Do you know your body mass index (BMI)? BMI is a tool to find weight to height ratio and check if body weight is normal, overweight or obese. Although it is a screening method to assess weight, it does not directly measure body composition or body fat. In order to get a more detailed picture of weight assessment, both BMI and body fat percentage should be obtained.
Identification
BMI is calculated using the mathematical formula: weight (lb) / [height (in)]2 x 703. For example, if you are 150 pounds and five feet, seven inches tall, the calculation would be: 150/67 X 67, which is .033415. Multiply this number by 703, and the result is a BMI of 23.5, which would be considered a normal weight. According to the Centers for Disease Control (CDC), a BMI below 18.5 is underweight, 18.5 to 24.9 is normal, 25 to 25.9 is overweight, and 30 and above is obese. Another way to calculate your BMI is to use a BMI calculator, which can be found on the CDC website. There is a separate calculator for adults, and one for children and teenagers.
Body Fat
Once you know your BMI, further assess your body weight to find out how much of it is composed of body fat and muscle. You can get a body fat assessment done by a trained health care professional through a triceps skinfold measurement, or through a bioelectrical impedence scale, which delivers small electrical currents through the body to measure body fat. Proper hydration is required to get more accurate results using bioelectrical impedence. Another method includes underwater weighing, which can assure the most accuracy--however, it is done in a lab and is costly.
Body Fat Percentage Guidelines
According to the American College of Sports Medicine, body fat percentage guidelines for women are: normal is 22 to 25 percent, above average is 25 to 29 percent, over fat is 29 to 35 percent, and obese is 35 percent and over. For men, normal is 15 to 18 percent, above average is 18 to 20 percent, over fat is 20 to 25 percent, and obese is 25 percent and over. For athletic women, the guideline is under 17 percent, and for athletic men, under 10 percent body fat.
Health Effects of Increased Body Fat
If you have a body fat percentage that is higher than normal, it can be unhealthy. According to the American Heart Association, excess fat, especially in the abdominal area, can increase risk for diseases such as heart disease, high blood pressure, high cholesterol and stroke. The American Heart Association recommends waist measurements to measure body fat. A waist measurement of 35 inches or more in women, and 40 inches or more for men, are considered high risk waist measures.
How to Lower BMI and Body Fat
Calorie control and regular physical activity is the best way to lower your BMI and body fat percentage. You should focus on slow and gradual results rather than rapid weight loss. Gradual weight loss and fat loss tends to be more permanent. You can find out how many daily calories you need based on your activity level by using an online basal metabolic rate calculator at CaloriesPerHour.com. Regarding physical activity, the American College of Sports Medicine recommends 30 minutes of moderately intense cardiovascular activity five days per week. To lose weight or maintain weight loss, 60 to 90 minutes could be required. They also recommend weight training exercises two times per week.
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