Background: The first 1,000 days of life are a crucial period for supporting a child’s growth and development. Few studies have examined how food beliefs and taboos differ during this period based on the child’s nutritional status and cultural background. Objectives: This study aims to identify and compare food beliefs and taboos among mothers from four major ethnic groups in East Java (Madura, Arek, Mataraman, and Pendalungan), considering the nutritional status of their children (normal versus stunting) during pregnancy, lactation, and complementary feeding. Methods: A qualitative study was conducted using in-depth interviews with 144 mothers of children aged 6-23 months. Respondents were purposively selected based on children’s nutritional status (normal or stunted). Results: During pregnancy, most mothers across various ethnicities avoid “hot” foods, raw foods, sweet foods, and local ingredients such as kluwak, believing these foods can affect fetal health. During lactation, mothers of children with normal nutritional status generally avoid spicy foods, while mothers of stunted children avoid seafood, eggs, and herbal medicine. They believe these foods affect breast milk production. During complementary feeding, mothers of normal children avoid spicy foods and coconut milk, while mothers of stunted children also avoid ‘tape’ and Monosodium Glutamate (MSG), which are believed to cause digestive disorders. Conclusions: These findings highlight the importance of developing nutritional interventions that integrate local cultural practices. This program has the potential to improve stunting prevention programs and enhance maternal and child nutrition.