Sure, siblings may fight all day and never let you get a moment of peace, but now there's another benefit for kids that grow up with younger brothers and sisters: a lowered risk of obesity in the future. After following 697 children in the U.S., researchers discovered that those who didn't have any younger siblings by first grade were three times more likely to be obese.
According to a new study out of the University of Michigan, "Research suggests that having younger siblings—compared with having older or no siblings—is associated with a lower risk of being overweight." It's supposedly the first study to ever track increases in children's body max indexes (BMI) after the birth of a younger brother or sister.
While researchers admit they don't know exactly what causes the significant gap in obesity risk, they do have some theories. One is that the older child may simply lead a more active, less screen-filled lifestyle once their sibling is born as they always have a built-in playmate. According to lead researcher Dr. Julie Lumeng, "Maybe families are more likely to take the kids to the park when there is a younger sibling, or maybe the child is less likely to be sedentary, watching TV, when there is a younger sibling to engage them in more active pretend play."
Another theory speculates that perhaps parents begin to change feeding styles once a second child enters the family. With just one child, lots of parents are hyper vigilant about what they do and don't eat and, let's face it, just more obsessed in general because they have more time. But once the second child is here, many parent tend to loosen up on on restrictions, either by choice or just because there's no more time to obsess anymore.
One of the researchers, Jerica Berge, notes "When parents use restrictive (e.g., keep food from children) or pressure-to-eat feeding practices (e.g., try to get kids to eat more food), children have an increased risk of being overweight," so this more relaxed way of feeding may prove to be beneficial in the long run.
And the magic time to have that second child to achieve maximum health benefits? Apparently it's when your oldest child is between two and four years old. Those that experienced the birth of a sibling between those ages were linked to have a lower BMI by the time they turned six.
The study concludes that "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."