Objective: Few studies are focused on sugar consumption around the first 1000 d of life. Thus, this work modelled the pathways linking the consumption of sugary drinks in pregnancy and maternal pre-gestational BMI to early child’s exposure to products with high sugar content and to BMI z-score in the second year of life. Design: BRISA cohort, São Luís, Brazil was used from the baseline to the follow-up at the second year of life. Setting: A theoretical model was constructed to analyse associations between variables from prenatal period (socio-economic status, age, frequency of sugary drinks consumption during pregnancy and pre-gestational BMI), birth weight, exclusive breast-feeding and two outcomes: higher calories from products with added sugar as a percentage of the total daily energy intake and BMI z-score at follow-up at the first 2 years of life, using structural equation modelling. Participants: Data of pregnant women (n 1136) and their offspring. Results: Higher pre-gestational BMI (standardised coefficient (SC) = 0·100; P = 0·008) and higher frequency of sugary drinks consumption during pregnancy (SC = 0·134; P < 0·001) resulted in high percentage of daily calories from products with added sugar in the second year of child, although no yet effect was observed on offspring weight at that time. Conclusions: Maternal obesity and sugary drinks consumption in pregnancy increased the risk of early exposure (before to 2 years) and high exposure of child to added sugar, showing perpetuation of the unhealthy dietary behaviours in the first 1000 d of life.