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What Is Obesity?

Human weight is a big problem in America—in more ways than one. Obesity, the condition of having an excessive amount of body fat, has become such a serious concern that health professionals have begun to attach the “E” word to it: epidemic.

If you’re in the “overweight” or “at risk” zones of the national Centers for Disease Control and Prevention’s (CDC’s) Body Mass Index (BMI) chart, it indicates you probably are too heavy for your height and age. You have lots of company. One in three American children between the ages of six and nineteen has a significant weight problem. As of 2002, the National Center for Health Statistics found that 16 percent of young people in that age range were considered overweight; another 15 percent were considered at risk of becoming so. Three times as many children are overweight now than were overweight thirty years ago.

Sharron Dalton, in her book Our Overweight Children: What Parents, Schools, and Communities Can Do to Control the Fatness Epidemic (2004), reported on a recent study that traced the stature of thousands of children. By the time they were nineteen, almost half of the white girls and more than half of the African American girls were heavier than they should be.

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Health officials are especially concerned about weight problems among children. Over the past three decades, the number of overweight children in the United States has tripled. In 2009 it was reported that approximately 14 percent of preschoolers were overweight; children aged six to eleven, almost 20 percent; and adolescents aged twelve to nineteen, over 17 percent. More than 20 percent of American children from the ages of three to five are believed to be either overweight or at risk of becoming so. Automakers are designing larger safety seats to accommodate overweight preschoolers.

Research suggests that most Americans today weigh too much. In 2006, about 65 percent of American adults ages twenty and older were overweight and nearly 25 percent were obese, according to the National Center for Health Statistics. The percentage is rising. As recently as the mid-1990s, “only” 55.9 percent of Americans were overweight.

What Is a “Normal” Weight?

There are different shades of “normal,” “thin,” and “fat.” A muscular athlete might be 6 feet (1.8 m) tall, weigh 220 pounds (100 kg), and be considered normal or average in weight and build. A non-athlete who’s 6 feet tall and weighs 220 pounds, whose weight consists mainly of fat tissue rather than muscle tissue, is overweight. Weight should be considered in relation to such other factors as height, age, and rate of growth.

The first growth charts for determining appropriate weight levels came out in the 1970s. In 2000, the CDC, an agency within the U.S. Department of Health and Human Services (HHS), introduced more accurate charts. These charts reflected what has become known as the Body Mass Index, or BMI. BMI charts are formulated to help you determine whether you are at a healthy, unhealthy, or at-risk weight.

Generally, a BMI rating of 25 to 29 is considered overweight; people with a BMI score of 30 or above are considered obese. Defining obesity, though, isn’t a simple matter of calculating weight and height. For example, BMI interpretations vary slightly for those under age twenty because the body’s natural fat ratios change during normal growth. Average fat percentages also differ between young males and young females.

The BMI is a mathematical formula: your weight (in kilograms) divided by the square of your height (in meters). The measurements can easily be converted to pounds and inches. To quickly calculate your BMI in pounds and inches, use this formula:

  1. Compute the square of your height (multiply your height times itself) in inches.

  2. Multiply your weight in pounds by 703.

  3. Divide the weight result by the height result.

Sample results: If you are 5 feet (60 inches) tall and weigh 112 pounds, your BMI is approximately 22. Whether this is a low, average, or high weight depends on your age, sex, and other factors. A BMI of 23 or higher, for instance, indicates a weight problem for a girl at age 10. By the time she’s 16, however, the same BMI suggests no problem—in fact, at that age, she could register a BMI of 28 and be considered only “borderline” in terms of overweight risk. An average BMI for a child in the first grade is approximately 16. An average BMI for a high school senior is approximately 22.

Doctors chart the BMI in relation to your age. Different charts are used for young males and young females. If your BMI ranks in the ninety-fifth percentile or above, you’re considered overweight. If it falls between the eighty-fifth and ninety-fourth percentile, you’re said to be at risk of developing an excess weight problem.

The BMI is not a perfect tool for determining a person’s desirable weight. (Health officials have stopped using the term “ideal weight.”) Results may vary from child to child, for complex reasons. For example, the BMI does not take growth rate into account.

Growth charts, a BMI calculator, and explanatory information can be found at the Web site of the CDC at http://www.cdc.gov/nccdphp/dnpa/ bmi/childrens_BMI/about_childrens_BMI.htm.

Many experts believe mild levels of excess fat don’t notably endanger a person’s health. One study has suggested that a forty-five-year-old man at 20 percent above his “ideal weight” has a life expectancy only a few months shorter than “healthy” men his age. Moderately overweight women are believed to be less at risk than men.

Where excess weight is distributed around your body, however, could be a significant factor in how seriously your health is at risk. Although many females fret over unattractive figures caused by fatty thighs and hips, more dangerous is massive fat around the middle to upper body, surrounding the vital organs.

Separating Fat from Fat

A nagging problem with efforts to address the obesity problem has been incomplete and sometimes faulty information about what causes it. For example, after nutritionists cited saturated fat as a health culprit in the late 1900s, food companies began reducing saturated fat content in their products. In many cases, they substituted trans fat—which was soon pronounced to be more harmful than saturated fat.

Many people assume that all fat is bad. The reality is that a body needs a certain amount of fat to function. It’s a primary source of energy. It’s vital to cell composition and to your chemical makeup.

Trans fat, however, has been heavily criticized for its role in obesity. Scientists have found that excessive consumption of trans fat can build up cholesterol in the blood and lead to heart disease. Nutritionists suggest that trans fat and saturated fat should account for less than 10 percent of the calories you consume, but many Americans double that amount. Various packaged desserts, french fries, potato chips, greasy burgers, and pastries are high in trans fat. Fast food restaurants in particular have come under fire for the levels of trans fat contained in their fries.

Sweetened, carbonated soft drinks are another primary target in the anti-obesity war because they are high in nonessential sugar content. The average American drinks about twice as much soda today as in the 1980s.

Dietary Guidelines

The federal government’s MyPyramid (formerly known as the Food Guide Pyramid) is a general guide to what kinds of foods (and how much of them) you should eat. It was developed by the U.S. Department of Agriculture (USDA) and the HHS and is based on the Dietary Guidelines for Americans, which are updated every five years. The USDA and HHS realized that the ideal amount of food intake differs depending on a person’s age, gender, and daily activities. In 2005, they provided a Web site, http://www.mypyramid.gov, which includes an interactive food guidance system and which customizes a healthy eating and exercise plan for each individual.

The MyPyramid symbol on the site shows colorful vertical slices or bands to indicate generally the comparative amounts of the six food groups you should include in your daily diet. The varying widths of the slices represent how much food you can choose from each group, and is to be used as a guide rather than as exact amounts. The narrowing of each food group slice from bottom to top stands for eating foods in moderation. The foods at the base, where the pyramid is widest, are those foods with little or no solid fats or added sugars. These foods should be chosen more often.

The six colored slices represent the six food groups, and show that food from all the groups are needed daily for a healthy life. The orange slice, the widest band, represents the grains group; the green slice is the vegetable group; the blue slice is the milk, yogurt, and cheese group; the red slice represents the fruit group; the purple slice indicates the meat and bean group; and the yellow slice represents oils, such as vegetable oils, nuts, and avocados. On the site’s “Inside the Pyramid” page (http://www.mypyramid.gov/pyramid/index.html), when you click on one of the slices, you’re shown common examples of the foods in that group and advice on which ones are considered best to eat.

Some medical professionals believe that the pyramid plan or model might be improved. For now, though, it is a valuable guide for weight management.

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Article Citation:

Harmon, Daniel. "Obesity." Teen Health and Wellness. Rosen, 2010. Web. 24 Aug. 2010. <http://www.teenhealthandwellness.com/article/249/obesity>.