421). Macronutrient sex gaps numerically narrowed while meat and cola gaps widened over 2017–2021, though none reached significance. PCA identified a primary axis reflecting overall intake volume that separated boys and girls, and a secondary axis distinguishing a dairy/seaweed/beverage profile from a meat/egg/cola-dominant profile. Conclusions.: These findings describe sex-specific dietary patterns amid rising PP rates without establishing that intake volume explains the sex disparity, identifying candidate exposures for future research and cautioning against oversimplified dietary narratives.