Lounge
Why you need to ditch BMI for better ways to assess your health
Summary
BMI or Body Mass Index used to be a standard way to measure health and fitness. Learn why this is now outdated and the better measurements that have replaced it
There used to be a time when upon joining a gym, the first thing trainers would make you do would be to stand on a BMI (body mass index) machine, enter your height and weight, and wait while it whirred and spat out a receipt with your number.
While BMI is basically a value derived from the mass (weight) and height of a person, the machine would also give data on visceral fat, real age and other determinants that could either be impressive or scary or both. But over the past two or three years, especially with new research shedding light on the drawbacks of BMI, the machines have vanished from the gyms, and hardly anyone is talking about the metric.
The BMI metre, which asks for age, height and weight, is measured in kg/m². Anything less than 18.5 is underweight, from 18.5 to 25 is normal, 25 to 30 is overweight and anything above that is marked as obesity. For the longest time, my BMI would be below the required level (less than 18.5), which always translated to “eat more, lift heavy". This is not to say the strategy was incorrect, but BMI was just half the story pretending to be the full.
Also Read Get more out of your pull-ups with these 4 variations
“A person with lots of muscle and minimal body fat can have the same BMI as a person with obesity who has much less muscle. BMI also varies (because average body fatness varies) among people of different ages and whether they are active or sedentary. That means it can be misleading in some cases. For instance, an athlete with much more muscle than fat can have a BMI in the overweight range," states a Yale Medicine article titled, Why You Shouldn’t Rely On BMI Alone.
Even more concerning was the fact that the BMI tech is practically ancient, invented in the 1800s by Belgian mathematician and sociologist Adolphe Quetelet as a means to find out the ‘ideal average man’. He never intended it to be used as a fitness metric. “In developing his index, Quetelet had no interest in obesity. His concern was defining the characteristics of ‘normal man’ and fitting the distribution around the norm," states a journal article in the Oxford Academic titled, Adolphe Quetelet (1796–1874)—The Average Man And Indices Of Obesity.
Also Read Should you exercise on an empty stomach?
“The quest for a practical index of relative body weight that began shortly after actuaries reported the increased mortality of their overweight policyholders culminated after World War II," adds the article. And this is what led to BMI being used as a measure of fitness.
Which is not to say that BMI values are entirely useless, just that it is not the sole marker of health. There are other technologies with better data that can tell you more about your body.
“A body composition machine is more accurate, along with waist-circumference indices," says Goa-based physiotherapist Aaron Rodrigues. Rodrigues also specialises in working with athletes. “These will tell you fat percentage, bone weight, type of fat in the body and other markers which will point you in the right direction when it comes to planning your fitness journey."
Also Read 3 great fitness hacks for a quick and effective workout
Rodrigues says that the fitness community was baffled when people with healthy BMIs were also getting diabetes and cardiac issues. “Waist-circumference indices were superior to BMI when explaining/predicting our CMR factors, before and after controlling for age, sex and ethnicity. No single WC (waist-circumference) index was consistently superior," states a study titled BMI Is Dead; Long Live Waist-Circumference Indices: But Which Index Should We Choose To Predict Cardio-Metabolic Risk?This conclusion points once again to the erratic nature of predicting cardiac health.
WC index is basically a waist-to-hip ratio, in which you use a tape, not too tightly while breathing out normally to take the measurement. “The measurement is taken from the point of your lowest rib to the top of the hip bone," says Rodrigues.
“Men and women with WC values ≤102 and ≤88 cm, respectively, were considered to have a normal WC, whereas men and women with WC values >102 and >88 cm, respectively, were considered to have a high WC," states a study published in the The American Journal Of Clinical Nutrition, titled, Waist Circumference And Not Body Mass Index Explains Obesity-Related Health Risk.
Also Read 5 great compound exercises that build strength and burn fat
All of these indexes have an unknown variability. There are no guarantees. When it comes to working out, the main goals remain the same: eat as healthy as possible with room to enjoy cheat meals, lift weights and use resistance, and get a sweat going with some movement or cardio activity.
“If you are still interested in knowing fitness variables, there are options like manual muscle testing where five grades of strength can be found with gravity, and against gravity and resistance. But that happens at higher levels of athletic performance," says Rodrigues. Until then, maintain a logbook with how far you have come in terms of lifting weights, and calculate your heart variance using a fitness watch. When it comes to cardiac health risks, checking your full body composition at a clinic is the best way forward.
Pulasta Dhar is a football commentator, podcaster and writer.
Also Read How to ace the fat-burning, muscle-building dumbbell snatch
