BMI (Body Mass Index) is a tool used in the medical community that pits your weight against your height, compares you against what is “normal,” and places you into a category of underweight, normal, overweight or obese. While a medical tool, BMI lacks the ability to adjust for gender, age and muscular density. So the question is, is BMI an appropriate way to measure your fitness and physical health or is BMI obsolete?
BMI is an effective tool when viewing the health status of a population and is a good predictor of disease on this level. The majority of people in the United States do not belong to a fitness club, do not exercise and do not do any thing to tone their muscles and trim their fat. If you are taking part in any of these activities, a BMI measurement will probably give you a poor and possibly dangerously inaccurate view of your body.
To get an idea of what BMI looks like, let's compare popular athletes to other celebrities. Note: these figures are for familiarization and not an example of an “ideal body type;” if these athletes and pop culture personalities are not familiar in your mind, Google images can assist you imagining them.
Underweight = <18.5
Normal weight = 18.5–24.9
Overweight = 25–29.9
Obesity = BMI of 30 or greater
Athlete McKayla Maroney, 5’2”, 102 pounds, BMI 18.5
-2012 Olympic gymnastics gold medalist, internet meme
Celebrity Miley Cyrus 5’5”, 115, pounds, BMI 19.1
-Your teen’s anti-role model, singer
Athlete Chris Johnson, 5’11”, 203 pounds, BMI 28.3
-NFL running back, over 8,000 rushing yards, 40 yard dash record holder
Celebrity Adele, 5’9”, 197 pounds, BMI 29.1
-Singer, self described “curvy” body type, target of Hollywood fat jokes
Athlete Mike Tyson, 5’10”, 220 pounds (fighting weight), BMI 31.6
-World class boxer
Celebrity Danny McBride 5’10”, 225 pounds, BMI 32.3
-Actor with minor roles in “Superbad,””Due Date,” and portrays an athlete in “Eastbound and Down” in a satirical manner
Although the athletes and celebrities are similar in BMI and weight, the athletes have noticeably lower body fat content, appear leaner and more toned. If all six of these individuals were to be measured based off of BMI only, Mike Tyson and Danny McBride would show as obese and highest risk to develop diseases related to obesity. In reality, Adele likely has the highest risk of disease followed by Danny McBride.
Measure Body Fat Percentage Instead of BMI
Body fat percentages are a much better predictor of your current health and future goals than BMI. Why? As mentioned above, BMI focuses strictly on height and weight. It does not account for age or gender.
Women naturally have a higher body fat percentage than men due to biology. As we age, we accumulate visceral fat, inside of our bodies around our organs. Overall body fat will increase regardless of fat at the surface.
Someone who is lower on the BMI chart may have a high amount of fat and low muscle mass resulting in a poor body fat reading and the possibility of declining health. Conversely someone with a low amount of fat and a high muscle mass could have an excellent body fat reading, but be considered obese by the BMI chart.
How Do You Measure Body Fat Percentage?
There are several ways we can measure body fat. A sports club like Five Seasons will use body fat calipers and bioelectrical analysis. Bioelectrical analysis is the easiest method as it is very quick and easy. However, calipers will have a slightly higher accuracy than bioelectrical analysis even though they're moderately invasive and time consuming.
If you're trying to get healthy and have concerns about your BMI and body fat percentage, don’t worry about matching the body style of any cultural figures mentioned above. The only person you can compare yourself to is you. If your workouts leave you feeling better, looking leaner and getting stronger, then you're seeing success. Don’t be concerned with the number on the scale, and don’t skip meals. If you need help planning a weight loss or muscle building regimen consult a trainer to receive workouts, nutrition recommendations, body measurements, inspiration and accountability.
Robert has been a trainer at Five Seasons Family Sports Club in Cincinnati for three years and works on improving performance, whether in a sport or daily life. He has clients with diverse needs from those wishing to become better athletes to those recovering from surgeries. He also focuses on prevention and management of chronic conditions. He received his MPH in Health Education and Health Promotion and BS in Sports and Biomechanics from the University of Cincinnati. He is an NCHEC Certified Health Education Specialist and an ACSM Health Fitness Specialist.