Energy Balance - 3/3


Uploaded by eLearningCentralia on 04.03.2010

Transcript:
And that you do it for --
and you can approximate how many calories you spend
with exercise.
Next question for the teeter-totter approach is,
"Am I at the correct weight?"
Well, what we do is we say, "Let's use BMI."
BMI is body mass index, and body mass index is a method
to say what you should weigh depends on your height
and definitely what you weigh depends
on if you have any health conditions.
So how do we calculate BMI?
What we do is we take weight in kilograms and divided it
by our height in meters squared.
So if we are 5 foot 5 and we weigh 125 pounds,
125 pounds converted to kilograms is
like 56.8 kilograms, 5 foot 5 is 1.65 meters.
To square 1.65 meters, you multiply it by itself,
and you will get 2.72.
Divide 2.72 into 56.8 kilograms, you will get 20.88.
Now, my question is, is our 5 foot 5,
125 pound-individual at a healthy weight?
At 20.88, BMI is between the healthy range.
So, yes, they are fine.
So lesson 18 and a half is underweight, between 18.5
to 24.9 is healthy, between 25
to 29.9 is considered overweight, and anything
over 30 is considered obese.
Now, this is not a perfect system.
People can have a lot of muscle mass,
and so therefore they're going to weigh more,
and they will come out appearing to be either overweight
or obese, and they will be concerned
and they will be trying to obtain something
that they already have, which is a healthy weight.
So it's not perfect.
One way to overcome this imperfection is
to know how much fat is on the body.
There is certainly fat mass and lean mass,
and lean mass is mostly muscle, bone and organs,
all the stuff you got to have.
But what about fat?
We all need some fat.
Some fat is essential.
In the man, essential fat could be about 3 to 5%,
in the woman essential fat would be about 12%.
On top of essential fat, there is storage fat,
and that's the problem fat.
If we store too much fat, it will not be necessary
like essential fat is, and most men
and women have similar amounts of storage fat,
probably about 12 to 15% is adequate.
So in an athletic person 5 to 10%,
12% is a healthy amount of fat.
In a athletic female, anywhere from 15
to 20% is an adequate amount of fat.
How do you know how much fat you have?
They are measurements of body composition.
There's the pinch test, the skinfold test,
there is the weighing and water.
You know, if you float, that might mean that you've got a bit
of fat, there is the bioelectrical impedance
measurement, they are the two very fancy new latest
measurements where air displacement is measured,
and then there is an x-ray measurements.
The x-ray, DEXA.
Can be used also not only measure body fat,
but also to measure bone density.
So you could get two things out of that test.
The gold standard typically is water weighing
and the bioelectrical impedance tends to be as easy or as close
to the gold standard of water weight.
But you will find a number that will tell you how much
of your total weight is fat, and you could use data management
in addition to your BMI to give you an idea
of your healthy weight.
In healthy weighted people, some fat is certainly stored
around the organs of the abdomen,
but what we're concerned with these days is a lot
of overweight people are storing an access amount
of abdominal fat, and that excessive amount does increase
the risk for a variety of diseases.
High blood pressure, diabetes, heart disease, stroke.
So maybe it's more not just how much fat you have on the body,
but where your fat is stored.
So you could do a BMI, you could do a body composition test,
but you could also do a waist circumference measurement test.
If you have a higher amount of fat in the abdominal section,
that could be by a waist circumference.
So if you have a tape measure, you can do this easily enough.
In the male, a waist measurement
over 40 inches would be considered a high risk
for those chronic diseases, the heart disease, stroke,
the diabetes, the hypertension and some types of cancer.
In the female, if the waist circumference is more
than 35 inches, that is associated with higher incidence
of those chronic diseases.
We always talk in terms of body shape, the apples and the pears.
In the male, when the gain weight they typically gain it
in their upper body, and that tends to show with a large waist
and a dangerous predisposition to problems.
Now, women typically are pears, not that women like being pear
as much as they should, but pears are protective.
That particular shape does tend to have a lower incidence
of these chronic health problems.
So it would be a good idea for you at the end of this chapter
to do your EER the hard way or the easy way,
find out what your BMI is
and do a waist circumference measurement test because all
that is enabling you to know more about where you are
with your weight, and if you go back to the teeter-totter,
energy in and energy out.
If you aren't at a healthy weight, then you're going
to have to think about, "How can I either reduce the amount
of calories in or spend more calories out?"
One pound of fat is 3,500 calories,
and you don't lose one pound of fat in one day.
Ideally, you loose one pound of fat,
maybe two pounds in a week that's it.
So roughly, you've either got to do something
with 500 calories per day, by the end of the week,
you've lost your 3,500 calories or reduced them
and maybe you've lost a pound.
And losing a pound is a success.