The prevalence of child stunting in Indonesia is 30.8%, exceeding the figure required by WHO as much as 14% which has an impact on the country's gross domestic income. The main cause based on the behavioritic paradigm is the deviation of family behavior in the first 1000 Days of Life phase. The research method uses a mix-method, namely a qualitative method to map the factors that cause behavioural deviations and a quantitative method to examine the relationship between variables causing deviations. The sample is mothers who have to stunt children as many as 303 people. Data were collected by interview, FGD, and observation. Data analysis using chi-square test. Qualitative results show the taxonomy of causes of behavioural deviations including silence in communication between health workers, practical attitudes of families, orientation to modern lifestyles, hereditary experiences, and cultural perceptions. The quantitative results show that the mute variable of health workers has the most significant influence on the occurrence of behavioural deviations with a significance level of 0.028. The ability of health workers to assist families determines the occurrence of behavioural deviations that result in stunting in children. It is recommended to integrate the content of community empowerment into the health education.