US college girls: Fatter roomie helps control 1st-year plumpening

In a groundbreaking study, American researchers reveal that all US college girls tend to find their clothes fitting tighter in their first year as they gain weight. However, in a shock finding, it seems that those who are assigned a plump roommate will embulgen themselves less than those who find themselves living with a skinny.

The college argot phrase "freshman 15" is used in the States to describe the extra wobble acquired by undergraduates in their first year as they quaff booze, scoff tuck from all-you-can-eat dining halls and cease the often compulsory exercise insisted on by high schools.

According to a new study on female first-years (still called "freshmen" in the States) at the University of Michigan, however, the waistbands and zippers of America's youth aren't put under quite such severe strain as the term suggests. Rather than a skirt-splitting 15 pounds, the girls in the study put on 2.5 pounds if they had a "slim" roommate, and just half a pound if they were paired up with a porker.

"This finding seems counterintuitive, but there are some good explanations for why it may be happening," said Kandice Kapinos, a sociologist involved in the study.

"It's not really the weight of your roommate that's important, but the behaviors your roommate engages in. These behaviors are what may really be 'contagious.'"

Rather than swilling lager, gorging on chocs and the leaving of top buttons undone, the behaviours Kapinos refers to are such ones as dieting and going to the gym. Overweight roommates are likelier to do such things, thus encouraging freshers into healthier habits.

Kapinos and her colleague Olga Yakusheva, collaborating on the young-girl plumpening study, say that it flies in the face of established wisdom which states that mixing with fatties tends to make you fatter. But apparently this ignores the crucial factor of randomness.

"Previous studies have suggested that having an obese spouse, friend or sibling increases one's likelihood of becoming obese," Kapinos said. "But these relationships are obviously not random. People pick their friends and spouses, and they often select people who are similar to themselves. And even though we don't pick our siblings, we share a genetic inheritance and an early environment that may influence adult weight."

The two social scientists consider that their research may be important against the background of a US youth population whose buttons are apparently pinging off their clothes left and right. According to this statement on the study, issued yesterday by Michigan uni:

The topic of peer influences on weight gain and weight management is important since obesity prevalence in young adults, aged 18 to 29, increased by 96 percent from 1988 to 2006—the largest percentage increase for all age groups.

These figures, however, are based on the widely-discredited Body Mass Index (BMI) system, which is based on the idea that human bodies are two-dimensional rather than three-dimensional, producing some bizarre results (professional athletes' BMI has climbed massively as they have become fitter and more muscular, for instance). Recent studies have suggested that an "overweight" BMI should probably now be taken as "normal" in terms of health consequences, and even an "obese" BMI has no health downside for the under-40s. ®