Breastfeeding Protects Bigger Babies From Childhood Obesity—With One Exception

The effect lasts through age 6.
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ByAnisa Arsenault
Associate Editor
Mar 2018
close-up of mom breastfeeding newborn baby
Photo: Sony Khalizova

Among the many benefits of breastfeeding include faster postpartum weight loss for you and a healtheir, more stable body weight for baby. But what if your baby is big to begin with? New research confirms that healthy body weight effect applies to high-birthweight infants too.

At this weekend’s annual meeting of the Endocrine Society in Chicago, Hae Soon Kim, MD, of Ewha Womans University College of Medicine in Seoul, explained that in general, high-birthweight infants are more likely to be obese or overweight through age 6. The classification for high birthweight depends on at what week a baby was born, but in general, it exceeds the 8-pound, 13-ounce mark (4,000 grams), according to Children’s Hospital of Philadelphia. Kim says that the risk for becoming overweight or obese drops significantly for high-birthweight babies if they’re exclusively breastfed for their first six months.

To reach this conclusion, Kim and her study co-authors looked at data ranging from 2009 to 2016 from the National Health Information Database of Korea. It included information from pediatric health checkups of 38,039 children, which researchers split up into three groups: the low-birthweight group (less than or equal to 2,500 grams), the normal-birthweight group (over 2,500 grams and under 4,000 grams), and the high-birthweight group (4,000 grams or more). Over the years, about 10 percent of the low-birthweight infants and 15 percent of the normal-birthweight infants became overweight, compared to 25 percent of the high-birth weight infants. But this did not hold true if those high-birthweight infants were exclusively breastfed; in that case, their obesity risk went down.

“High birthweight is associated with overweight or obesity during early childhood. Among high-birthweight infants, exclusive breastfeeding is a significant protective factor against overweight and obesity,” Kim says in a recap of her findings.

Exclusive breastfeeding isn’t the only thing you need to do to prevent childhood obesity, however. According to additional findings presented at the Endocrine Society’s meeting, if a mother is overeating during breastfeeding, her child is at an increased risk for obesity. To keep that breastfeeding diet in check, check out our guide.

Q&A: Are Nuts Okay to Eat While Breastfeeding?

Jack Newman, MD, FRCPC