Dietary Fat: The Good, The Bad,
and the Ugly
A Few Fat Facts
• Chemical family name
for fats and related
compounds is lipids
• Word lipos = Greek
word for fat
• Fats are very high
energy nutrients
Do Any of these look good?
"We’re hardwired to hunger for fatty, sugary,
salty foods because, back when our
ancestors were foraging for every meal,
palatable eats meant extra energy and a
leg-up on survival."
Dr. David A. Kessler, author of The End of Overeating: Taking Control
of the Insatiable American Appetite
How Your Body Uses Fat
Visible Body Fat:
• Source of stored
energy
• Gives body shape
• Cushion (need some
fat on your buttocks to
sit!)
• Reduces heat loss
(insulation blanket)
Your Body Also Uses Fat
Kind of like bubble wrap for your guts!
Invisible (internal)
body fat:
• Part of every cell
including neurons
• Shock absorber to
protect internal
organs
• Part of hormones and
other biochemicals
How does our body get energy
from fat?
Well, picture a chain of long balloons…
When you drop a balloon into water
It floats! That’s exactly what happens when
you swallow fat-rich foods.
The fat floats on top of the watery food-andliquid mixture in the stomach.
Okay…not related…but isn’t that a
really FAT cat?!!
Back on topic…Since the fat floats
This limits the effect that
fat-busting digestive
enzymes can have on
it.
Because fat is digested
more slowly, you feel
fuller longer after
eating high fat meals.
After a meal like one of
these, you might say: “I
feel full…way too
full…urp!”
Break it down…
When fat moves down your digestive tract
into your small intestine, a hormone
signals your gallblader to release
BILE
Bile is an emulsifier, a substance that allows
fat to mix with water.
Fatty Acids
The bile helps to break down the fat into
fatty acids.
These can be used as a source of energy
Our body prefers using carbohydrates (since
glucose is easier and more efficient) and
will only burn fat when other available
energy sources have been used up.
How Much Fat is Too Much?
Too much fat = increased risk of obesity,
diabetes, heart disease and some forms of
cancer (especially colon cancer)
But what about too little?
Infants and children
need fat to thrive.
Everyone needs some fat to absorb fatsoluble vitamins that smooth the skin,
protect vision, bolster the immune system,
and keep reproductive organs functioning.
No More than…
In 2005, Dietary Guidelines for Americans
recommends no more than 20% to 30% of
total calories from fat.
For a diet of 2000 calories per day, that =
400 to 600 calories
.
But are all fats equal?
No…and it all comes
down to chemistry.
Fatty acids are the
building blocks of fats.
A fatty acid is a chain of
carbon atoms with
hydrogen atoms
attached to the
carbon.
But what does that have to do with
what kind of fat I should eat?
The more hydrogen
atoms, the more
saturated the fatty
acid.
Saturated, unsaturated,
or trans fat all have
different types of fatty
acids.
“EEK!! I still want to know what
does this have to do with me
and my food choices?!!”
Saturated Fat
Appears as a "waxy" or
solid fat at room
temperature.
What would it look like
on your inside as it
contributes to the fatty
cholesterol build-up
inside your arteries?
Sources of Saturated Fat
• Beef, veal, lamb, pork and poultry.
• Lard, butter, whole milk, cheese
• Tropical cooking oils such as palm and
coconut.
Should I eat this?
You can have some saturated in your diet,
but aim to limit this fat to seven percent
(preferably less) of your total daily
calories.
Unsaturated Fats
• Heart healthy fat that when used in place
of saturated fat has the potential to lower
the bad cholesterol known as LDL.
• It is usually in a liquid form at room
temperature and when chilled.
Why Unsaturated Fat is Good
• Unsaturated fat contains "essential" fatty
acids needed by our bodies to make
hormones and to ensure healthy cell
structure.
• Contains omega-3 and omega-6 fatty
acids, and is helpful to the heart, brain and
other body systems.
Foods that have Unsaturated Fat
• Seafood
• Cooking oils such as vegetable, safflower,
cottonseed and corn.
• Salmon, herring, and other fish
• Walnuts, sunflower seeds and flaxseeds.
Unsaturated fat is good, but…
• It still has calories.
• Aim for 10 percent of total daily calories
Trans Fat: the Ugly!
Who Loves Trans Fat?
• Bakeries, restaurants and food
manufacturers use it.
• Can withstand repeated heating and
cooking (especially deep-fried foods such
as french fries, donuts, others), has a long
shelf life in food (many types of baked or
pre-packaged snacks) and lasts a long
time before spoiling.
Where else can I find it?
• Beware of processed foods, fast foods and
frozen foods
• Trans fats are also known as trans-fatty
acids or may also be labeled as "partially
hydrogenated vegetable oil" or vegetable
shortening.
Why is trans fat so bad?
This type of fat is "man-made" by adding
hydrogen to vegetable oil through a
process known as "hydrogenation.“
The extra hydrogen atoms clog your heart
and raise levels of cholesterol.
How much trans fat should I eat?
Your daily dietary intake of trans fat should
be as close to zero as possible.
Here’s something to blow your
(nutritional) mind:
Just like we need some fat, we
also need some cholesterol!
WAIT…ISN’T IT TRUE THAT…
Too much cholesterol and the wrong type of
cholesterol lead to dangers such as strokes and
heart attacks.
What is cholesterol and why do we need it?
Cholesterol is a soft, fat-like
substance that:
• Protects cell
membranes
• Helps nerve cells
send messages
• Building block for
vitamin D
• Lets gallbladder make
bile
• Base for estrogren or
testosterone
Do any of these sound familiar?
• Cholesterol is carried through the bloodstream by
attaching to certain proteins. The combination is called a
lipoprotein. There are four different types of lipoproteins
that carry cholesterol in the blood:
• High density lipoprotein (HDL) or "good cholesterol"
• Low density lipoprotein (LDL) or "bad cholesterol"
• Very low density lipoproteins (VLDL), which are very
bad forms of cholesterol.
• Chylomicrons, which carry very little cholesterol, but
a lot of another fat called triglycerides.
Another reason trans fat is evil…
• Trans fat increases levels of bad
cholesterol (LDL)
• It also destroys good cholesterol (HDL)
And now for something completely
different