This paper aims to analyze the thin subsidies effect on nutritional status and individual food acquisition for individuals in poverty between 2 and 9 years old. With the data of a Brazilian family budget survey, I estimated a model that identifies the individual consumption of calories, based on aggregate household consumption, followed by the estimation of a child health production function, which verifies the effect of a set of variables on Body Mass Index (BMI). Finally, I estimated the children's food demand system for various food categories (healthy and unhealthy). I found that the implementation of thin subsidies can be effective for the variability of healthy food destined to children, contributing significantly to the joint increase in food consumption that reduced prices (fruits, vegetables, fish and milk). However, only the variation in the amount of fruit suffers a variation that is more than proportional to the 20% variation in the price of the selected basket. The discount increases unhealthy food consumption (ultraprocessed and soft drinks) due to the complementarity relationship. Thereby, the combined discount granted to a healthy food basket increases the average total caloric intake. This intervention does not reverse the process of average BMI growth of economically vulnerable children and, consequently, it could not reduce the incidence of childhood obesity. In general, the analysis proposed was essential to understand how specific policy interventions can encourage healthy habits, giving attention to their impacts on vulnerable individuals. Children nutritional status. Children food demand system. Thin subsidies.