This study is a secondary data analysis that examines the association between parent modelling of dietary intake and physical activity and the same child behaviours among different races/ethnicities using innovative, rigorous and objective measures.

Ecological momentary assessment surveys were sent to parents to assess whether their child had seen them exercise or consume food. Dietary recall data and accelerometry were used to determine dietary intake and physical activity behaviours of children.

Participants were randomly selected from primary care clinics, serving low-income and racially/ethnically diverse families in Minnesota, USA.

Participants were families with children aged 5–7 years old who lived with parents 50 % of the time and shared at least one meal together.

A 10 percentage point higher prevalence in parent modelling of fruit and vegetable intake was associated with 0·12 higher serving intake of those same foods in children. The prevalence of parent modelling of eating energy dense foods (10 % prevalence units) was associated with 0·09 higher serving intake of sugar-sweetened beverages. Furthermore, accelerometry-measured parent sedentary hours was strongly correlated with child sedentary time (0·37 child sedentary hours per parent sedentary hours). An exploratory interaction analysis did not reveal any statistical evidence that these relationships depended on the child’s race/ethnic background.

Interventions that increase parent modelling of healthy eating and minimise modelling of energy dense foods may have favourable effects on child dietary quality. Additionally, future research is needed to clarify the associations of parent modelling of physical activity and children’s physical activity levels.