AbstractObjectiveChina’s internal migration has left 61 million children living apart from their parent(s) in rural areas. The present study aimed to examine whether the relative contributions of macronutrients (protein, fat and carbohydrate) to total energy intake differ between children left behind by the father or mother, compared with children from intact families.DesignDrawing on a longitudinal study, the China Health and Nutrition Survey (1997–2009), multilevel modelling analyses (level 1: occasions; level 2: children; level 3: villages) were performed.SettingData from rural communities in nine provinces in China.SubjectsRural children (n975; 555 boys and 420 girls) from 140 villages.ResultsAmong boys of school age, being left behind by the father tended to reduce the relative protein intake by 0·70 % (P<0·01) compared with boys from intact families. Being left behind by at least the mother was more detrimental for young boys under the age of 6 years than paternal migration, reducing relative protein intake by 1·14 % (P<0·05). Parental migration was associated with a significant increase in young boys’ relative fat intake by 2·60 % (P<0·05). No significant associations were found for girls. Results suggest left-behind boys, especially in early life, are subject to a higher-fat and lower-protein diet compared with non-left-behind boys. This may put them at increased risk of being overweight or obese, or of suffering from stunted growth, when they grow up.ConclusionsPublic health policies should recognise the influences of parental migration on boys, especially maternal migration, and encourage a more balanced diet for children in rural China.