What Is A BMI and Why Should I Care?

Posted by Dave Tomar on February 05, 2014

What Is A BMI and Why Should I Care?

There are no two ways about it. Obesity is a killer. The connection between your waistline and your life expectancy is grounded in sound science. Adults who are overweight are at a far greater risk for diabetes, stroke and heart disease. But how do you what your ideal weight is? That’s what the Body Mass Index is for.

What Is BMI?

Body Mass Index (BMI) is a fancy way of describing the correlation between your height and weight. Though everybody has a different body type, there is an ideal range of weight for your height. Your BMI provides an evaluation of your weight based on this height. This evaluation tells you weather you are considered underweight, healthy, overweight, obese or high-risk.

Medline Plus provides a handy table breaking down the implications of each BMI range. Depending on where you fall in this range, your BMI might offer evidence that it’s time for a lifestyle change.

What About My Health?

This is because a high BMI can have serious health implications, especially for the elderly. According to the Journal of General Internal Medicine, roughly two thirds of individuals over the age of 60 are living with obesity. This means that the vast majority of senior citizens may be at an elevated risk for the wide range of conditions correlated to obesity.

For senior citizens living with an extremely elevated BMI, typically classified as 40 or higher, changes in diet, exercise and lifestyle are a must. Of course, BMI is useful for identifying health risks for those on the opposite end of the spectrum as well. A lower than normal BMI for one’s height may be an indication that unwanted fat, muscle or bone loss may be occurring. An extremely low BMI can also indicate heightened health risks.

According to the Journal of General Internal Medicine, those on the lower end of the BMI spectrum may actually suffer a higher risk of mortality from certain conditions such as congestive heart failure, rheumatoid arthritis and renal failure.  A little extra weight may actually provide the body some protection against the impact of sickness.

Should I Panic?

No. Don’t panic. Your BMI is a surface level indication of your ideal weight but it is an indicator with genuine limitations. You should know that your recommended BMI range is not a hard and fast rule. There are a number of factors that might distort the meaning of your BMI. For instance, because muscle has more mass than fat, weightlifters and other athletes may find that they routinely exceed the suggested BMI for their height. This is normal and healthy provided you keep up with your active lifestyle.

What Should I do?

The basic takeaway is that an extreme BMI at either end of the spectrum carries health risks. Your best bet is to shoot for the 18.5 to 24.9 range that Medline calls healthy. However, Nutrition 411 warns that the implications of BMI may be slightly different for seniors, especially for those who fall on the ‘underweight’ side.  A physician is more likely to recommend nutritional intervention for a senior with a low BMI than for a teen or middle-aged adult. In a general sense, you should treat your BMI the same way you treat the number on your bathroom scale. If it’s too high, diet and cardio. If it’s too low, ‘good’ calories and strength training.  In either event, if you are unhappy with your BMI, ask your doctor for some suggestions on healthy and manageable lifestyle changes.


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