Is baby bottle size a risk factor for obesity?

Could the size of the bottle you use to feed your baby contribute to obesity?

A new study shows that using a large formula bottle in early infancy contributed to greater weight gain and weight-for-length size, the American Academy of Pediatrics reports, indicating that formula bottle size alone may be a risk factor for obesity.

The study, "Bottle Size and Weight Gain in Formula-Fed Infants," which published online and will publish in the July 2016 Pediatrics, assessed 298 infants who were exclusively bottle-fed by the two-month pediatric visit and found that use of a larger bottle predicted .16 kg more weight gain and a larger weight-for-length size by the six-month appointment.

This finding supports the hypothesis that the mode of feeding (the bottle) is a more important factor in obesity than milk type, which has also been indicated by research showing infants fed only human milk by bottle gain more weight than breast-fed infants.

Researchers conclude that while these findings are important because it's known that infants fed primarily formula are heavier in infancy and at greater risk of obesity as they grow, more research is needed to more completely understand the link between bottle feeding and obesity risk.