The Ideal Weight For A Teen Girl

The ideal weight for a teen girl is based on several factors, but always comes back to one answer: healthy. Your teen daughter’s Body Mass Index, or BMI, will help to determine whether she is at a healthy weight for her height and age. Unlike adult BMI, which is constant and static, healthy BMI for children and teenagers varies because their bodies are not yet fully developed; one teen girl with a BMI of 20 may be considered healthy weight, while another teen girl with a BMI of 20 may be considered overweight.

Changing Bodies

Teen girls are constantly developing and constantly changing. Visibly, they grow taller, develop breasts and may develop fuller hips. Internally, a teen girl’s bone composition, body fat content and body fat distribution will change, as well. These continuous bodily changes make it impossible to pinpoint one healthy BMI number or BMI range of numbers. As a result, once you or your daughter have calculated her BMI, you need to plot it against a BMI percentile chart to determine whether that BMI is healthy.

Calculating BMI

Calculating BMI is a simple mathematical process. Divide your weight in pounds by your height in inches, then divide that number by your height in inches again. Multiply that number by 703 to find your BMI. For instance, if your teen daughter weighs 130 pounds and is 5’6”, you would divide 130 by 66, getting 1.969, then divide 1.969 again by 66 to get .0298. You would then multiply .0298 by 703 to get a BMI of 20.98. There is a link in the resources for the Centers for Disease Control's free online child and teen BMI calculator.

BMI Percentile

Once you know your BMI number, you will be able to plot it according to its percentile range. Where your BMI number falls on the graph will determine whether your teen girl’s BMI is healthy. If your teen daughter’s weight falls between the 5th and 85th percentiles, her weight is considered healthy. If it falls between the 85th and 95th percentiles, she is considered overweight; above the 95th percentile is obese. Conversely, if your daughter’s weight is under the 5th percentile, she is considered underweight. See the Resources for a link to a copy of the CDC’s BMI-for-age percentiles for girls.

Body Image

When discussing ideal weight with your teen daughter, you should also reinforce with her a positive body image. Weight problems and fad diets occur when girls--boys, too!--set unrealistic expectations for their image and shape. Help your daughter recognize that there is no single, perfect body, and that even the celebrities she sees in the media have their bodily flaws. Point out everything that is right with her body, and discourage her from talking negatively about herself.

Healthy Habits

Encourage healthy habits with your teen girl, regardless of whether her weight is healthy. A healthy diet and lifestyle will help a teen girl with healthy weight to remain at that level; appropriate changes in diet and lifestyle will help an underweight girl gain some weight as well as help overweight and obese girls to lose some weight. Don’t encourage quick fixes or fad diets, as their results don’t last and will deprive your teen daughter of necessary nutrients. Instead, encourage portion control and healthy snacking, along with regular exercise. Make sure your daughter eats breakfast; breakfast will help to boost her metabolism. Encourage your daughter to drink plenty of water, as well, and to avoid sodas and coffees that contain empty calories.