To evaluate the association between weight status and food insecurity of children living in social vulnerability who are beneficiaries of a food assistance programme (FAP).

Cross-sectional study.

From all children benefiting from the FAP in the municipality, 30 % were mapped in forty-seven distribution points. Their weight status was evaluated using BMI-for-age and food insecurity was determined with the Brazilian Food Insecurity Scale. Socio-economic data of the participants were collected using regular questionnaires. The main outcome measure was obesity.

To be a beneficiary of the FAP, a family must have a child aged 24–96 months and receive less than half a minimum wage per capita. Participating families receive 1 litre of whole milk per day.

In all, 1487 children had BMI-for-age and food insecurity data. Of these children, 376 (25·3 %) had excess weight, of whom 164 (11·0 %) presented with obesity, and only twenty-seven (1·8 %) were underweight; 76 % of the families had some degree of food insecurity. Multivariable analysis revealed no overall association between household food insecurity and weight status. In the specific comparison, children living in severe food insecurity were less likely to present obesity than those children living in food security (prevalence ratio = 0·60; 95 % CI 0·38, 0·96; P = 0·03).

In a socially vulnerable population that participates in a FAP, there was no overall association between food insecurity and weight status in children, a result which is similar to what is observed in more developed contexts.