Body mass index, or BMI, is a simple tool that can help determine an individual's risk for chronic and/or life-threatening disease. While not an exact measure of body fat, it does give an indication of percent body fat. When calculating life expectancy, other factors must also be considered along with BMI and a physician can make a determination based on overall personal health.
Identification
Body mass index is just one tool used to identify the risk for developing serious diseases. BMI is a number that is calculated using current weight and height. BMI can be plotted on a chart or determined mathematically. For adults, take current weight in pounds and multiply by height in inches squared. Then multiply this answer by a conversion factor of 703. According to the National Heart, Lung and Blood Institute, the higher the BMI, the higher the risk of disease and death. However, it should not be the only tool used, because it can overestimate BMI for athletes who have a high percentage of muscle mass and underestimate BMI in older individuals who have lost muscle mass. Children have special formulas and diagnostic tools to determine overweight and obesity based on gender and age.
Considerations
Once BMI reaches 25.0 to 29.9, a diagnosis of overweight is made; a BMI over 30 indicates obesity, according to the Centers for Disease Control and Prevention. Being overweight or obese raises the risk of developing life-threatening diseases. This includes high blood pressure, heart disease, heart attack, stroke, diabetes and some forms of cancer. A BMI of 18.5 or lower is considered underweight, which can also be life-threatening if left untreated.
Warnings
Carrying extra pounds can decrease life expectancy; it is estimated that obesity causes approximately 300,000 deaths in the United States each year, claims the Office of the Surgeon General. According to the University of Oxford, a BMI of 30 to 35 decreases life expectancy by three years. Those who have a BMI of 45 or higher may live up to 10 to 20 years less than people who are not overweight, reports the National Institutes of Health. These rates were similar to the death rates of smokers. While obesity raises the risk of all chronic diseases, the most common cause of death is heart disease. However along with BMI, waist measurement, waist to hip ratio, smoking habits, eating an unhealthy diet and being sedentary also play a role in life expectancy rates.
Solution
The good news is that losing even just 5 to 10 percent of current weight reduces the risk of disease and death. Setting small goals can make reaching total weight loss goals more achievable. Unless under a doctor's care, safe weight loss is about 1 to 2 lbs. per week. This allows for gradual changes to lifestyle behaviors that can be maintained throughout life. This ensures that the weight lost will not be regained. Weight loss involves taking in less calories than are burned off while eating a healthy, well-rounded diet and getting regular exercise.
References
- National Heart, Lung and Blood Institute: Assessing Your Weight and Health Risk
- Centers for Disease Control and Prevention: About BMI for Adults
- National Institutes of Health: Obesity Threatens to Cut U.S. Life Expectancy, New Analysis Suggests
- University of Oxford: Moderate Obesity Takes Years off Life Expectancy
- Office of the Surgeon General: Overweight and Obesity: Health Consequences
Member Comments