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>> After discussing energy balance, we need to talk
about weight management.
Weight management is something we probably only
to understand a bit more even as a nation because there is
such a growth in over weightedness.
If we look back to the early '90s to the mid 2005,
we see the spread of over weightedness
from just a few states back in 1990 to all states except
for a few of the east coast states and Colorado.
So if you want to go to a place that has more lean people,
that's where you wanna go.
What is the problem with being overweight?
Well there's a lot of problems.
There is the link to heart disease and stroke.
There is such a strong link that we're learning more and more
about to type 2 diabetes.
Cancer-- some forms of cancer, uterine, gal bladder, cervices,
ovarian, breast and colon cancers and prostate in the men.
The individual who is overweight may suffer also
from sleep apnea, that carrying around all
that extra weight could be *** the joint so osteoarthritis,
gal bladder disease and gal stones may also be prevalent,
problems with the liver.
Now this are all physiological outcomes,
there is also social consequences, you know it's a--
it can be rough on individuals in social settings.
And then psychological problems, which I think is probably one
of the most important outcomes of being overweight.
People may not reach their full potential.
They restrict themselves on what they do because of their weight
which really shouldn't happen.
So question is why are people overweight?
There is not one reason.
It is multifactorial.
So we have to say genetics,
definitely genetics does play a role.
We see that when we look at the parents.
If both parents are obese then the child has an 80
percent chance.
If one parent is obese, it's a 40 percent chance.
If neither parent is obese then the child has a 10
percent chance.
They have been identical twin studies, identical twins tend
to be the same weight even if they are reared apart.
And we see that in adoptive children tend
to be similar weight to their biological parents.
Genes probably putting us
in a vulnerable position without weight.
Genes may make a person susceptible to obesity.
There is also physiological factors in looking
at fat cell development.
When more energy is consumed than is expended then
that excess energy will have to be stored in fat cells.
When we increase the number of fat cells
that is considered hyperplastic obesity.
Or we can increase the size of the fat cells
which is hypotrophic obesity.
There are definite periods in our life
where we increase the number of hyperplastic
in the first two years of infancy.
During adolescents, we are increasing
in the number of fat cells.
And once we have a fat cell, we have it forever.
We then once we have the fat cell,
we can increase the size of it.
So if there's excess energy,
it will be stored in those fat cells.
Now we're thinking even as adults
that we actually once we feel fat cells
and they can be filled three to five times their size.
But if we fill them, they do tend to split.
And we now increase the number.
So fat cell development is physiological.
What about metabolism is another factor.
Some people believe that there is a set point theory
to our weight.
That is the body tends to maintain a certain weight
by means of its own internal controls.
Maybe there is such a thing as a weight thermostat just
like there is a blood glucose control.
There is blood volume control
so maybe there is a weight thermostat.
Also when we look at metabolism we have
to also appreciate the enzyme that's involved
in promoting fat storage.
That is called lipoprotein lipase, LPL.
Lipoprotein lipase promotes fat storage and it tends to run
with obese people tend to have more LPL.
Also LPL is impacted by gender specific hormones like estrogen.
Metabolism, set point theory and fat cell enzymes.
There is also hormonal factors.
There are the gender specific hormones, estrogen
and testosterone that can impact our weight control.
There is thyroxin from the thyroid gland
that influences our metabolism.
And then there are the proteins that act as hormones
and they act on the hypothalamus.
There is leptin.
Leptin is the satiety hormone.
Comes from fat cells goes
to they hypothalamus to say "We're full.
We don't need to re-feed."
Then there's ghrelin from stomach cells that can be--
ghrelin can be called hunger hormone.
And is true isn't it, when you're think
of your stomach growls when it is hungry,
so ghrelin, the hunger hormone.
Ghrelin promotes positive energy balance
because it stimulates the appetite
and decreases our energy expenditure.
Leptin is a good guy.
Ghrelin is the bad guy.
There is an interesting relationship
between leptin and ghrelin.
As we discover more and more, the connection of diabetes
and over wieghtedness and put them in a modern day context.
We see that a lot of people sleep deprived
and many people are overweight.
Its-- Are they linked, always see that a lack
of sleep increases ghrelin which is the hunger hormone.
And it decreases leptin which is the satiety hormone.
So maybe a lack of sleep lifestyle has
to be a reason why we're obese.
Because it impacts our hormones.
There are also social cultural factors.
Develop societies tend to have a high level of fat.
Your age, young adults' higher incidents of obesity.
The gender, women more so than men.
Your race, African-American, Hispanics, Native Americans,
Pacific Islander tend to be ethnic group
that is more prone to obesity.
Your income more prevalent obesity is more prevalent
in lower income.
Educational level is really quite a strong factor.
The less educated you are, the higher the incidents of obesity.
Your occupation, if you have a less prestigious job,
there is higher incidents of obesity.