Family, friends, social ties influence weight status in young adults

Does obesity tend to 'cluster' among young adults? And if so, what impact does it have on both their weight and weight-related behaviours? That's what researchers from The Miriam Hospital's Weight Control and Diabetes Research Centre set out to answer to better understand how social influences affect both weight status and weight loss intentions in this difficult-to-reach age group.

According to the study, published online by the journal Obesity, overweight and obese young adults between the ages of 18 and 25 were more likely to have overweight romantic partners and best friends and also had more overweight casual friends and family members compared to normal weight peers. Also, overweight and obese young adults who reported having social contacts trying to lose weight had greater weight loss intentions.

Why is this an important issue? Forty percent of young adults age 18-25 are considered overweight or obese, and young adults experience the highest rate of weight gain per year - typically one to two pounds - of any age group. While previous research has consistently demonstrated the powerful impact of social influence on health behaviours, especially for younger individuals, no previous study has examined whether social ties influence weight status and weight loss intentions among young adults.

Lead author Tricia Leahey, PhD, a researcher with The Miriam Hospital's Weight Control and Diabetes Research Centre, also points out that young adults are less likely to participate in behavioural weight loss interventions, and when they do, they tend to lose less weight than older adults. 'Identifying the factors that influence both weight status and weight control in this high-risk age group can help us develop appealing and effective obesity treatment and prevention programs for this population,' she said.

The study included 288 young adults between the ages of 18 and 25; 151 individuals were of normal weight, while 137 were considered overweight or obese (BMI of 25 or greater). The majority of participants were female and Caucasian. All participants completed questionnaires to determine their weight and height, number of overweight social contacts (including best friends, romantic partners, casual friends, relatives and colleagues/classmates) and perceived social norms for obesity and obesity-related behaviours.

Overweight and obese study participants completed additional questionnaires to assess how many of their overweight social contacts were currently trying to lose weight, perceived social norms for weight loss (such as how frequently social contacts encouraged them to lose weight or whether the people closest to them would approve if they were to lose weight), and intentions to lose weight within the next three months.

Compared to normal weight young adults, those who were overweight or obese were more likely to have an overweight romantic partner (25 percent vs. 14 percent) and an overweight best friend (24 percent vs. 14 percent). 'Our data suggests that obesity 'clusters' in this population. But interestingly, social norms for obesity did not differ between the two groups and did not account for the clustering,' said Leahey. 'Both groups reported similarly low levels of social acceptability for being overweight, eating unhealthy foods and being inactive.'

The study also showed overweight and obese young adults who had more social contacts trying to lose weight were more likely to want to lose weight themselves. Social norms for weight loss, such as encouragement and approval from social contacts, account for this association, researchers say.