February 18, 2016 1120
But first: What is the BMI?
The Body-Mass-Index is a value derived from the mass (weight) and height of an individual. It is defined as the body mass divided by the square of the body height, and is universally expressed in units of kg/m². The BMI is supposed to show whether an individual is underweight, normal weight, overweight or obese based on the amount of tissue mass consisting muscles, fat and bones. At this stage I was about to insert a link for you to calculate your own BMI. But like you can see, I didn´t. You will find out why if you continue reading.
BMI Chart Recommendations
Like you can see in this chart there are BMI recommendations depending on Height and Weight. The first weak point of this chart is quite obvious. It does not consider the age and the sex of the individual. So can we compare the BMI of a 20 years’ old man with the BMI of a 70 years’ woman? I really don’t think so. And I´m sure, you agree.
But let´s assume we compare two individuals with the same weight, height, age and sex. Both are 25 years old, male, around 90kg heavy and 189cm tall. According to most of the BMI calculators I found online, the result of both of them has to be the same - A Body-Mass-Index of 25.2. But what if one of them is a complete couch potato with less muscles in his upper body but a quite corpulent bum whereas the other one is kind of an athlete who is good in shape? Both of them may weigh the same and also can have the same BMI because the distribution of fat and muscles is totally different. Tell me if I´m wrong but is that comparable?
For years different studies told us that people with a BMI between 20-25, what is equivalent to normal weight, are the healthiest and live the longest. But actually, a new study of the National Centre for Health Statistics in the USA came to the result that people with a BMI higher than 25 but lower than 30 have a higher probability to live even longer. Remember, a BMI of more than 25 tells us to be overweight. Does that mean overweight is healthier than being normal weight? This is another point that does not really make sense to me in this case.
What I can say for sure is that the simple number of the BMI is definitely not an evidence for a healthiness. Even though it says you are. There are many other factors we have to take into account. People who smoke a lot are likely to weigh less than people who do not. But even if that can lead to a lower BMI, it can be the cause for lots of other diseases.
Furthermore, the pace of the metabolic processes of an individual plays an important role for its weight. A person with a fast metabolism can be lighter than another one although he is eating nothing but junk food.
All in all, I don´t want to say the BMI is a completely useless value. It does give a good first impression about a person’s relation of height and weight and can be an indicator for obesity and anorexia. But in my opinion, that’s all. At the end of the day, if I trust my BMI, the value tells me to be overweight. And that can´t be true! :) How about you guys? Let me know in the comments whether you agree or disagree to this!
by Jens Behrensen
German fitness addict sharing my experience and trying to bring a healthier lifestyle to people. View all articles by Jens Behrensen.