Approach BMI with Caution

As an athlete, I eat well, lift weights, possess a significant amount of lean muscle mass, and have a low body fat percentage. I typically do not participate in health assessments that use Body Mass Index (BMI) as a measure of health; however, with a financial incentive, I jumped in on one last week.

My experience was worth sharing. I shouldn’t have been, but I was stunned when the nursing staff conducting the analysis blatantly told me I was overweight. Appearance alone, I knew I didn’t look overweight – I’m a size 6/8, have healthy complexion and color. In physical fitness, I have completed six Ironman competitions, teach fitness classes at my local YMCA, and workout/train six days a week. Diet-wise, I daily consume a generous amount of healthy greens, good carbohydrates and lean proteins. Overweight? While I knew that wasn’t the case, I was still stunned by the numbers and the amount of weight (pun intended) that these health professionals placed on that assessment.

Research has shown that BMI is not an accurate measure of health. It only takes into account two variables: weight and height. For those who may not be aware, BMI (a measure of obesity) is calculated by taking your bodyweight and dividing it by your height squared. Adults age 18 and older are considered overweight if they have a BMI of 25-31, and obese if the number is above 32.

Unfortunately, that’s it. That’s a key element in these traditional health assessments. There is nothing else taken into consideration when looking at healthy weight.

In a recent study, an entire New Zealand rugby team was assessed as overweight with four of them being classified as obese. The only measure was the standard BMI calculation. These men play a rough sport, so they have to be fit! Yet health professionals considered the whole team overweight. In addition, a similar report from New Zealand classified almost all athletes and bodybuilders as overweight.

What’s interesting as well is that BMI does not capture stature which includes physical build, bone density, and body fat percentage. Research has found that there are far more factors that should be taken into consideration when assessing health and fitness:

1. Body fat percentage – this captures how much of your body weight is fat. That is the key element that indicates being overweight or obese.

2. Blood pressure – the average BP is 120/80 but most athletes and healthy individuals have even lower blood pressures.

3. Resting heart rate – a lower resting heart rate indicates greater fitness and health

4. Waist measurement – fat that wraps around the middle has been found to be dangerous as it can impede blood flow and other bodily functions.

5. VO2 fitness test – this shows how much oxygen your body is able to utilize during high intensity exercise. The more usable O2, the higher the fitness.

6. pH (potential of hydrogen) – this refers to the acid/alkaline level in your body. Over acidity or over alkalinity can weaken the body. Proper pH balance in the body can actually resist disease. The body comprises 70% water, the rest contains a ratio of acid-alkaline to keep the body functioning properly. (Note: this is not stomach acid; pH refers to acid in the body’s fluids and tissues, not in the stomach as in acid indigestion.)

7. Fasting glucose – this measures the level of sugar in your blood without the presence of food. This assesses whether your body’s insulin and sugar are working effectively.

Although there are better measures of health, almost all health care professionals still rely on the antiquated BMI measurement. Thus, some people who are healthy are wrongly told that they are overweight or obese. The mental health and physical effects of such a pronouncement could be devastating potentially causing depression, eating disorders or other concerns. So, why do we still use it?

BMI is an easy and inexpensive indicator of health risks for most adults (athletes and elderly are two exceptions). More accurate assessments can be expensive. The idea is to look for very high or very low BMIs because they have the greatest risk of health problems. Because it’s simple to determine and cheap, it is the primary health risk indicator used in the medical world.

The CDC notes that BMI measures excess weight, not fat. It doesn’t differentiate between bones, muscles, organs, tissues and body fat. The CDC also admits that this tool should not be used to assess health, but rather as an indicator of potential health problems. Athletes are most likely going to have a high BMI which indicates obesity, but a very low body fat percentage.

People who obtain their BMI should not become overly obsessed with the number, because it is simply an indicator of potential problems, not an indicator of good or poor health. Additional tests and assessments combined are the best methods of determining optimal health – for YOU.

Works Used:

Academy of Nutrition and Dietetics. (2012). Understanding Body Mass Index. Retrieved from http://www.eatright.org/Public/content.aspx?id=6844.

Matte, M. (2013). What is a realistic BMI for someone athletic? Retrieved from http://www.livestrong.com/article/395464-what-is-a-realistic-bmi-for-someone-athletic/.

Natural Health School. (n.d.). pH balance. Lesson 18. Retrieved from http://www.naturalhealthschool.com/acid-alkaline.html.

Woodgate, M. (n.d.). Why BMI should be outlawed! Retrieved from http://www.bodyblueprint.co.nz/article-bmi.html.