- Hello, I'm Philip from Body Scan.
If you're thinking of having a DEXA body scan,
I'll bet my bottom dollar that one of the main reasons
you want a scan is to get an accurate figure
for your body fat percentage.
Well today, I'm going to be a bit controversial,
overturn years of received wisdom
and show you that while you definitely should have
a DEXA Scan, body fat percentage is NOT the best number
for measuring your fat.
First let's quickly dispense with the limitations of weight
and body mass index, or BMI.
When it comes to weight, a kilo is a kilo is a kilo.
So two people can have the same weight,
but have very different body compositions.
One could be 70 kilograms of fat,
the other 70 kilograms of muscle.
But if a scale says they weigh the same,
then it's not telling us anything
about their body composition.
Now BMI (or body mass index) is a small step up from weight
because it takes your height into account.
And that's valid because we would all expect
someone who's seven feet tall to have more fat and muscle
than a person who's five feet tall.
But the problem with BMI is it is still
based on your weight.
So if those two people of 70 kilograms happened to be
the same height, then their BMIs would be the same too.
And we'd be no wiser about their levels of fat and muscle.
So then we come to body fat percentage and that's what
nearly everyone who comes to Bodyscan wants to know.
It's the figure used in men's and women's magazines,
it's used by personal trainers.
It's the output of every measurement method -
the fat scales you can get from Argos, skinfold calipers,
Bod Pod, underwater weighing, and the bioimpedance machines
you see in gyms and Boots the chemist.
They all give you a number called 'body fat percentage'.
Now it's definitely a better number than weight or BMI
because it tells you what proportion of you is fat.
But there are two problems with body fat percentage.
The first is that, just like weight and BMI,
it is a single number that is rolling up both major elements
of body composition - fat and muscle - into that one number,
meaning it will change not just with a change in fat,
but also with a change in muscle.
The second drawback is this:
Imagine two people who are both 25% body fat,
they're the same, right? Well, no, because if one of them
weighs 80 kilos, being a quarter body fat means
they carry 20 kilos of fat.
If the other person weighs a hundred kilos,
then 25% fat means they carry 25 kilos.
Two people with identical body fat percentages carrying
different amounts of fat.
Ah, but you say the heavier person is probably taller,
so of course they carry more fat.
Well maybe, and maybe not. And if they are, how much taller
would they have to be for the comparison to be fair?
four inches, six, ten?
That's the problem with body fat percentage.
It doesn't allow for height, which is a key
factor affecting the amount of fat and muscle you carry.
So now I'm going to introduce a key differentiator that
a DEXA body scan gives you and it's one of many.
Because DEXA measures your fat and lean mass separately,
we can overcome the limitations of body fat percentage by
giving you two numbers.
One number for fat, that's unaffected by muscle
and one number for muscle that's unaffected by fat.
These two numbers are known as your Fat Mass Index
and Lean Mass Index.
And they tell us how much fat you carry for your height and
how much muscle you have for your height.
Let's look at a real life example to show why FMI and LMI
are much, much better numbers than body fat percentage
for understanding your body composition
and setting your priorities.
These two men who both had a DEXA scan at Bodyscan are
exactly 21.5% body fat.
And comparing that result to all the men we've ever scanned,
that result is just about average,
pretty much right in the middle.
So if we use body fat percentage as the
ultimate measure of fatness, we would say that they are both
average and therefore have some room for improvement.
But when we look at their fat mass and lean mass, and take
into account their height, we get a very different picture.
One does very well for fat, he's in the lowest 25%.
Whereas the other is in the worst 25%.
But it's when we come to muscle
that we really see the difference.
The low fat guy is in the bottom 5% for muscle mass,
less muscle for his height than 95% of all the men his age,
whilst the other is in the highest 5%!
He has the kind of muscle a pro bodybuilder would have.
And that highlights a particular problem with
body fat percentage. If you have good muscle,
it will push your body fat percentage down and give you
a very misleading picture of how much fat you have.
So whilst these two guys have the same body fat percentage,
their priorities are polar opposites.
One needs to gain muscle. The other needs to lose fat.
And that's why body fat percentage is not the best number
for measuring your fat.
Now, if you're worried you can't get your head around
these new numbers and you don't know what they should be,
what's high and what's low,
you can relax because we will do all of that for you,
thanks to our huge database of DEXA body scans.
It's the biggest in the UK.
Only Bodyscan can utilise the advantage
of your fat and lean mass indices because nobody
else in the UK has enough data to make a valid comparison.
Here is that data condensed into two tables.
When it comes to fat, the table at the top,
you really want your fat mass index to be down the at the left side
of the table in the lower percentiles.
If we're looking to increase muscle mass,
the table at the bottom,
you'll want to see your lean mass index move to the right.
A bodybuilder will be up here.
If your numbers are not where you want them to be,
we will leverage FMI and LMI to suggest realistic short-term
and long-term targets in order to reach your goal.
We'll then put those into our Bodyscan calculator
to translate them into actual kilograms of fat and muscle
and then work out how many calories you need to eat
and how long it will take to get there.
So there are two key takeaways today.
Number 1: because we focus on fat and lean mass
as separate components of body composition,
we can move beyond weight and body mass index.
Remember, the scales tell you nothing about
body composition.
They just tell you your relationship with gravity.
Number 2:
because Bodyscan has the biggest database of DEXA scans
in the UK, we can move beyond even body fat percentage,
which we've seen has its own limitations
and we can utilise the best measures of fat and muscle,
your fat mass index and lean mass index.
So for the very best measure of your body composition,
for specific realistic targets for fat loss and muscle gain,
to learn how to reach your targets
and how long it will take you, book a scan with Bodyscan.
I promise you - you'll be blown away!
Thank you for listening and we'll see you soon. Bye bye!