If you could wave a magic wand so you would weigh the same, but have less fat, would you do it? Of course you would, very few people wouldn't.
What about if you could wave a magic wand that would make you lose weight, but have more fat, would you do that? Of course not! No healthy person would.
Regardless of what we are told, no one, or at least no normal person, wants to lose 'weight'. What people actually want is to lose 'fat'.
Being overfat causes a huge number of illnesses for individuals, and is a massive burden on society. Being overfat, regardless of your weight, is unhealthy. Similarly being under fat, regardless of your weight, is also extremely unhealthy.
For some time I have kept an eye on my weight. Mostly because my weight kept getting too low, which was worrying.
As well as keeping track of my weight in kilograms, I have kept an eye on my Body Mass Index (BMI). BMI is a better metric than just weight, but it's not perfect.
I wondered if knowing my percentage of body fat would be useful. Recently I measured my neck, hips, waist etc. I entered these numbers along with my height and weight into a few online calculators that are meant to estimate my percentage of body fat. Even though I entered exactly the same numbers, the results from different calculators were vastly different.
Depending on the calculator I used, my body fat estimate came back as low as 5.5% (which is drastically low and close to death) up to a far healthier 10.8%. To give these numbers some perspective, the 'Healthy' range of body fat for a male of my age is 11% to 20% body fat.
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| image from https://commons.wikimedia.org/wiki/File:Cells_of_the_human_body_by_mass.svg |
My results from various online body fat calculators:
https://www.precisionnutrition.com/body-fat-calculator
My result: 10.8%
This US Navy body fat calculator https://www.omnicalculator.com/health/navy-body-fat
My result: 6%
A different navy calculator https://www.bizcalcs.com/body-fat-navy/
My result: 9%
The US Army body fat calculator https://www.omnicalculator.com/health/army-body-fat
My result: 5.5%
You may be asking yourself, if I entered exactly the same data into different calculators how can the results vary this much. The answer is simple: online body fat calculators are not accurate!
If you want a number that will either make you feel good or make you feel bad, then use online body fat calculators. When you get a result that you don't like, look around, sooner or later you will find a body fat calculator that gives the result you are after. This sounds pointless, probably because it is pointless.
Instead of measurements and online calculators, you could try to use skin fold calipers. These are meant to be reasonably accurate at estimating subcutaneous fat (ie fat under the skin) if used correctly. They do not measure or estimate visceral fat (ie much more dangerous fat around the organs). If you are skinny fat, you will have little subcutaneous fat, and a higher amount of visceral fat. For most people, fat calipers are probably somewhat useful and relatively accurate. For skinny fat people, these calipers are not very useful.
Another way to estimate your body fat is to use body fat scales. I have never used them, but everything I read says that they are ragingly inaccurate.
If you want a true measure of your body fat, you would need to do a water displacement test, or a Dual-Energy X-Ray Absorptiometry scan, or even use an Air-Displacement Plethysmography pod (and even then I am not sure how accurate this last one is).
If (like me) you lack the money or ability to access to these tests, then stick with BMI. While BMI is far from perfect, it is better than just using raw weight, and you can measure this at home for free. All you need are bathroom scales.