(RxWiki News) A wide range of public health campaigns have promoted healthier behaviors for teens. These include watching TV less, eating more fruits and vegetables and drinking less soda.
The good news, according to a recent study, is that these messages appear to be getting across.
TV watching and soft drink consumption are down while physical activity and fruit and vegetable consumption are up.
The less fortunate news is that teens' weights have not decreased alongside these changes.
However, their weights do appear to have stabilized, and there is a possibility they may begin to decrease.
"Practice weight-healthy behaviors."
The study, led by Ronald J. Iannotti, PhD, of the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Bethesda, Maryland, assessed changes in teens' weight and weight-related behaviors from 2001 to 2009.
The researchers compared three groups of nationally representative US students, grades 6 through 10, surveyed during that time period.
A total of 14,607 teens were surveyed in the 2001-2002 survey, 9,150 were surveyed in 2005-2006, and 10,848 were surveyed in 2009-2010.
The students answered questions related to how much physical activity they got, how much TV they watched, how much they used the computer or played video games, how many fruits and vegetables they ate, how often they ate breakfast and how many sweets or sweetened soft drinks they consumed.
The researchers found that positive behaviors modestly increased and behaviors linked to gaining weight modestly decreased during this time period.
The number of days each week that teens reported getting at least an hour of physical activity increased from an average 4.3 days in 2001-2002 to 4.5 days in 2009-2010.
The number of hours a day the teens watched TV decreased from an average 3.1 hours in 2001-2002 to 2.4 hours in 2009-2010.
There was no change in the amount of video game playing and computer use the teens reported during 2005-2006 and 2009-2010, the only two times the question was asked.
The number of days a week the teens ate fruits increased from an average 4.3 days in 2001-2002 to an average 4.9 days in 2009-2010.
The number of days a week the teens ate vegetables increased from an average 4.3 days in 2001-2002 to an average 4.6 days in 2009-2010.
The number of days out of the week the teens reported eating sweets decreased from 4.7 days in 2001-2002 to 4.1 days in 2009-2010.
The number of days out of the week the teens reported drinking sweetened soft drinks decreased from 4.9 days in 2001-2002 to 4.2 days in 2009-2010.
The number of weekdays the teens ate breakfast increased from 3 days in 2001-2002 to 3.3 days in 2009-2010.
All of these changes were small, but they were also mostly gradual changes headed in the right direction for behaviors linked to healthier weights.
At the same time, however, the teens' body mass index percentages increased. The body mass index (BMI) is a ratio of a person's height to weight used to determine how healthy a person's weight is.
The percentage of teens who had a normal BMI decreased from 70 percent in 2001-2002 to 66.6 percent in 2005-2006, where it remained in 2009-2010.
The percentage of overweight teens increased from 14.9 percent in 2001-2002 to 17 percent in 2005-2006 and then began to decrease slightly to 16.6 percent in 2009-2010.
The percentage of obese teens increased from 10.3 percent in 2001-2002 to 12.7 percent in 2005-2006, where it remained in 2009-2010.
It's not clear if the pattern of BMI changes has stabilized or is just beginning to turn around and start to gradually decrease.
It's also not clear, if there is a start to a decrease, whether this is due to the other changes in behaviors.
Continued research will be necessary to determine the long-term trends.
Eve Pearson, a licensed and registered dietitian at Nutriworks CNC in Dallas-Fort Worth, said this study's findings definitely present a bit of a mystery.
"It's definitely a large sample to pull from to be asking those questions, even though having the kids answer the questions is interesting because they don't recall things about nutrition very well," she noted about the way the study was conducted.
She also said it's clear that exercise definitely did not increase enough to make an impact if the teens decreased their caloric intake, though that information was not available.
Regardless, "the weights stabilizing is a great start even if it's not going down yet," Pearson said.
The study was published September 16 in the journal Pediatrics. The authors declared no conflicts of interest.
The research was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and by the Maternal and Child Health Bureau of the Health Resources and Services Administration.