Approximately one in five children aged 5–17 years are overweight or obese, and by 2025, 80 million infants and young children from low- and middle-income countries will be overweight or obese. In this presentation, Dr Dattilo described modifiable, and potentially modifiable, factors during pregnancy, after birth and during complementary feeding that are associated with childhood overweight and obesity. Recent evidence indicates that the genesis of childhood obesity may be rooted in the period between conception to 2 years of age, in which nutritional-, metabolic- and diet-related behavioural ‘programming’ may be established. Studies have shown that breastfeeding is associated with moderate, but consistent, protective effect against obesity in later years. There is some evidence on the associations of complementary feeding with early infancy weight gain and obesity, and these include studies on early or late solid food introduction, sugar sweetened beverage intake, prolonged bottle use, protein intake and overall dietary score.