Childhood obesity is a large and rapidly growing problem. 35% of American children are now overweight, and the proportion increases each year. What's worse, is that the problem is not recognized. A study in the July 2000 issue of Pediatrics showed both parents and children are surprisingly poor at judging what weight was appropriate. Forty-seven percent of teens who reported that they were very overweight were not obese at all, according to objective body mass index (BMI) calculations. But among teens whose BMIs were at the obesity level, most parents and the children themselves did not think they were overweight!

Is your child overweight? Underweight? To calculate their BMI, use the following formula. BMI = (W x 704.5)/H2 where W = weight in pounds and H = height in inches. For example, if your child is 5 feet tall and weighs 155 pounds, then calculate their BMI first by multiplying their weight by 704.5 (the original formula is metric, 704.5 is the conversion factor), so 150 x 704.5 = 109157.5, then their height in inches 60 x 60 = 3600, then dividing, 105675/3600 = 30.33

BMI is close, but not perfect guide, as there are some factors it doesn't account for (for example, a very athletic child might be carrying a lot of weight as muscle, and so a higher BMI does not necessarily indicate that they are overweight). As an approximate guide, a BMI over 25 indicates overweight, over 27 is very overweight, and over 30 is obese. Thus our example of the 5', 155 lb. child is one who is obese.