Having a Second Child Could Make Your Firstborn Healthier

According to recent research, having a second child might offer surprising health benefits to your firstborn. Would you have another for this reason?

Having a Second Child Could Make Your Firstborn Healthier

There may be one way to reduce your firstborn's risk of becoming obese—but it will require you to make a major life change. The upside? It just might be a change you've been thinking about making for other reasons.

A University of Michigan study suggests that becoming an older brother or sister might help keep your child's body mass index from creeping into the obese range. Researchers observed 697 children to reach this theory.

In the context of their study, children who did not have siblings were three times more likely to be obese by first grade. On the flip side, children who welcomed younger siblings when they were between two and four years old had the healthiest body weights.

The benefit of a younger sibling

"Research suggests that having younger siblings—compared with having older or no siblings—is associated with a lower risk of being overweight. However, we have very little information about how the birth of a sibling may shape obesity risk during childhood," Julie Lumeng, M.D., a developmental and behavioral pediatrician at U-M's C.S. Mott Children's Hospital and the study's senior author, said. "This study is believed to be the first to track subsequent increases in BMI after a child becomes a big brother or sister."

But while this theory is interesting, it begs the question: Why would something as seemingly irrelevant as having a younger sibling change a child's likelihood of gaining weight? According to the researchers, it might have something to do with the way parents raise their children after a new sibling is born. While there's no theory as to how feeding your older child is different than feeding a single or youngest child, it's worth considering that parents might subconsciously administer different food patterns when they have younger children to feed as well. Children build eating habits at around age three, so it's possible that parents change the way they feed their children once a second baby is in the picture, thus changing a child's long-term chance of becoming obese.

Researchers also suggest that children with siblings tend to have more active play time—if they're running around together, they're having less sedentary time. This can definitely help children maintain healthier weights.

The effect without a sibling

With that being said, you may be able to keep your child's chances of becoming obese to a minimum without having a second child. Implementing healthy eating habits early on and encouraging more active play time might do the trick even if you don't want to have another baby.

"We need to further study how having a sibling may impact even subtle changes such as mealtime behaviors and physical activity," Dr. Lumeng said. "Childhood obesity rates continue to be a great cause of concern. If the birth of a sibling changes behaviors within a family in ways that protect against obesity, these may be patterns other families can try to create in their own homes. Better understanding the potential connection between a sibling and weight may help health providers and families create new strategies for helping children grow up healthy."