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What is Body Mass Index (BMI) and how do I calculate it?

BMI is a number calculated from your weight and height that tends to correspond with your body fat. BMI ranges for children and teens take into account normal differences in body fat between boys and girls and differences in body fat at various ages.

Among children and adolescents, overweight and obesity are defined using age growth charts.

Link to BMI calculator:

What is the difference between being overweight and being obese?

The difference has to do with your Body Mass Index (BMI). Overweight is defined as a BMI at or above the 85th percentile and lower than the 95th percentile. Obesity is defined as a BMI at or above the 95th percentile for children of the same age and sex. For children and teens, BMI ranges above a normal weight have different labels (at risk of overweight and overweight).

Classes Body Mass Index (BMI)
Underweight Less than 18.5kg/m2
Normal 18.5 - 24.9
Overweight 25 - 29.9
Obesity 1 20 - 34.9
Obesity 2 34.9 - 39.9
Morbid Obesity 40

What physical and emotional health problems does being overweight or obese cause in adults and children?

  • Diabetes (high sugar) and insulin resistance
  • Heart disease (clogged arteries)
  • Cancers (endometrial, breast, and colon)
  • Hypertension (high blood pressure)
  • High total cholesterol levels, high LDL cholesterol levels (the bad kind), and/or high levels of triglycerides (fat)
  • Low HDL Cholesterol (the good kind) levels in the blood
  • Stroke
  • Liver and Gallbladder disease
  • Sleep apnea (snoring that causes one to stop breathing) and respiratory problems
  • Gynecological problems (abnormal periods, infertility)
  • Early puberty
  • Orthopedic problems (joint pains, arthritis)
  • Depression*
  • Poor Body Image *
  • Low Self-Concept *
  • Risk for Eating Disorders *

*Children and teens are especially at risk for developing these problems.

What factors contribute to children being overweight, obese or at risk for becoming overweight?

  1. Food Choices
    • High calorie diets (including fats and simple sugars) and those low in fruits and vegetables are linked with being overweight.
  2. Physical Activity
    • Weight gain occurs when children spend less time participating in physical activity and more time doing activities such as watching TV that burn fewer calories.
  3. Parental Obesity
    • Children of obese parents are more likely to be overweight themselves.
    • There is an inherited component to childhood overweight/obesity that makes it easier for some children to become overweight than others.
    • Parental obesity may also reflect a family environment that promotes over- eating and little activity.
  4. Eating Patterns
    • Skipping meals or not maintaining a regular eating schedule can lead to over-eating.
  5. Parenting Style
    • Some researchers believe that parents who overly control their children's eating habits, may contribute to obesity by preventing children from being able to learn how to regulate what they eat.
  6. Diabetes during pregnancy
    • Overweight and type 2 diabetes in children occur with greater frequency in the children of diabetic mothers (who are also more likely to be obese).
  7. Low Birth Weight
    • Low birth weight is suggested as a risk factor for childhood overweight/obesity in several studies.
  8. Excessive weight gain during pregnancy
    • Several studies have shown that mothers who gain too much weight during pregnancy have children with an increased birth weight that become overweight later in life.
  9. Formula Feeding
    • Breast feeding is generally recommended over formula feeding. Several studies suggest that breast feeding may prevent excess weight gain as children grow if the mother maintains a healthy diet while breast feeding.
  10. Parental Eating and Physical Activity Habits
    • Parents with poor eating habits and who are inactive role model these behaviors for their children.
  11. Demographic Factors
    • There is evidence that African American and Hispanic children 6 to 11 years old are more likely to be overweight than are Caucasian children of the same age. Asian and Pacific Islander children of the same age were slightly less likely to be overweight.
    • Hispanic boys and African American girls are the highest risk groups.
    • Higher income level and having at least a college education are associated with a decreased risk of obesity.

If you lose weight and get healthy, can the problems obesity causes be fixed?

Yes. Diabetes-related health complications can be decreased. A diabetic's need for medications can be decreased and blood sugar levels can be lowered. Type II diabetes can even be reversed if enough weight is lost. High blood pressure can be decreased with weight loss, along with the need for medications to treat the high blood pressure. Lung function can improve in asthmatics that lose weight. This improves quality of life, decreases the amount of attacks, and possibly decreases the medication doses. Sleep apnea is more common in overweight individuals. Losing weight improves sleep quality and decreases daytime sleepiness. Weight loss lowers heart disease risk, lowers cholesterol levels (which contribute to clogged arteries), and reduces the risk for bad outcomes in those with heart disease. Individuals who lose weight report improved self-esteem, increased energy level, and improved mood.

How bad is the problem in Virginia?

The good news is that Virginia's rate of obesity is below the national level. The bad news is it is still above the Healthy People 2010 target of 15% and Virginia ranks 28th in the country in obesity rates (2009).