BACKGROUND: Dietary lipids, sedentary habits, and eating behaviors influence childhood obesity, but their interrelations remain unclear. AIM: To assess the relationships between young children's dietary lipid profile and children's eating behavior, as well as their sedentary habits, providing evidence-based insights that can help mitigate obesity risk in this vulnerable population. DESIGN: A longitudinal randomized controlled trial conducted over 9 months, involving 90 children aged 2-6 years with overweight or obesity who were followed under a program that promoted healthy lifestyle habits for all participants and regularly monitored their parameters. METHODS: The dietary lipid profile, eating behavior, and sedentary habits were assessed at baseline and after 9 months using validated tools, including 24 h recalls, the child eating behavior questionnaire (CEBQ), and screen time questionnaires. RESULTS: Reductions in screen/sedentary time were significantly associated with decreased total fat (-11.1 g/day) and saturated fat (-4.3 g/day) intake, compared to smaller reductions in unchanged screen hours and increases with prolonged screen use. A positive correlation was observed between changes in dietary fat and the CEBQ domain "Desire to drink" (r = 0.528, CONCLUSIONS: Managing screen time and eating behavior is crucial for improving dietary lipid profile and reducing childhood obesity risk. Strategies should include reducing sedentary behaviors, limiting sugary drinks, and promoting water as the main beverage, alongside effective nutrition education for families.