If you are somebody who has been told
that you need to lose 20 or 30kgs
and if you want to improve your diabetes
you need to completely change your exercise and activity levels
you may not have been told
what you need know.
And if you watch this short video
it will all become clear.
I just wanted to spend
a little bit of time explaining
this concept of the Body Mass Index
and the 'ideal body weight',
so that you better understand
how achievable
really quite significant success is.
So the first thing is
about Body Mass Index
BMI
and simply
it is a measure of your weight, in kilograms
divided by your height, in metres
and for mathematical reasons
they square the height.
So if I weighed 60kg
and I was 1.5m in height,
then it would be 60kg over 1.5 x 1.5
and that would give me my BMI.
And the normal reference range,
or what we call the normal range,
is based on clinical studies
that tracked the risk of somebody
developing a complication
and compared the risk to the Body Mass Index
and if I draw this
this is what we call a J shaped curve
because actually if you are too thin
it is not good,
people who are very thin
often have higher rates
of risk of developing problems
and then as the weight goes up
there is an exponential increase in risk
that occurs as your BMI goes up.
But there is a little spot, right down the bottom,
where the risk is at its lowest
and that is how we define
the normal reference range
and for most people that is between 20-25.
And so that is when we talk about
idea body weight
it is ideal because it has the lowest rate of risk
for things going wrong
so we think that is the most positive
place to be.
But what happens to people who are
significantly overweight?
Perhaps their BMI is 30,
so that is the definition of obese,
or 35 or 40
and if you start to plot that group of people
you can see that the risk
becomes incredibly high
for certain people
and the higher your Body Mass Index is
the greater the risk.
So people for example
with a BMI of 40
have a risk that is really incredibly challenging.
But the other interesting thing is
that if you can reduce your Body Mass Index
from say 40
down to 35
that is a substantial risk reduction.
And if you can reduce it from 35 down to 30
that is still a substantial risk reduction
but not as big as the person
that has reduced their weight from a BMI of 40
down to 35.
And if you go from 30 to 25
again there is further risk reduction
but it is not as substantial.
So whilst we talk to people about
their ideal body weight
and if they weigh 100kgs
perhaps their ideal body weight
might be 70kgs,
in fact changing from 100 down to 90
has a profound effect
because a person literally slides down
the BMI curve.
And in doing so has a
massive risk reduction.
So the trick with weight loss
is not to think about what your ideal body weight is
because that actually
may be very difficult to achieve
particularly if you are 30, 40, 50kgs
above what you should be.
The trick with weight reduction is to understand
the benefits that you get
by making small modest changes.
And just if we look at something like diabetes
if a person is able to lose about 10%
of their body weight
so if you weigh 110kgs
then you are looking at 11kgs,
that has a profound impact
on how well your insulin works
on your glucose control,
and your cholesterol
and your blood pressure.
It is not about achieving perfection.
It is about reducing risk as quickly
and as effectively as possible
in the most achievable way.