Gaining - and Growing - what's normal?

McKenzie K captures some typical feeling girls have as they adjust to the normal body weight and shape changes that accompany puberty: "I think I'm wide, but people say I'm not. I've got that hip kind of thing going on - you know, when you develop. You have to get used to it. It takes a while, but that's who you are."

As teens who are not overweight shoot up in height, it's healthy for them to gain some weight. According to Trim Kids by child weight expert Melinda Sothern, Ph D, and colleagues, it's normal for a child to gain an average of 3 to 5 pounds for every inch that he or she grows. For girls, the growth spurt usually begins between ages ten and twelve and ends anywhere from age seventeen to nineteen. (Some findings suggest, however, that puberty may be occurring earlier than in the past, particularly among African American girls.) Girls usually grow no more than a few inches after their menstrual period begins, which is usually at age twelve or thirteen.

For boys, the growth spurt typically begins when they're 12 to 14, and they usually finish growing at about age 20, although some grow in stature into their early twenties.

Girls usually have a spurt in weight gain 6 to 9 months before their rapid growth in height, which leads some slightly overweight girls and their parents to worry unnecessarily, as they will slim down when they grow taller. In general, girls gain weight most rapidly - typically about 40 pounds - between ages 10 and 14, then again another 10 pounds by age twenty. (Of course, it would not be healthy for a teen who is overweight to gain weight like this.)

For boys, the rapid weight spurt generally occurs at the same time as the height spurt. They gain most rapidly - typically about 45 pounds - between ages twelve and sixteen, then gain another 20 pounds by age twenty.

For girst, other normal changes that occur during puberty and result in the curvier shape of a woman can affect weight, including breast "budding" (which may begin around age 10 or even earlier), widening of the hips, narrowing of the waist, and some (normal!!) buildup of fat in the belly, backside, and legs,

For boys, changes in body shape include the broadening of shoulders and the growth of muscles.

What's a comfortable weight?

• It's a weight at which you feel pretty good about yourself, given where you've been. (Yes, you'd like to weigh 120, but since you've been at 180 for a long time, could you live with yourself at 140 or 150?)
• It's a weight that you don't have to starve and exercise fanatically to maintain. (If you got to 125, would you really want to live that way to stay there?)
• It's a weight at which you have no medical problems caused by your weight. In fact, studies show that losing just 5 to 10 percent of your weight - 10 to 20 pounds for a 200 pound person - can make a big difference in your health.
  

To lose weight or wait it out?

Who should lose weight, and who should "grow into" his or her weight"? A 13 year old girl who weighs 200 pounds will not grow into her weight because that weight is too high to be healthy unless she reaches 6' tall. Recommendations from a committee of experts, published in the medical journal Pediatrics, and currently under review, state that weight loss is recommended for overweight teens who have:

• a BMI in the 95th percentile or higher.
• a BMI from the 85th up to the 95th percentile if they have medical problems, such as high blood pressure, related to their weight.

However, for teens whose weight problems are less serious - that is, those with a BMI placing them from the 85th up to the 95th percentile and without weight-related medical problems - maintenance is recommended, because they can grow into their weight through physical activity and healthy eating. For young people in this category who are finished growing, gradual weight loss would be appropriate, according to Sarah Barlow, MD, a member of the committee.

What's a safe rate of slimming down for overweight teens who meet the criteria for a weight loss? Dr Barlow says, "I'm comfortable with a teen losing at a rate of one to two pounds per week. Losing faster than that may mean that the body will start losing too much muscle tissue along with the fat, and that's not healthy. If a teen's hungry all the time, that's another sign that a diet is too strict and weight loss is too fast."

The best way to find out whether an overweight teen should be losing weight or "waiting it out," according to the guidelines, is to check with a physician.

BMI Basics

As of this writing, most health care professionals in the US use the following indicators to define weight problems in teens.

Overweight: The BMI for a teen's age and gender is greater than or equal to the 95th percentile. For instance, a sixteen year old girl who is 5'3" and weighs 175 pounds would be in the 97th percentile; a sixteen year old boy who is 5'8" and weighs 195 pounds would be in the 97th percentile. Nearly 9 out of 10 of the teens interviewed fell into this category at their highest weight; 60 were in or above the 99th percentile before losing weight.

At risk for overweight: The BMI for a teen's age and gender is anywhere from the 85th percentile upto but not including the 95th percentile. For instance, a 16 year old girl who is 5'3" and weighs 150 pounds would be in the 91st percentile; a sixteen year old boy who is 5'8" and weighs 169 pounds would be in the 91st percentile. Just 7 of the teens interviewed fell into this category at their highest weight; none were below this category.

(BMI percentiles were not available for a small number of the teens at their highest weight.)

How much weight is too much?

From a health standpoint, what's a healthy weight, and at what weight is a person at risk for developing health problems? Several studies suggest that many teens don't know when they've reached an unhealthy weight - and neither do their parents. In fact, the considerations are different for adults and teens. For adults, the gold standard for defining healthy weight is something called body mass index, or BMI, a number that measures weight in relation to height. When an adult's BMI is 25-plus, health risks increase compared with someone who has a BMI of less than 25; 25 to 29.9 is considered overweight, and 30 or above is obese. (BMI is calculated by dividing weight in pounds by the square of height in inches, then multiplying that number by 703. BMI charts are available in books, at doctors' offices, and on many health-related Web sites.)

For children and teens, the picture is more complicated, because what's considered a healthy weight and normal amount of body fat changes with age and differs in boys and girls. The best way to determine a teen's weight status is to consult a physician and to use special pediatric growth charts developed by the Centers for Disease Control and Prevention for children ages two through nineteen. These charts plot weight according to percentiles for kids of the same age, gender, and height. (The Centers for Disease Control and Prevention provides an interactive computerzied BMI calculator that does the work for you. Visit this Web site: http://apps.nccd.cdc.gov/dnpabmi/calculator.aspx.)

BMI and the BMI growth charts are only rough guides for a healthy weight. For instance, some teens fall into the "at risk" category for being overweight becuase they're muscular, not because they hae excessive body fat levels.

It's also important not to go by any single measure of BMI percentile for a child or teen. Rather, BMI percentile should be watched over time to see if a child is staying on track. According to Roman Shypailo, a body composition expert at the Baylor College of Medicine, "The important thing is to watch for significant 'drifting' in a teen's BMI percentile, either up or down." In other words, if there's a sudden large increase or if a teen creeps up by three or four units every year, that's probably cause for concern. But if he or she has been on the same track for years - even if it's somewhat on the high side - there's less reason to worry.

Although it's unwise for kids and their parents to be obsessively calculating BMI and BMI percentile, it's probably a good idea to calculate them periodically, with a physician's help.

Choosing words for weight

Obese. Fat, Overweight. These words bring pain and shame to those so labeled.

"Obese" is a clinical term used to describe someone with excessive body fat tissue who is quite overweight. Because the word "obese" is considered stigmatizing, many weight experts shy away from it, particularly when referring to children and teens. Instead, they tend to use the word "overweight" to describe young people who would be considered medically obese. "At risk for overweight" is a common term for kids whom most people would consider to be overweight or somewhat overweight.

"Fat" has no standard medical definition, but it's commonly used to describe both obese and overweight people. It's preferred by some people who feel that the word "overweight" implies an "ideal" standard, when, in fact, a variety of weights can be healthy for individuals of a particular height.

For lack of a better term, we should generally use "overweight" to describe teens who would be considered medically overweight or obese, as does New York University's Sharron Dalton, Ph D, RD, in her book Our Overweight Children. Terminology aside, the important thing is for each teen to find a weight that's not only healthy for him or her but also realistic and comfortable to maintain.