A burgeoning waist line may be doing more than keeping you out of your tight jeans; it could be shortening your life. Your waist size and body mass index are important indicators of increased health risk due to excess body fat. While BMI is the primary measurement used by health professionals to classify people as overweight or obese, waist measurements are an independent and telling indicator of increased health risk.
Waist Size Matters
In a study of 13,000 participants followed for 14 years, researchers found that people of normal weight, but with excess belly fat, had the highest risk of death -- higher even than individuals classified as obese. A 2010 study published in "JAMA Internal Medicine" found increased waist size was associated with increased risk of death in older adults, regardless of BMI. Those with the largest waist measurements had twice the risk of dying over a nine-year period than those with the smallest waists. Every four-inch increase in waist size was associated with a 25 percent increase in risk of death.
What's a Healthy Waist Measurement?
Women should aim for a waist measurement below 35 inches, and men below 40 inches. A waist measurement of 35 or more in women and 40 or more in men has been linked to increased risk for type 2 diabetes, high cholesterol, high blood pressure and cardiovascular disease. This increased risk was found even when associated with a normal BMI. These guidelines are applicable to most people, however if you are under five feet tall, waist-to-height ratio is more meaningful. Aim to keep you waist measurement less than half your height.
Body Mass Index
BMI is a measure of weight relative to height. While it is not a direct measure of body composition, it does correlate with body fat across the general population. According to the National Heart, Lung and Blood Institute, increased BMI has been linked to an increased relative risk for cardiovascular disease and early death. Keep in mind that BMI is just one factor to consider and can be inaccurate when applied to particular individuals. For example, BMI may underestimate fatness for an elderly person who has lost a great deal of lean muscle mass while classifying a fit, well-muscled person as overweight.
What's a Healthy BMI?
To calculate BMI, divide your weight in pounds by your height in inches squared. Then multiply by 703. A BMI of 18.5 to 24.9 is considered normal, 25 to 29.9 is classified as overweight, and 30 and above is considered obese. But don't be lulled into complacency if your BMI falls in the normal range. Check your waist measurement too. According to the National Heart, Lung and Blood Institute, while BMI and waist size are interrelated, waist size alone provides an important indicator of health risk. Even if your BMI is normal, if you have excess weight around the middle, you are at increased risk for disease and early death.
- National Heart, Lung and Blood Institute: Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults - The Evidence Report, According to Waist Circumference
- JAMA Internal Medicine: Waist Circumference and All-Cause Mortality in a Large US Cohort
- National Heart, Lung and Blood Institute: Assessing Your Weight and Health Risk
- U.S. News and World Report Health: For Good Health, Watch Your Waist Size, Not Just Your Weight
- Mercola: Your Waist Size Can Be a Powerful Predictor of Hypertension and Other Chronic Diseases
- National Heart, Lung and Blood Institute: Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults - The Evidence Report, According to BMI
- Medical News Today: Waist to Height Ratio Better than BMI
- Centers for Disease Control an Prevention: About BMI for Adults