A one-year study of teenage girls and young women has found that alcohol consumption, above- average recreational Internet usage, and lack of sleep are all associated with increased weight gain.

Girls over 18 who slept less than five hours a night, ... who consumed two or more servings of alcohol a week and who spent large amounts of time on the Internet averaged about a four pound weight gain.

Weight gain in teens can cause a host of physical and social problems. The Harvard Medical School researchers studied over 5,000 girls and young women between the ages of 14 and 21. Each had their height and weight measured in 2000 and again in 2001. In 2001, they filled out surveys detailing their Internet use, sleep habits, alcohol and coffee consumption, and physical activity. The results show a correlation between alcohol consumption, above average recreational Internet usage and lessened sleep are all associated with weight gain. Girls over 18 who slept less than five hours a night on average, who consumed two or more servings of alcohol a week and who spent large amounts of time on the Internet averaged about a four pound weight gain over the course of the study.

The results of the study were published in the July issue of the Journal of Pediatrics. Weight gain was adjusted for increased height, physical activity, TV and video game use. All of these factors could themselves be responsible for changes in a teen's weight.

Even accounting for all these behaviors, subjects with the highest Internet usage were 57% more likely to have gained weight than their low usage counterparts. Only recreational Internet usage was considered, not usage for school or work.

Dr. Catherine Berkey, a biostatistician at Brigham and Women's Hospital and Harvard Medical School in Boston, headed the study. She suggests that parents encourage their adolescents to minimize the three behaviors that are associated with weight gain. "Four pounds may not seem like a big deal, but it's important to have weight stability in these years. One positive change will cause a cascade of positive changes."

The study was conducted only on females, but Dr. Madelyn Fernstrom, the director of the University of Pittsburgh Medical Center Weight Management Center, believes that the findings are likely applicable to teen males as well.

According to Dr. Fernstrom, the best way to keep matters from getting out of hand may be a proactive approach. If parents start setting limits on computer use and other potentially negative behaviors when their children are young, the children will be used to the idea of there being limits when they enter their teen years. This may sound difficult, but hey, no one ever said that being a parent was going to be easy.