Teen Weight Levels Off, Habits Improve

September 16, 2013

News Review From Harvard Medical School -- Teen Weight Levels Off, Habits Improve

Teens have improved some of their health habits, and excess weight has leveled off, the latest national survey suggests. The study was based on national surveys of kids in grades 6 through 10. The survey is conducted every 4 years. The first of 3 surveys began in 2001. The last one ended in 2010. In all, 34,000 teens were involved. They were asked their weight, height and questions about diet, exercise and screen time. Between the second and third surveys, the obesity rate leveled off and the rate of overweight teens dropped a bit. Teens reported eating more fruits and vegetables and fewer sweets. They also reported having fewer sweetened drinks. They ate breakfast on weekdays more often. They were more active and spent less time watching TV. However, video game and computer use went up a bit. The improvements were small. And researchers said there's a long way to go. Most teens are not meeting the goal of an hour of exercise per day, for example. The journal Pediatrics published the study. HealthDay News wrote about it September 16.

By Henry H. Bernstein, D.O.
Harvard Medical School
 

What Is the Doctor's Reaction?

Being obese means having too much body fat for a specific body type. You cannot tell just by looking at someone. Body mass index (BMI) is the best way to know. The formula for BMI uses how tall people are along with how much they weigh.

Based on age and gender, a child with a BMI:

• Less than the 5th percentile for all children is "underweight"
• Between the 5th and 84th percentiles is normal
• At or above the 85th percentile is "overweight"
• At or above the 95th percentile is "obese"

The journal Pediatrics has just released a study online about overweight and obese teenagers. Researchers surveyed thousands of teens and preteens, (ages 11 through 16) all over the United States. The questions related to their weight, height and behaviors. The surveys were completed every 4 years between 2001 and 2009.

The researchers looked at trends in behaviors that may be related to obesity. They focused on:

• Physical activity
• Screen time (watching TV, playing video games and using the computer)
• Diet

Overall, healthy behavior improved. By the end of the survey years, U.S. teens:

• Exercised more
• Watched less TV
• Ate more fruits and vegetables
• Ate fewer sweets
• Drank less soda
• Ate breakfast more often

The researchers matched these trends with the teens' BMI percentile group (underweight, normal weight, overweight or obese).

• Between 2001 and 2005, both overweight and obesity rates went up.
• Between 2006 and 2010, these rates stayed about the same.

There were some differences noted by sex, age and race/ethnicity. For example:

• BMI percentiles were higher in boys than in girls.
• Boys reported more physical activity, but more screen time.
• Girls reported eating more fruits and vegetables, but also more sweets.
• Compared with younger teens, older ones:
  • Were less active
  • Ate less healthy foods
  • Had higher BMI percentiles
• Compared with white teens, African-American and Hispanic ones
  • Were less active
  • Ate less healthy foods
  • Had higher BMI percentiles

This study seems to show that public health efforts may be working. These overall healthier behaviors by teens might explain why obesity rates seem to have leveled off.

The researchers say this is not enough. By 2009, the average teen still did not get enough exercise, watched too much TV and ate too much unhealthy food. Teens need to keep improving their behaviors. Then obesity rates might really go down.

What Changes Can I Make Now?

Is your child overweight or obese? Ask the doctor to check his BMI. The doctor then can suggest next steps. She can work together with your family. She can also suggest resources in your community for healthy eating, physical activity and losing weight. 

Remember, YOU are a role model. Your child is more likely to exercise and eat healthy foods if you do. You will be healthier, too! Here are some things your whole family can do:

Get moving.

• Try to do something active for at least one hour every day.
• Walk whenever possible: to school, to the store, to the library, at the mall and around the block after dinner.
• Take the stairs instead of the elevator.
• Plan family activities with exercise, such as biking, dancing, hiking or swimming.
• Limit television, computer and video-game time to two hours or less per day.

Eat healthy foods.

• Cook and eat meals together as a family.
• Limit fast food, take-out food and how often you eat out at restaurants.
• Never watch television while eating.
• Teach your child not to skip meals, especially breakfast. We tend to eat more at the next meal.
• Try to eat at least five servings of fruits and vegetables every day.
• Eat low-fat dairy products, such as yogurt, milk and cheese.
• Limit foods with lots of fat or sugar, such as pizza, fatty meats, cakes, cookies and candy.
• Drink fewer sugar-sweetened drinks, such as soda and juices. Encourage water and low-fat milk instead.

What Can I Expect Looking to the Future? 

Expect to hear more about your teen's BMI at yearly checkups. The doctor will give advice on the value of a healthy diet. The doctor also will encourage more physical activity.

I hope that following this advice will mean a decrease in the number of teens who are overweight or obese. We want to help children avoid these serious health problems later in life:

• High blood pressure
• High cholesterol
• Heart disease
• Type 2 diabetes
• Arthritis