BMI Inaccuracy’s

Body Mass Index (BMI):

Is your weight divided by the square of your height.

This photo (below) shows just how different women that weigh the same can be.  BMI was developed in the mid 1800’s.  150 years ago people were a lot smaller (look at the height of doors on old churches). 150 years ago people had completely different diets, exercise regimes aend occupations.  Comparing us on a height/weight scale to someone from 150 years ago is extremely inaccurate to me.  We are taller, better nourished and arguably have more muscle than our ancestors. 

BMI women 150lbs


A Scandinavian man will be much taller than an Asian man, both could be of healthy weight and fat levels but BMI ratings will make no distinction between them, does that seem in any way accurate?  A woman with a slim waist and big boobs could have an overweight BMI but have very low body fat. Brian O’Driscoll has an overweight BMI, is he overweight?  In my opinion BMI is extremely inaccurate for most people and cringe when someone in the industry mentions it.

Body Fat % combined with waist, hip, chest measurements etc… is a much more accurate way to measure whether someone is in shape or not. However, if you have an obese Body Fat % you will also have an obese BMI rating, but for most of the population BMI will give an inaccurate rating.

BMI Chart

Most obesity epidemic studies are bases on BMI readings.  Does this mean there is no epidemic?  No, the figures are getting worse, it just means they’re measuring it on an inaccurate scale.  The scale might be wrong but the figures are getting worse for sure.

BMI is a lazy, very outdated and unprofessional way to measure someone’s health.  Next time someone mentions BMI, especially if it’s your doctor, don’t be afraid to question it and ask them to measure your body fat % instead.


author: Andy Kenny