The types of food introduced during complementary feeding and risk of childhood obesity: a systematic review.

The determinants of childhood overweight and obesity are complex, but infant feeding and the early diet are important contributing factors. The complementary feeding period in particular, is a time during which children are nutritionally vulnerable, and a time where life-long eating habits may be established. We conducted a systematic review of the literature that investigated the relationship between the types of food consumed by infants during the complementary feeding period and overweight or obesity during childhood. Electronic databases were searched from inception until June 2012 using specified keywords. Following the application of strict inclusion/exclusion criteria, 10 studies were identified and reviewed by two independent reviewers. Data were extracted and aspects of quality were assessed using an adapted Newcastle-Ottawa scale. Studies were categorised into three groups: macronutrient intake, food type/group and adherence to dietary guidelines. Some association was found between high protein intakes at 2-12 months of age and higher body mass index (BMI) or body fatness in childhood, but was not the case in all studies. Higher energy intake during complementary feeding was associated with higher BMI in childhood. Adherence to dietary guidelines during weaning was associated with a higher lean mass, but consuming specific foods or food groups made no difference to children's BMI. We concluded that high intakes of energy and protein, particularly dairy protein, in infancy could be associated with an increase in BMI and body fatness, but further research is needed to establish the nature of the relationship. Adherence to dietary guidelines during weaning is recommended.