Bmi Vs. Waist To Hip Ratio

You may pay little attention to your health until one morning you step onto your bathroom scale and gasp in horror that you have suddenly gained 5 lbs. Perhaps you recently changed your diet or exercise program. The number on your bathroom scale may reveal little about your overall general health. Body mass index and waist-to-hip ratio are contemporary standards for measuring body composition, tendency towards overweight or obesity, and potential risk for certain medical conditions.

Body Mass Index

BMI is a simple calculation of body composition that considers whether your weight is ideal for your height. BMI is derived from an equation that is equal to body weight in kilograms divided by height in meters squared. Fortunately, there are readily available calculators on the Internet such as the one on the NHLBI's site so you can input your height and weight to calculate your BMI. The BMI calculation will give a reading of underweight, normal, overweight or obesity. There are also BMI tables on the site that you can review to see which weight is ideal for your height. Physicians use these tables to encourage their patients and to help choose goal weights consistent with normal BMIs.

Waist-to-Hip Ratio

WHR is another useful measurement of body composition. Simply measure your waist across your belt-line, in inches. Do this again for your hips at their widest point, across the buttocks. The University of Maryland Medical Center has a useful WHR calculator. If you are shaped more like a pear, with a smaller waist and bigger hips, then your ratio would be less than 1, which is more desirable. However, if you are shaped more like an apple, with a larger waist and smaller hips, your ratio would be greater than 1, which is less desirable. If your waist alone measures 40 inches or more if you're a man, or 35 inches or more if you're a woman, this could indicate you may be at an increased risk for some medical conditions, including heart attack, stroke, adult onset diabetes, sleep apnea and some cancers.

Limitations

BMI may be misleading. If you appear thin or have small bones but still carry a decent amount of body fat, your BMI might fall in the underweight or normal categories, and you would be falsely reassured. Likewise, if you are a weightlifter with low body fat, but a high percentage of muscle, your BMI may indicate overweight or obesity. WHR is a bit more straightforward and also may be a more accurate indicator of overall mortality risks. However there are other more accurate, yet cumbersome ways to measure body fat such as skinfold measurements with calipers or underwater weighing. You should consider all of your own personal data before assessing your health risks and/or embarking on any drastic changes to your diet and exercise program.

Healthy Living

Considering that BMI and WHR are simply measurements, they can help you somewhat to assess your general health, but they cannot offer you further guidance. Two people with different weights and body fat percentages may still have acceptable BMIs and/or WHRs but could be at risk for common health conditions due to many other factors, such as genetic propensity or environmental exposure. Before embarking on a new diet or exercise program, see your doctor to evaluate your general health and risks for common diseases, such as heart disease, diabetes, thyroid disease, high blood pressure and cancer. Use BMI and WHR to measure your progress and continue to strive for a healthier lifestyle.