Can a Baby Be Too Fat?

By Anna Davies
Contributing Writer

March 5, 2018

Why Are Babies So Fat?
It’s not as if baby has been hitting the drive-through in utero, so why are babies so fat when they’re born? Those adorable ankle, wrist and chin rolls are partly protective, experts say—the fat provides an energy source for baby as he adjusts to life outside the womb. And those chubby cheeks? They’re so large partially to help baby feed by supporting swallowing and sucking, explains Eboni Hollier, MD, a Houston-based pediatrician and assistant professor of pediatrics at Baylor College of Medicine.

Is a Fat Baby a Healthier Baby?
There’s a popular saying that fat babies are healthier babies—but that’s not necessarily true. A 5 pound newborn can be just as healthy as one who weighs 9 pounds. “A ‘fat’ baby at birth [who’s above the 90th percentile] is actually a greater indicator of the mother’s health than that of the baby’s,” says Rachel Lowdenback](, DO, a pediatrician practicing in Paducah, Kentucky. Maternal factors like gestational diabetes or excessive pregnancy weight gain may have contributed to baby’s large size, whereas moms with uncontrolled hypertension may have smaller babies. At the end of the day, baby’s birth weight is just one aspect of the newborn assessment, says Bande Virgil, MD, a pediatrician and creator of The Mommy Doc website. “A larger baby isn’t necessarily a healthier baby, and a smaller sized baby may not necessarily be unhealthy,” she says.

While it’s normal for any size baby to lose some of his birth weight, she should soon make up the difference. “Babies can lose up to 10 percent of their birth weight in their first week of life,” says Hollier. “However, most babies are back at their birth weight by the time they are 2 weeks old.” This is true regardless of how large baby was when born, so consult your pediatrician if baby continues to lose weight.

Is My Baby Too Fat?
“Wow, what does she eat?” “Look at that little linebacker!” “I could get lost in those chins!” Comments like these may make you question baby’s weight. Remember that newborns come in a range of sizes, depending on Mom’s genetic history and maternal health while baby was in utero—but regardless of baby’s size right out of the womb, he has a lot of growing to do. “Babies will double their birth weight by around 5 months of life and triple it by 12 months,” Hollier says.

According to the World Health Organization baby growth chart, by one month the “average” baby boy weighs 9.9 pounds and the average baby girl weighs 9.4 pounds, but deviations from this standard are perfectly normal. What’s more important, experts say, is that your newborn is following his or her own growth curve. “Instead of focusing on a particular number, parents should observe how much weight their child is gaining in regards to how much they are gaining in height as well,” notes Lowdenback. That means a baby who was born premature or is smaller at birth may have a lot of catch-up growth in the first few months after delivery. “In this case, their weight gain may seem excessive to parents,” says Lowdenback, “but if they’re catching up in height as well, then this gain is normal.”

That said, it is possible to overfeed a baby (although it’s rare). It’s more often seen among formula-fed babies, Virgil says, “especially if families are adding things like rice cereal to the formula, which increases the calories.” A parent’s desire to soothe baby can also sometimes lead to inadvertent overfeeding. It’s important to feed a newborn on demand, “but often parents mistake fussiness or restlessness for hunger,” Lowdenback says. “Instead of trying alternative soothing techniques, we’re quick to feed our child again. This can cause excessive weight gain.”

Baby’s birthweight isn’t predictive of her adult size, Hollier says. But a body of research that’s emerged over the years does point to a link between excessive weight gain in infancy (in relation to baby’s height) and risk of obesity later in life. “If overfeeding is the issue, then there is some evidence that this can prime fat cells early,” Virgil says. According to one study, published in 2016, babies who gained weight rapidly between birth and age one and a half were at three times the risk of being overweight or obese during the early school-age years.

If you’re ever concerned about baby’s weight gain, talk to your pediatrician, who can review your feeding schedule and offer pointers for keeping baby’s growth on track.