BMI vs. Waist-Hip Ratio

For a while now, there has been much talk about obesity. The rise in obesity and its associated health risks is one of the fastest growing concerns that affect everyone in every stage of life. But what is obesity? What does it mean to be obese, or overweight? What is the difference?

Overweight is simply that, being over your ideal weight. It is a state at which your body weight exceeds the standard or ideal weight based on height and/or frame size. Usually it does not exceed 20% of your ideal body weight. For instance, a 40-year-old woman that is 5’4” and weighing 140 lbs. would be considered overweight since the standard for her would be approximately 120 lbs.

Obesity on the other hand, is someone over 20% of their ideal body weight or a state in which body fat is above the ideal. Normally it can be measured as a percentage or based on BMI (Body Mass Index). A BMI of more than 30 classifies one as being obese and therefore puts one at greater risk of developing health problems. For example a man who is 5’11” weighing 220 lbs. has a BMI of 30.7, and is therefore classified as obese.

Are you shocked to find out what obesity is? All this time you thought you might be slightly overweight, but not obese. It is scary to think of it in these terms. But there are different levels of obesity, depending on the severity of developing diseases or extreme health complications.

For years, the Body Mass Index has been the most widely accepted method of determining a healthy weight. However, it’s not without its faults. In the case of an athlete, for example, body mass is not an effective basis for measurement since muscle weighs more than fat. Also some people with a high BMI, but a small waistline, may not be a high risk candidate for heart attack.

A new study to be published in the British Medical Journal, the Lancet, suggests that a better indicator of obesity would be to determine your waist-hip ratio (WHR). Scientists believe it is a better indicator than BMI, because the WHR method assesses fat distribution, BMI does not. People, who carry fat around the waist and upper abdomen, are android or “apple” shaped and are at greater risk of heart attack than those who carry in the thighs and buttocks, (gynoid or “pear” shaped.) Some people might be a blend of both having fat evenly distributed.

Android or “apple” shaped individuals have an increased risk of obesity-related diseases, such as hypertension, cardiovascular disease and diabetes. In fact, this latest research shows that WHR was three times stronger a predictor of heart attack than using BMI.

To determine your WHR follow these instructions:

  • Using a tape measure, measure the smallest area of your waist, usually just above the belly button.
  • Measure your hips, usually the widest part of your buttocks.
  • Divide your waist measurement by your hip measurement.
  • The lower the number the better. However, ideally women should have a ratio not higher than 0.85 and men not higher than 0.90.
1+ 0.95 + High
0.91-0.99 0.86-0.94 Moderate
0.90 & below 0.85 & below Low
Source: Health Status, McMaster University

More research is needed to further understand these findings. Use of the BMI should not be completely eliminated since knowing your BMI is a good start to determining whether you are overweight or not, and the more indicators the greater accuracy of the result. Fat is the indicator for obesity, which is one risk involved in developing specific diseases.

Ideally it is best not to have any excess weight however a smaller waist and bigger hips are better than having all the weight around the middle area. Regardless, living a healthy and active lifestyle will be a benefit whatever way you look at it.