There was an interesting study published in Science Advances in September of 2017, which seems to increase understanding about the womb and birth factors that can lead to obesity.

It’s long been known that certain womb conditions (such as diabetes or maternal obesity) are associated with obesity in the child. More recently, reports have also connected caesarean section birth with higher rates of obesity for people born using this procedure. It’s also known that certain abnormal profiles of colon bacteria are associated with obesity, so one group of researchers wondered if perhaps c-section babies were failing to pick up healthy bacteria that would be acquired from mother’s birth canal and perineum in a vaginal delivery.

These researchers studied a group of pregnant mice. In half the group, the researchers permitted normal vaginal delivery. In the other half, the researchers delivered the mice pups by c-section. Sure enough, at 15 weeks of age the group that was delivered by c-section was 15% heavier than the healthy-weight group born by vaginal delivery (the difference was highly statistically significant). The research group is planning next to experiment with oral inoculation of infants with some of Mom’s healthy bacteria shortly after birth.

This type of research strengthens the understanding that obesity is largely a disease of the modern environment, with many unexpected consequences of the wonderful technology that mostly helps us live longer and more enjoyable lives. There are certainly more factors to discover, but it’s clear that when obesity is predisposed from birth it not simply a matter of poor choices or willpower.