Your family’s dietary habits when you were a child may have more to do with your weight as an adult than your social interactions now, according to a new study from researchers at Newcastle University in the United Kingdom.
The study, which mainly focused on American siblings, found that genetics and a person’s upbringing help to form a child’s ideas about weight, instead of social networks formed later in life. This contradicts a previous study, which found weight gain was socially contagious.
Dr. Heather Brown and fellow researchers found other forces—like friends and society—had little immediate impact. In fact, social networks don’t influence obesity much later in life either. The study was published online at Obesity.
Data gleaned from the Panel Study of Income Dynamics allowed researchers to examine sibling body mass index data of siblings—nearly 240 living together and 838 living apart. They found genetic predisposition was far more important a predictor of body mass index than who you hang out with. Only amongst adolescent siblings still sharing a home were changeable factors like friendship, important.