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How Are Overweight and Obesity Diagnosed?

The most common way to find out whether you're overweight or obese is to figure out your body mass index (BMI). BMI is an estimate of body fat, and it's a good gauge of your risk for diseases that occur with more body fat.

BMI is calculated from your height and weight. You can use the chart below or the National Heart, Lung, and Blood Institute's (NHLBI's) online BMI calculator to figure out your BMI. Or, you health care provider can measure your BMI.

Body Mass Index for Adults

Use this table to learn your BMI. First, find your height on the far left column. Next, move across the row to find your weight. Weight is measured with underwear but no shoes.

Once you've found your weight, move to the very top of that column. This number is your BMI.

Height 21 22 23 24 25 26 27 28 29 30 31
4'10" 100 105 110 115 119 124 129 134 138 143 148
5'0" 107 112 118 123 128 133 138 143 148 153 158
5'1" 111 116 122 127 132 137 143 148 153 158 164
5'3" 118 124 130 135 141 146 152 158 163 169 175
5'5" 126 132 138 144 150 156 162 168 174 180 186
5'7" 134 140 146 153 159 166 172 178 185 191 198
5'9" 142 149 155 162 169 176 182 189 196 203 209
5'11" 150 157 165 172 179 186 193 200 208 215 222
6'1" 159 166 174 182 189 197 204 212 219 227 235
6'3" 168 176 184 192 200 208 216 224 232 240 248

This table offers a sample of BMI measurements. If you don't see your height and/or weight listed on this table, go the NHLBI's complete Body Mass Index Table.

What Does Body Mass Index Mean?
 

BMI  
18.5–24.9 Normal weight
25.0–29.9 Overweight
30.0–39.9 Obese
40.0 and above Extreme obesity

Although BMI can be used for most men and women, it does have some limits. It may overestimate body fat in athletes and others who have a muscular build. BMI also may underestimate body fat in older people and others who have lost muscle.

Body Mass Index for Children and Teens

Overweight are obesity are defined differently for children and teens than for adults. Children are still growing, and boys and girls mature at different rates.

BMIs for children and teens compare their heights and weights against growth charts that take age and sex into account. This is called BMI-for-age percentile. A child or teen's BMI-for-age percentile shows how his or her BMI compares with other boys and girls of the same age.

For more information about BMI-for-age and growth charts for children, go to the Centers for Disease Control and Prevention's BMI-for-age calculator.

What Does the BMI-for-Age Percentile Mean?

BMI-for-Age Percentile  
Less than 5th percentile Underweight
5th percentile to less than the 85th percentile Healthy weight
85th percentile to less than the 95th percentile Risk of overweight
95th percentile or greater Overweight

Waist Circumference

Health care professionals also may take your waist measurement. This helps screen for the possible health risks related to overweight and obesity in adults.

If you have abdominal obesity and most of your fat is around your waist rather than at your hips, you're at increased risk for coronary heart disease and type 2 diabetes. The risk goes up with a waist size that's greater than 35 inches for women or greater than 40 inches for men.

You also can measure your waist size. To do so correctly, stand and place a tape measure around your middle, just above your hipbones. Measure your waist just after you breathe out.

Specialists Involved

A primary care doctor (or pediatrician for children and teens) will assess your BMI, waist measurement, and overall health risk. If you're overweight or obese, or if you have a large waist size, your doctor should explain the health risks and find out whether you're interested and willing to lose weight.

If you are, you and your doctor can work together to create a treatment plan. The plan may include weight-loss goals and treatment options that are realistic for you.

Your doctor may send you to other health care specialists if you need expert care. These specialists may include:

  • An endocrinologist if you need to be treated for type 2 diabetes or a hormone problem, such as an underactive thyroid.
  • A registered dietitian or nutritionist to work with you on ways to change your eating habits.
  • An exercise physiologist or trainer to figure out your level of fitness and show you how to do physical activities suitable for you.
  • A bariatric surgeon if weight-loss surgery is an option for you.
  • A psychiatrist, psychologist, or clinical social worker to help treat depression or stress.
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July 13, 2012