According to a study led by the University of Michigan which will be published in Pediatrics next month, becoming an older sibling before first grade may lower the risk of becoming obese. The study, which compared the body mass indexes (BMIs) of 697 children across the United States, found that the birth of a sibling between the ages of two and four was associated with a healthier BMI. Children without a sibling, meanwhile, were close to three times more likely to be obese by the first grade.
Researchers are not yet sure why the connection between younger siblings and weight exists. At the moment, they believe the birth of a second sibling may change the way parents feed their kids, or that having a sibling causes children to lead more active lives. Researchers believe that the simple presence of a younger sibling may motivate kids to spend less time involved in solitary, sedentary activities like television watching, and more time in so-called “active play.”
via Mental Floss
