Guess what, having a younger sibling lowers obesity risk

Birth of a younger sibling makes a child engage in more 'active play', helping in maintaining a healthy BMI.

Becoming an elder brother or sister before pre-school days can lower a child’s risk of becoming obese, researchers suggest. They added that children who didn’t have a sibling are three times more likely to become obese by the first grade.
The birth of a sibling by the time a child reaches the first grade — or when the child is 2-4-years-old — can help the kid maintain a healthier body mass index (BMI). “Having younger siblings — compared with having older or no siblings — is associated with a lower risk of being overweight,” said senior author Julie Lumeng, paediatrician at University Of Michigan.
However, how the birth of a sibling can shape risk of obesity during childhood is unclear yet.