BMI stands for Body Mass Index, it gives you an indication if your weight is healthy compared to your height. It’s really easy to calculate as it only uses your body mass (in kilograms), divided by your height (in metres squared). It doesn’t take into account age and gender, except for young people under 18. If maths is not your thing and you want to know what your BMI is, just type “BMI Calculator” on your search bar and you’ll be spoilt for choice. An adult is considered healthy if their BMI is between 18.5 and 24.9, underweight if it’s under 18.5, overweight above 24.9 and in the obese range above 30. Now, I’m sure most of you already know this, but I would like to have a closer look at why you shouldn’t rely on it by itself.
Update on my own weight loss journey
I started to write about my weight loss journey in one of my very first posts on this blog. By then I was at 78 kg and had already lost 7 kg. Since this post, I’ve carried on with my new healthy lifestyle and I am today near 68 kg, which means I lost another 10 kg. In terms of BMI, I went down from the obese range to just overweight and I’m now on the verge on being back to healthy. Hallelujah. I’m 165 cm tall so a healthy range for me means between 50 kg and 68 kg. I was aiming at 60 kg (in the middle) to have some sort of exact number in mind but I know by experience I’m starting to look very skinny under 60 kg, so that would actually be my absolute minimum! What would still be considered “healthy” for me (between 50 kg and 60 kg) would probably look underweight as I would start worrying people around me. That’s why I say BMI is a great tool to give some sort of indication but no one knows your body better than you.
BMI by itself has its limits
If BMI only uses people’s height and weight to indicate their healthy range, you can see why it would have its limits. It cannot tell the difference between excess fat, muscle or bone. Even though the range is quite big to take into account natural variations in body shape, some athletes with a high muscle mass could easily be within an overweight or obese category while they’re actually very healthy. Ethnicity also matters: according to the NHS, Black, Asian and other minority ethnic groups have a higher risk of developing some long-term conditions (such as type 2 diabetes) with a BMI above 23, so even if they’re within the healthy range (which is between 18.5 and 24.9). Pregnant women should obviously not use BMI as an indicator as it wouldn’t be accurate either.
What other metrics should you watch out for?
If BMI is pretty straight forward to tell you if you weight too much (or not enough), it won’t tell you if you have too much fat. Ultimately, that’s what you want to focus on because that’s what puts you at greater risk of developing chronic diseases such as type 2 diabetes, heart attack, stroke or even cancer. Basically, you can have a healthy BMI and still carry too much fat around your stomach. One way of finding out would be to invest in a smart scale that will give you more detailed information about your body composition. Another one is to take measurements of your waist size to check if you need to lose dangerous fat. Regardless of your BMI, you should try to lose weight if your waist size is more than 80 cm (for women) or 94 cm (for men). This is not easy but necessary, my waist size was 92 cm for a weight at 85 kg back in August. More than 4 months later, I lost 17 kg and 13 cm around the waist. I am now only starting to be healthy in that area too with a waist size at 79 cm, which translates into significantly less risk of developing a long-term disease.
The bottom line
In conclusion, I would say BMI gives a good indication about how healthy you are, but only if it is used in combination with other factors. If you’re way above or under the healthy BMI range, you should definitely act. But don’t necessarily aim to be right in the middle to have the perfect body, as everyone has a different body shape that doesn’t always reflect their weight. If I’m aiming at 60 kg now, I know my weight will increase again when I focus on toning up because my muscle mass will increase, which is heavier than fat. By then, I’ll replace my objective with a more appropriate one! I can tell you I already feel the positive impact this journey is having on me. I hope January will see more people making good (and lasting) healthy resolutions.
Do you consider being the best version of yourself already or do you need to make a change?
Big Girl x