Fitness, Nutrition

Why BMI is Bogus

The Body Mass Index has been around a long time. It’s still the number one tool physicians use to determine whether patients are at a healthy weight. This is a problem. Because it’s not accurate! It’s a 200-year-old mathematical formula created for a specific purpose. Since then, its use has been called into question as studies show it’s not the best way to measure body size.

A Belgian named Lambert Adolphe Jacques Quetelet created the BMI formula in the early 19th century. He was a mathematician, not a physician. He produced the formula to give a quick and easy way to measure the degree of obesity of the general population to assist the government in allocating resources. It wasn’t tested and fails to account for waist size, bone structure, muscle mass, and more.

This is a huge problem because often insurance companies will charge more for someone who has a higher BMI, even though that person could be a healthy, fit individual who happens to carry a lot more muscle on their frame. It’s also not helpful for smaller individuals whose health markers are all positive; they just happen to be petite.

So, what should we use to determine obesity? Waist to height ratio is emerging as one of the best ways and it’s an easy formula. All you need to do is measure your waist, just below your belly button. Divide that number (in centimeters) by your height (also in centimeters) and voila! Women want a number below .49 and men below .52. Basically, you want your waist to be no more than half your height.

Ditch the Scale

You may be wondering how weight fits into this. Well, it’s complicated. Your weight is determined by your muscle mass and fat mass. People who have more muscle weigh more because, well, muscle weighs more. Women also have a challenging time tracking weight due to the the fluctuations in their weight caused by hormones and the menstrual cycle. Plus, just because you thought you looked hot in your 20s when you weighed 130 pounds doesn’t mean you’ll look hot today at that same weight. Bodies change, muscle mass decreases with age and that 130 might not be healthy for you anymore.


I recommend the following, if you are trying to determine a healthy weight for yourself.

  1. Calculate your waist to height ratio. If it’s high, you know you need to lose a few pounds.
  2. Weigh yourself on a scale that also shows body fat percentage. While that number may not be entirely accurate, it will show trend over time and help you determine if your interventions (e.g. building muscle, eating fewer calories) are moving the body fat percentage down, and the lean mass up.
  3. Take a photo of yourself from the front, side, and back. This is your “before.” Every four weeks, take the same photos again, preferably with the same clothing on. See if you look different.
  4. Pay attention to how your clothes fit. Are they looser? Fitting differently around the lower body? These are indicators of shape changing or muscle being added and fat being lost in all the right places.

Achieving and/or maintaining a healthy weight requires consistent exercise and healthy nutrition. If you need help in either or both of these areas, drop your name and email below! I’m happy to help!

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