Parents, take note! Becoming a big brother or big sister before first grade may lower a child's risk of becoming obese, a new study suggests.
The birth of a sibling, especially when the child was between about 2 and 4 years old, was associated with a healthier body mass index (BMI) by first grade, according to the research.
Children the same age who did not have a sibling were nearly three times more likely to be obese by first grade.
"Research suggests that having younger siblings - compared with having older or no siblings - is associated with a lower risk of being overweight," said Julie Lumeng from University of Michigan in the US.
"However, we have very little information about how the birth of a sibling may shape obesity risk during childhood," Lumeng said.
One possible explanation, researchers speculate, could be that parents may change the way they feed their child once a new sibling is born.
With children developing long-lasting eating habits at around three years old, changing dietary habits may have a significant impact.
This study is believed to be the first to track subsequent increases in BMI after a child becomes a big brother or sister.
Researchers also note that children may engage in more "active play" or less sedentary time in front of screens once a younger sibling is born, contributing to healthier BMIs.
The findings were published in the journal Pediatrics.
