Ideal BMI for a Woman

Body mass index, or BMI, is a straightforward body measurement that can indicate health levels and body fatness. It involves a simple calculation. Women naturally have a higher body fat percentage than men indicating a slower metabolism, which means it is easier for women to gain weight. Keeping track of your BMI will help you maintain a healthy weight, and if you are starting to creep into overweight or even obese levels, you can make the necessary lifestyle changes to reverse direction.

Facts

BMI is one of the most effective ways of indicating fatness. It is a measurement that considers your height and weight. Although it does not directly determine body fat percentage, it correlates with body fatness in average people. The higher the BMI, the more risk that you face for diseases associated with being overweight and obese. There are many problems that are associated with high BMI, so it is important to try to stay in the ideal ranges.

Calculation

In order to estimate BMI, convert your weight from pounds to kilograms, and height from inches to meters squared. Convert weight from pounds into kilograms by dividing it by 2.2. For example, a 150-lb. woman would weigh 68 kg. Convert height from inches to centimeters, and then to meters by multiplying it by 2.54 and then dividing by 100. For example, a five-foot-seven female would be 67 inches tall. Multiply that by 2.54 to get 170 cm. Divide that by 100 to get 1.7 m. To get BMI, divide weight in kilograms by height in meters squared. For this example it would be 68 divided by 2.89, which equals 23.5kg/m2.

Statistics

The American Council on Exercise states that the normal and healthy BMI range is 18.5 to 24.0 kg/m2. Overweight range is 25.0 to 29.9 kg/m2. Obesity range is 30.0- 34.9kg/m2. Severely or morbidly obese is any number above 35 kg/m2. Having a BMI under 18.5 is considered underweight and can also carry health risks. The National Health and Nutrition Examination Survey reported in 2006 that approximately 69 million women in the United States had a BMI over 25 kg/m2 and of these women, 36.7 million were obese.

Accuracy

BMI is a reliable assessment for health risk in most average women. It might not be the most accurate method for athletes or women with higher than average amounts of muscle. According to the Centers for Disease Control and Prevention, since muscle weighs considerably more than fat, a measure that's based solely on height and weight will have a higher number. For those women, a body fat test that assesses the ratio of lean tissue to fat mass is a more accurate method. Elderly people might have a lower reading than average due to bone and muscle loss even though they tend to have a higher body fat percentage.

Consequences

Having a BMI over 30 indicates increased levels of fat and can lead to hypertension, dyslipidemia and cholesterol disorders, type II diabetes and arthritis. These conditions can progress into much more serious health issues including heart disease, heart attack, stroke and cancer. A BMI under 18.5 can also carry risks of osteoporosis and malnutrition. To maintain a healthy BMI, make sure to exercise for at least 30 minutes a day, and consume a balanced diet low in saturated fats and simple sugars and high in fiber, fruits, vegetables, low-fat dairy and lean protein.