Transcript Carbohydrates, Lipids and Energy Balance

GOOD CARBS
BAD CARBS
http://www.healthination.com/diettips/know-your-ingredients/sound-thesugaralarm/?r=1&utm_source=rec_widget&utm_
term=68
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Carbohydrates are the primary source of fuel for the
body. They are the preferred source of energy for cells in
the brain and nervous system as well as during intense
exercise.
The Recommended Daily Allowance (RDA) for
carbohydrate is 130 g/day.
This is considered the minimum amount to supply
adequate glucose to the brain.
Carbohydrates provide 4 kcal/ gram. The Dietary
Recommended Intake or DRI for carbohydrate is 45 to
65% of total energy intake depending on your activity
levels.
Athletes working at higher intensity levels need a greater
percentage of energy as carbohydrates in their diets.
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All carbohydrates are composed of chains of carbon,
hydrogen, and oxygen and are found in a wide
variety of foods.
The primary sources of carbohydrates are grains
such as wheat, corn and rice, as well as fruits and
vegetables. In other words, plant foods.
Other sources of carbohydrate include milk and
legumes (beans and peas).
Fiber is an important carbohydrate found in whole
grains and fruits and vegetables.
Fiber does not provide energy because it cannot be
absorbed by the body.
Simple carbohydrates (sugars).
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Simple sugars include monosaccharides (one
sugar) and disaccharides (two sugars joined
together).
Common monosaccharaides:
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Glucose is the main type of sugar in the blood and
is the major source of energy for the body's cells
Fructose or fruit sugar and is the sweetest of the
monosaccharides.
Galactose only occurs as a component of lactose or
milk sugar. It never exists alone in foods.
Module of a glucose molecule
Common disaccharides:
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Lactose found in milk from cows and human breast
milk.
Maltose produced by the body when breaking down
starchy foods.
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Sucrose or table sugar contains one glucose molecule and
one fructose molecule.
https://www.youtube.com/watch?v=6esFO
qj_IaY
Polysaccharides or Complex carbohydrates
refer to molecules of glucose bonded together to form
long chains usually made of glucose, galactose and
fructose.
Starches and Fiber
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We ingest starches from
◦ grains (wheat, corn, rice, and oats)
◦ legumes (beans and peas)
◦ tubers (potatoes and yams)
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Most starches are easily digested and
provide excellent sources of energy.
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Food scientists use the term resistant
starch for those starches linked by bonds
that are relatively indigestible as a result
they are classified as a fiber.
Fiber can be classified as soluble or insoluble.
Soluble fibers dissolve in water to form a
viscous gel.
 They are easily digested by bacteria in the
colon through fermentation.
 Sources of soluble fiber include oats, beans,
citrus fruits, and berries.
 Research has demonstrated that soluble fiber
binds cholesterol and glucose in the digestive
tract, limiting the amount that can be
absorbed.
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Insoluble fiber does not dissolve in water and
cannot be fermented by bacteria in the large
intestine.
Insoluble fiber promotes digestive health by
promoting more rapid transit of foods through the
digestive tract, preventing constipation and also
preventing diverticulitis.
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DRI for women 25g/day and 38g/day for men.
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https://www.youtube.com/watch?v=rEKE
S8Vp4ZU
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Sugar
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https://www.youtube.com/watch?v=lEXBxijQ
REo
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http://www.nytimes.com/2014/12/23/opinio
n/sugar-season-its-everywhere-andaddictive.html?_r=0
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http://www.healthination.com/nutritionessentials/nutrition-essentials/essentialssugar/
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Examples of insoluble fiber include:
◦ Lignins found in bran (the husks of whole grains such as
wheat), and in the woody parts of plant cell walls such as
carrots and the berry seeds. They are not digestible at all by
intestinal bacteria.
◦ Cellulose, the main component of cell walls which gives plants
their structure. When we eat whole grains, fruits, vegetables
and legumes we are getting cellulose. In addition, food
scientists found that it can be extracted from wood pulp or
cotton for use as thickeners, anti-caking agents, and
texturizing of foods.
◦ Hemicelluloses surround cellulose in the cell walls and are the
primary component of cereal fibers. Whole grains and
vegetables are good sources of hemicelluloses which are also
sometimes classified as soluble fibers.
Digestion and Absorption of Carbohydrates
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When we digest carbohydrates the ultimate end product is
glucose which we use for energy.
When we ingest carbohydrate-containing foods, we start with
polysaccharides that need to be broken down into
monosaccharides.
Monosaccharides are then converted to glucose and absorbed by
the small intestine.
Carbohydrate digestion begins in the mouth where salivary
amylase in saliva begins to break down starches into smaller
particles called disaccharides.
That sweet taste in your mouth when you chew on a piece of
toast is the disaccharide maltose.
The bolus of food that leaves your mouth is passed through the
esophagus into the stomach where the stomach acid causes
digestion of carbohydrates to cease temporarily.
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Carbohydrate digestion resumes in the small
intestine.
As the stomach contents empty by spurts into the
small intestine, pancreatic amylase is secreted by
the pancreas into the small intestine to break down
any remaining starch into maltose.
The mucosal cells of the microvilli lining the small
intestine secrete enzymes to break down
disaccharides into their respective monosaccharides:
◦ Maltase converts maltose into glucose.
◦ Sucrase breaks down sucrose into glucose and fructose.
◦ Lactase completes the digestion of lactose into glucose and
galactase.
The mucosal cells of the small intestines
absorb the monosaccharides so they can
enter the bloodstream and travel to the liver
to be processed.
 Glucose and galactose are absorbed via an
active transport mechanism involving a
carrier protein saturated with sodium.
 This process uses ATP to provide energy.
 Absorption of fructose occurs more slowly
through facilitated diffusion which requires
no energy.
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In the liver, fructose and galactose are
converted to glucose to be used for immediate
energy or to be converted to glycogen and
stored in the liver or muscles for later use.
When the liver has reached its capacity to store
glycogen, excess glucose is stored as fat in
adipose tissue.
When you exercise heavily or miss a meal or go
on a fast, the body breaks down glycogen into
glucose to prevent blood sugar levels from
dropping too low for the body to function.
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Regulation of blood
glucose requires a
number of hormones,
including insulin,
glucagon, epinephrine,
norepinephrine, cortisol,
and growth hormone.
In healthy individuals,
these hormones balance
each other to control
blood glucose in a fairly
tight range.
Regulation of Blood Glucose Levels
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Following a meal, our blood
glucose rises and insulin is
necessary to assist glucose across
the membranes of the cells in our
body.
Sometimes thought of as the key
that opens the gates of the cell
membranes, insulin is a hormone
secreted by the beta cells in the
pancreas.
Insulin functions to stimulate
special glucose transport proteins
in cells throughout the body to
allow glucose in.
Insulin is also involved in the
process of storing glucose as
glycogen in liver and muscle cells.
A decrease in blood glucose occurs when you
have not eaten for some time.
 When this happens the alpha cells of the
pancreas secrete glucagon to convert
glycogen back into glucose.
 During periods of fasting as glycogen stores
become depleted, glucagon assists in the
breakdown of body proteins into amino acids.
 Approximately half of the amino acids in the
body can be converted to glucose to be used
for energy.
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This is why diets that severely restrict calories
cause the loss of about 50% muscle and 50%
fat.
 Not what most of us really want.
 Gluconeogenesis is the term for the
production of glucose from amino acids.
Note: Fatty acids cannot be converted to
glucose.
 Carbohydrates are the main fuel of the body
and needed to spare protein for functions
other than energy.
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The other hormones involved in blood glucose regulation
are especially important in times of stress.
For example, epinephrine and norepinephrine are secreted
by the adrenal glands to increase breakdown of glycogen
in the liver as well as increase gluconeogenesis.
Cotisol increases gluconeogenesis and decreases use of
glucose by muscles and organs, and growth hormone
increases the liver’s output of glucose, decreases uptake
of glucose by the muscles, and increase mobilization of
fatty acids from adipose tissue.
Have you ever heard of “flight or fight”?
These hormones can get the body ready for emergency
situations.
The Glycemic Index:
 What’s all the hype about low glycemic foods?
 The glycemic index is the term for a
measure of how quickly a given amount (50g)
of a particular food (eaten alone) raises the
blood sugar in comparison to pure glucose.
 Foods with a high glycemic index cause blood
glucose to rise rapidly.
The Glycemic Index:
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This rapid rise in blood sugar can trigger a large
increase in insulin which may in turn cause the
blood sugar to drop.
The glycemic index was originally developed as
an attempt to help people with diabetes.
However, we eat most of our foods together with
other foods. In addition to the type of
carbohydrate, the way a food is prepared, as well
as fat and fiber content (which can slow
digestion) all affect how quickly our blood sugar
will rise.
The Glycemic Index:
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The glycemic load is considered a more useful tool by some
experts.
The glycemic load of a food is the total grams of carbohydrate in
that food multiplied by the glycemic index of that particular
carbohydrate.
Foods that have a high glycemic index may have a low glycemic
load if the total carbohydrate content is low.
Generally speaking, foods higher in fiber tend to have a lower
glycemic index which helps prevent dramatic fluctuations in
blood glucose.
The use of low glycemic foods is controversial at this point.
This is due in part to the complexity of the concept which makes
it burdensome for the average person to use.
For now, the best advice is to choose foods with little processing
The Glycemic Index:
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For more information on the carbohydrate
content of foods:
http://www.nal.usda.gov/fnic/foodcomp/Data/SR
20/nutrlist/sr20a205.pdf
http://www.nlm.nih.gov/medlineplus/tutorials/di
abetesintroduction/htm/_no_50_no_0.htm
http://www.sciencenetlinks.com/tools.php?DocID
=178&Grade=9-12
http://www.ncbi.nlm.nih.gov/pubmed/20301013
http://www.health.gov/dietaryguidelines/dga200
5/healthieryou/html/chapter8.html
Lipids:
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You may know lipids as fats and oils.
Lipids is the name given to a large and
diverse group of substances that are
not soluble in water.
You have heard the expression “Oil and
water don’t mix.” It’s true they don’t.
They are hydrophobic - they repel each
other and oil floats on water.
When you shake a bottle of Italian
dressing, the oil is dispersed into the
vinegar, but it separates back out very
quickly.
Vinegar is primarily water.
What do you think?
Fat is bad for your health so we
should consume as little as
possible. True or False?
 High fat diets cause cancer. True or
False?
 Some fats protect against heart
disease. True or False?
 Fried foods are okay for you as
long as they are fried in vegetable
shortening. True or False?
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Types of Lipids
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The most common form of lipids is triglycerides. In lay terms
triglycerides are referred to as fats.
About 95% of the fat in our foods is in the form of triglycerides.
We also store triglycerides as adipose tissue or body fat.
The tri- in triglycerides refers to the 3 fatty acids connected to a
glycerol “backbone”.
Fatty acids are long chains of carbon atoms bonded to other
carbon atoms and hydrogen.
The carboxyl group (-COOH) at the end is what makes them an
acid. Just as in carbohydrates, fats contain carbon, hydrogen,
and oxygen but they are arranged differently.
The glycerol backbone is an alcohol that contains 3 carbon
atoms each attached to a fatty acid.
http://www.chem4kids.com/files/bio_lipids.html
Types of Lipids
 The three fatty acids can all be different, all
the same, or only two the same.
 In addition, they can be saturated or
unsaturated fatty acids.
 Chain lengths of the fatty acids in naturally
occurring triglycerides can be of varying
lengths but 16, 18 and 20 carbons are the
most common.
 Natural fatty acids found in plants and
animals are typically composed only of even
numbers of carbon atoms.
Types of Lipids
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Triglycerides can be classified according to chain
length (number of carbons), level of saturation
(number of hydrogen atoms), and by their shape.
Fatty acid chain length is important because it
determines how easily they are digested and
metabolized.
Long –chain fatty acids containing fourteen or
more carbons in length are more abundant in nature
and our food supply.
Medium chain fatty acids have six to twelve
carbons, and short-chain fatty acids generally
contain fewer than six carbon atoms.
Triglycerides are also classified by their degree of
saturation.
 A saturated fatty acid (SFA) is saturated with the
maximum amount of hydrogen atoms.
 They are generally solid at room temperature because of
their straight chains which stack together.
 Foods with the highest saturated fat content in include,
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butter
cream
lard
beef fat
whole milk
coconut oil
B palm oil
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Our bodies make cholesterol from the saturated fat in
our diets.
Saturated fats, trans fats, and cholesterol tend to
raise “bad” (LDL) cholesterol levels in the blood,
which in turn increases the risk for heart disease.
To lower risk for heart disease, we should cut back on
foods containing saturated fats, trans fats and
cholesterol.
http://abcnews.go.com/Health/video/cholesterolmanagement-cardiovascular-disease-risk-heart12877544?tab=9482931&section=1206835&playlist=
3547557&page=3
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Monounsaturated fatty acids (MUFAS) have
hydrogen atoms missing at only one double bond
(Mono- means one) and are liquid at room
temperature. Olive oil, canola oil, peanut oil, cashew
nuts and avocado are high in monounsaturated fatty
acids.
Polyunsaturated fatty acids (PUFAS) are those
containing more than one double bond (poly means
many) and are also liquid at room temperature.
Corn, cottonseed, and soybean oils are examples of
polyunsaturated fatty acids. The “kinks” created by
the double bonds prevents them from packing tightly
together, making them liquid nature.
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Actually, all foods contain a combination of the various types of
fatty acids which affects their use in cooking as well as their
contribution to health. The following chart shows the percentages of
each type of fat found in various fats and oils used in food
preparation.
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Hydrogenation is the process by which hydrogen
atoms are added to fatty acids in otherwise healthy
oils, straightening out the double bonds to make
them more solid at room temperature.
This process was developed several decades ago to
increase the shelf life of foods such as cakes,
cookies, pastries, and other foods made with
“shortening” and to make crackers crisper.
The extra hydrogen atoms decrease the tendency of
these foods to undergo oxidation making them less
likely to become rancid.
However, when the hydrogen atoms are added back,
they connect across the double bonds and are called
trans fats.
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Most naturally occurring fatty acids with double
bonds have the hydrogen atoms on the same side of
the double bond and this is referred to as cis.
Research now indicates that diets high in trans fats
are associated with increased risk of cardiovascular
disease just like diets high in naturally occurring
saturated fats.
As of Jan. 1, 2006, The U.S. Food and Drug
Administration (FDA) requires that trans fats be listed
on food labels in addition to saturated fats.
Amounts less than 0.5 g are reported as none, so be
sure to look for the word hydrogenated on labels.
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Frito Lay was one of the first companies to
announce a change in product to meet FDA
requirements.
They are a direct store delivery (DSD) product
which means a route manager visits stores
almost daily to rotate product on the shelf and
remove outdated product.
This decreases the likelihood of product
becoming rancid.
◦ Read more… http://www.fritolay.com/about-us/pressrelease-20020924.html
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Altering the fat content and/or type of fat in
foods to make them healthier and yet maintain
flavor is a major job of food scientists these
days.
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Did you know that some fats are essential? Essential fatty acids are
those that must be consumed in foods because our bodies cannot make
them.
Two fatty acids, linoleic acid and alpha-linoleic acid are considered essential
because we cannot make them.
As long as we have adequate amounts of these two fatty acids we can
make all the others as we need them.
Most Americans get adequate amounts of Linoleic acid (omega-6-fatty
acid) because we get plenty of vegetable and nut oils such as corn, soy,
peanut, sunflower and safflower oils or use vegetable oil margarines.
Linoleic acid is converted in the body to arachidonic acid which is a
prescursor to several ecosanoids. Ecosanoids are important biological
compounds and include prostaglandins, thromboxanes, and leukotrienes.
Their functions include regulation of gastrointestinal motility, secretory
activity, blood clotting, vasodilation and vasoconstriction, vascular
permeability, and inflammation.
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Alpha-linoleic acid (omega-3-fatty acid) is found in
dark, green leafy vegetables, flaxseeds and flaxseed
oil, walnuts and walnut oil, canola oil, and soybeans
and soybean oil.
Fish, shellfish, and fish oils contain two omega-3
fatty acids, eicosapentanoic acid (EPA) and
docohexanoic acid (DHA).
That’s a mouthful! Can you pronounce them?
Oily fish such as salmon and tuna contain more of
these two oils and that is why you will hear the
recommendations to eat more of these fish.
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Scientific evidence indicates that diets high in EPA
and DHA reduce the risk of heart disease.
EPA and DHA stimulate the production of
prostaglandins and thromboxanes, reduce
inflammatory responses in the body, and reduce
blood clotting and plasma triglycerides.
Many Americans get omega-6 fatty acids in a much
higher proportion than omega-3 fatty acids, which
increases blood clotting and vasoconstriction of the
blood vessels leading to increased risk of heart
attacks.
Generally speaking, omega-6 and omega-3 fatty
acids have opposite effects so they should be kept in
balance when choosing foods.
Recommendations for Fat Intake
 Lipids in the form of fats are a major source of energy
during physical activity. Fats provide more than twice as
much energy as carbohydrates.
 One gram of fat provides 9 kcals while one gram of
carbohydrates provides 4 kcals.
 Did you know that one tablespoon of butter or margarine
provides 100 calories?
 That amounts to 10 lbs per year if you don’t burn it off!
 Fat is easily stored as adipose tissue when we overeat.
 The best way to prevent weight gain is to engage
regularly in lower intensity physical activity such as
walking.
Recommendations for Fat Intake
 We need some fat in our diet to maintain optimum health.
 Fats in foods help us feel satiated because they help slow
digestion and make us feel full longer.
 Fats also contribute to the flavor and texture of foods.
 The essential fatty acids we get from foods are needed to
make our cell membranes and to help maintain cell
function and protect the cell membrane.
 In addition, we need fat to enable the absorption and
transport of the fat soluble vitamins.
 Because fats make foods smooth and creamy and bring
out the flavors of some foods such as mushrooms in
butter it is easy to eat more fatty foods than we need.
The AMDR for total fat is 20% to 35% of total energy.
◦ http://www.iom.edu/Global/News%20Announcements/~
/media/C5CD2DD7840544979A549EC47E56A02B.ashx
 Many Americans eat within these limits but eat too much
of the unhealthy fats.
 To reduce the risk of cardiovascular disease, the American
Heart Association recommends saturated fats be reduced
to less than 7% of total energy
http://www.heart.org/HEARTORG/GettingHealthy/Nutrition
Center/HealthyDietGoals/Healthy-DietGoals_UCM_310436_SubHomePage.jsp , and trans fatty
acids should be reduced to an absolute minimum.
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http://www.health.gov/dietaryguidelines/dga2005/he
althieryou/html/chapter8.html
Choosing more sources of monounsaturated and
polyunsaturated fats in place of saturated fats is the
best strategy for heart health.
The AI for linolenic acid (omega-6-fatty acid) is 14 to
17g/day for adult men and 11 to 12g/day for adult
women.
The AI for alpha- linoleic acid (omega-3-fatty acid) is
1.6g/day for adult men and 1.1g/day for adult
women.
More Lipids
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Phospholipids are a type of lipid in which a glycerol molecule combines
with two fatty acids on the first and second carbon and a phosphate
molecule on the third.
Unlike other lipids, the phosphate makes phospholipids soluble in water.
Phospholipids help with the digestion of dietary fats and carry other lipids
through the bloodstream.
In addition, phospholipids are an important part of the structure of cell
membranes, as well as regulating transport of substances in and out of the
cell.
Have you ever known anyone who took lecithin supplements?
In the liver, phospholipids called lecithins combine with bile salts and
electrolytes to make bile which emulsifies lipids as part of the digestive
process.
Since we are able to make lecithin it is not essential to get it from foods (or
supplements).
In addition, it is found in abundant amounts in egg yolks, peanuts, and
soybeans, as well as processed foods containing emulsifiers (additives that
help foods stay blended.
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Sterols are a type of lipid that contain multiple-ring
structures.
The most well-known sterol is cholesterol which is
found only in animal foods.
While most of the cholesterol in foods is associated
with the fatty portion of animal foods such as butter,
egg yolks, whole milk and fatty meats, even lean
meats and low-fat dairy products have some
cholesterol.
We don’t need to get cholesterol from food because
we make it.
The cholesterol we make contributes to our health in
many ways.
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Cholesterol is part of every cell membrane and a
necessary component of the sex hormones
(estrogen, progesterone, and testosterone), adrenal
hormones, and vitamin D.
For the majority of humans, the saturated fat content
of the diet has a greater bearing on blood levels of
cholesterol than ingesting cholesterol itself.
Foods high in saturated fat include bacon, sausage,
biscuits, and gravy eaten with (or instead of) eggs.
The human body makes cholesterol from saturated
fats in the liver, adrenal cortex, intestines, and
reproductive tissues.
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To clear up some of the misconceptions about
cholesterol and saturated fat view the following
video:
◦ http://www.eggnutritioncenter.org/page/maria-luz-fernandez-ph-d
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For information on the cholesterol content of eggs:
◦ http://www.eggnutritioncenter.org/page/ken-anderson-ph-d
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Plants also contain some sterols but we do not
absorb them easily.
Plant stanols and sterols have a structure similar to
cholesterol.
In fact, plant sterols when eaten appear to block the
absorption of cholesterol in the gut, possibly by
competing for absorption sites.
Food scientists developed the product Benecol® to aid in
lowering blood levels of cholesterol.
 Benecol® is one of many products in a category called
functional foods.
 The following was obtained from the Benecol® Website
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◦ http://www.benecol.net/bp.asp?viewID=2844
Plant stanols and sterols have also been added to foods
and beverages such as orange juice.
 When consumed on a daily basis, these products can
lower blood cholesterol levels below the amount that can
be achieved by avoiding saturated fats alone.
 For more information on these products
http://smartbalance.com/nutrition/whydifferent and
http://www.nutraingredients.com/Research/Plant-sterolsin-juice-improve-cholesterol-levels
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What are functional ingredients and foods? (from
http://www.benecol.net/functional_ingredients )
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Functional ingredients are ingredients that have health
improving or disease risk reduction properties and are added to
functional food products for easy and convenient consumption.
Functional foods are consumed as part of a regular diet but are
demonstrated to have benefits beyond basic nutritional
functions.
Some functional ingredients are derived from natural sources.
The health claims of functional food products are regulated by
governmental bodies such as the FDA in the United States.
Functional foods form a 20 to 30 billion dollar market that is
growing faster than conventional foods and offers higher and
more stable profit margins.
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What is plant stanol ester?
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Plant Stanol Ester is the active functional ingredient in
Benecol products.
Plant stanol ester is a functional ingredient that has been
proven to reduce bad (LDL) cholesterol.
The daily use of 2 g of plant stanol can reduce LDLcholesterol up to 15% after two weeks1.
The cholesterol lowering effect is supported by more than
60 clinical trials.
With plant stanol ester you can easily tap into the health
conscious consumer market and command a higher
premium for your product.
Plant stanol ester has obtained a Generally Recognized as
Safe (GRAS) status in the United States in 1999.
One of the ten greatest discoveries in nutrition worldwide
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The Finnish innovation-based, cholesterol-lowering functional ingredient
plant stanol ester was recently selected as one of the ten greatest
discoveries in nutrition worldwide.
The review2 published in European Journal of Clinical Nutrition in January
2009 presented the greatest discoveries related to nutrition during the past
30 years.
The discoveries chosen were based on the views of the world's leading
nutrition researchers and solid research data.
1. e.g. Gylling et al. 1997, Miettinen et al. 1995. See full reference list
2. Katan et al. Which are the greatest recent discoveries and the greatest
challenges in Nutrition? Eur J Clin Nutr 2009; 63: 2-10.
(Available on the internet at: www.nature.com/ejcn/index.html)
If you want to know more about functional foods, you can subscribe to a
free newsletter that provides an update on research on functional foods.
◦ http://www.nutraingredients.com/Research/Plant-sterols-in-juice-improvecholesterol-levels
Digestion of lipids
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Dietary fats are usually found as part of other foods and
digestion of fats occurs primarily in the small intestine.
Lipid digestion begins in the stomach with gastric lipase
breaking lipids into smaller particles.
As the lipid droplets pass into the small intestine, the
gallbladder contracts to release bile to emulsify the oil droplets.
Emulsifiers, including lecithin act like soap to break the lipid
droplets into even smaller droplets.
This increases the surface area of the droplets to make it easier
for lipid-digesting enzymes to work.
Two hormones, cholecystokinin and secretin cause the
gallbladder to contract and simultaneously cause the release of
bicarbonate to neutralize stomach acid and pancreatic digestive
enzymes into the small intestine.
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Each triglyceride molecule is broken down into a monacylglyceride
consisting of the glycerol backbone and one fatty acid attached to
the glycerol backbone, and two free fatty acids.
Co-Lipase anchors pancreatic lipase (the primary enzyme for
digesting lipids) to the lipid droplet so the fatty acids can be
removed by pancreatic lipase.
Other enzymes are needed to digest phospholipids and cholesterol
which exists as cholesterol esters.
The pancreas releases cholesterol esterase to break down
cholesterol into a free cholesterol molecule and a free fatty acid.
Phospholipids are broken into smaller parts by phospholipase.
The resulting smaller molecules are then ready to combine with
transporters to be absorbed through the intestinal wall into the
bloodstream.
Absorption of Lipids
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Most lipid absorption occurs in the mucosal lining of
the small intestine.
Micelles which are made of bile salts and biliary
phospholipids bind with free cholesterol, free fatty
acids and monoglycerides to transport to the
enterocytes for absorption.
Micelles are spherical compounds with a hydrophobic
core where the lipid products attach, and a
hydrophilic surface to allow transport in the watery
environment of the gut.
Absorption of Lipids
Once inside the enterocytes, fatty acids and
monoglyerides are reformed into triglycerides and
packaged into lipoproteins called chylomicrons.
 The chylomicrons are then released into the
lymphatic system which empties into the
bloodstream.
 Once in the bloodstream they can be used for energy
by cells, especially muscle cells, used to make lipidcontaining compounds in the body, or stored in the
muscle or adipose tissue for later use.

Energy Balance, Obesity and Disease Prevention
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Are you happy with your current weight?
Many Americans are not.
We are constantly bombarded with ads for weight loss diets that
promise amazing results.
How many diets have you tried?
Did you know you can lose weight on any diet by restricting
foods?
The problem with any so called weight loss diet is, how long can
you stick with that diet?
Most diets are too restrictive to maintain for the long term.
Check out the Fad diet timeline dating back to 1820 at
http://old.eatright.org/videos/nnm/timeline.swf

http://www.nutrition.gov/nal_displ
ay/index.php?info_center=11&tax_
level=2&tax_subject=390&topic_id
=1742&placement_default=0

The key to weight management is
to make gradual changes in overall
eating habits and physical activity
levels that you can stick with. The
two overarching concepts of the
2010 Dietary Guidelines for
Americans are: maintain calorie
balance over time to achieve
and sustain a healthy weight;
and focus on consuming
nutrient-dense foods and
beverages.

On page 8 of the 2010 Dietary Guidelines, it states,

“Maintain calorie balance over time to achieve and sustain a healthy
weight. People who are most successful at achieving and maintaining a
healthy weight do so through continued attention to consuming only
enough calories from foods and beverages to meet their needs and by
being physically active. To curb the obesity epidemic and improve their
health, many Americans must decrease the calories they consume and
increase the calories they expend through physical activity.

Focus on consuming nutrient-dense foods and beverages. Americans
currently consume too much sodium and too many calories from solid fats,
added sugars, and refined grains.2 These replace nutrient-dense foods and
beverages and make it difficult for people to achieve recommended nutrient
intake while controlling calorie and sodium intake. A healthy eating pattern
limits intake of sodium, solid fats, added sugars, and refined grains and
emphasizes nutrient-dense foods and beverages—vegetables, fruits, whole
grains, fat-free or low-fat milk and milk products,3 seafood, lean meats and
poultry, eggs, beans and peas, and nuts, and seeds.”
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Do you need help with food choices?
See shopping tips from a registered dietitian
http://abcnews.go.com/Health/video/grocery-checklist-food-shoppinghealthy-health-diet-eating-healthing12983174?tab=9482931&section=1206835&playlist=3547557&page=1
With the introduction of the 2010 Dietary Guidelines for Americans,
someone coined the phrase “Get off your SoFAAS.” SoFAAS is an acronym
for solid fats, alcoholic beverages and added sugars.
The following link provides a chart showing the mean (standard error) and
percentiles of usual intake of Americans from 2001-2004 from solid fats,
alcoholic beverages and added sugars (SoFAAS)
http://riskfactor.cancer.gov/diet/usualintak
es/sofaas.html
 What’s the big deal?
 For one thing, Solid fats contain more
saturated fats and/or trans fats than
oils.
 Trans fats can be found in many cakes,
cookies, crackers, icings, margarines,
and even microwave popcorns.
 When you see “partially-hydrogenated
vegetable oil” on a food label it usually
contains trans fats.
 These fats increase your risk of
cardiovascular disease.
 Added sugars are those added to
processed foods as sugars or syrups and
add to the calorie content of those foods.
http://www.ars.usda.gov/Services/docs.
htm?docid=12107
Solid fats, alcoholic beverages and added sugars are
found in a significant number of foods that are not
nutrient dense.
 They are a source of “discretionary calories” first
described in the 2005 Dietary Guidelines.
 We all need a certain number of calories to keep our
bodies functioning and provide energy for physical
activities.
 Discretionary calories are those “extra” calories we
can choose beyond what we need to support our
basic needs.
 Athletes and other active people can use way more
discretionary calories than sedentary people.
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Your discretionary calorie allowance can be used to
eat more nutritious foods from any food group than
the food guide pyramid recommends.
For the most part, we use discretionary calories to
eat higher calorie forms of foods, containing solid
fats (whole milk) or added sugars(sweetened
yogurt), or eat foods that are purely for enjoyment
such as cakes and candy bars. Yum!
Discretionary calories are sometimes called “empty
calories,” especially when referring to sweets because
all of the calories in candy, sodas, alcoholic
beverages, and solid fats are discretionary calories.
These foods provide almost no nutrients other than
carbohydrates and fats.

View the following for a full explanation of discretionary calories
http://www.mypyramid.gov/pyramid/discretionary_calories.html

For a description and examples of solid fats see
http://www.mypyramid.gov/pyramid/discretionary_calories_fats.html

For a table of solid fats see
http://www.mypyramid.gov/pyramid/discretionary_calories_fats_count
_table.html

For a description and examples of added sugars
http://www.mypyramid.gov/pyramid/discretionary_calories_sugars.htm
l

For a comparison of discretionary calories by food groups
http://www.mypyramid.gov/pyramid/discretionary_calories_count_tabl
e.html
An example of how to count discretionary calories from the milk group is
as follows:
Milk Group Item
Serving Estimated
size
Total Calorie
s
Estimated
Discretionary
Calories
Fat-free milk
1% milk
2% milk (reduced
fat)
Whole milk
1 cup
1 cup
1 cup
1 cup
85
100
125
145
0
20
40
65
http://www.mypyramid.gov/pyramid/discretionary_calories_count_table.html
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Fats are concentrated sources of calories (9 kcals/ g).
If you choose one cup of whole milk every day, you will get an
additional 2 teaspoons of fat (8 grams) resulting in
approximately 65 “extra” or discretionary kilocalories.
If you drink two glasses of milk per day in attempt to meet the
Dietary Guidelines recommendation of 3 servings from the milk
group you will have 130 extra calories a day resulting in about
13 pounds per year.
One pound of fat contains 3500 kilocalories.
You do the math…
130 kcal x 365 days = 47,450 kcal
47,450 kcal/ 3500kcal/lb = 13.6 pounds per year
As a rule of thumb, 100 extra calories a day is 100
pounds a year.
 This means that if a can of soda has 150 kcal, one
can per day every day for a year results in a weight
gain of 15 pounds per year.
 How many cans of regular soda do you drink per
day?
 If you drink soda in 20 oz bottles you get even more
calories. Yikes!
 A 250- kcal candy bar, eaten every day results in 25
pounds per year, unless those calories are expended
through physical activity.
 As you can see, it is not hard to become overweight
with time.

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How can you “burn” enough calories to eat even one
candy bar on a given day? The following link provides
a chart to show the amount of calories burned by the
reference 154 pound person in 30 minutes or one
hour.
◦ http://www.fns.usda.gov/eatsmartplayhardhealthylifestyle/To
ols/calorieburnerchart.htm

According to the chart, it would take 30 minutes of
aerobic dance or walking at a pace of 4 ½ mph, or
one hour of walking at a pace of 3 ½ mph to expend
enough energy to eat one average candy bar. Is that
candy bar worth it?
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One of the other issues we face is that our portion sizes have
increased over the last several decades.
For example, in the 1960’s adults ate the equivalent of a Happy
Meal when they went to McDonald’s!
Now everything is supersized.
Check out the following http://hp2010.nhlbihin.net/portion/
The National Heart, Lung, and Blood Institute (NHLBI) has
downloadable slide shows that compare today’s portion sizes
with those of 20 years ago.
◦ http://hp2010.nhlbihin.net/oei_ss/menu.htm#PD2
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Yikes! No wonder so many people are overweight.
Incidentally, the 150 lb reference person also goes back to at
least the 1970s.
Did you know that many people don’t realize that they are
overweight?
That is because the majority of Americans are overweight so we
How about you? Is your current weight
a healthy weight? Although nutrition
experts still debate the precise limits of
what constitutes a healthy weight, you
can determine your own weight to be
healthy if it is:
◦ Appropriate for your age and physical
development
◦ Can be achieved and maintained without
severely restricting food intake or
constant dieting
◦ Based on genetic background and family
history of body shape and weight
◦ Allows you to maintain normal blood
pressure, blood lipid levels, and glucose
tolerance
◦ Promotes good eating habits and allows
you to participate in regular physical
activity
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One way to evaluate your body weight is to use the
body mass index calculator.
Developed as a screening tool for sedentary adult
men and women, body mass index (BMI) is a
measure of body fat based on height and weight.
The standard BMI formula based on the metric
system:
◦ BMI (kg/m2) = weight (kg)/height (m2)

Try the following BMI calculator at
◦ http://www.nhlbisupport.com/bmi/

You can also download a BMI calculator app for your
phone.
BMI Categories are as follows:
◦ Underweight = <18.5 (having too little body fat to
maintain health; increased risk for infections)
◦ Normal weight = 18.5–24.9
◦ Overweight = 25–29.9 (Having a moderate amount
of excess fat over an accepted standard but not
obese)
◦ Obesity = BMI of 30 or greater (having excess body
fat that adversely affects health; increased risk of
chronic disease)
◦ Morbid Obesity = BMI of 40 or greater (body
weight exceeds 100% of normal; very high risk for
serious health consequences)

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Most people know that being
overweight isn’t healthy, but being
too thin isn’t healthy either.
Having a BMI value below 18.5 kg/m2
or above 30kg/m2 is associated with
an increased risk of premature
mortality.
Ideal weight is having a BMI
betwen18.5 and 24.9. It should be
noted that BMI is not a good tool for
athletes.
Muscle is heavy because it is about
75% water so an individual with a lot
of muscle is going to weigh more at a
given height than a sedentary
person.
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If you need to lose weight,
remember that a pound of fat
equals 3500 calories.
To lose 1 pound a week you
will need to use 3500 more
calories than you eat that
week.
That amounts to 500 kcal/day.
Losing 1-2 pounds of fat a
week is a sensible goal and
using a combination of
increased activity and eating
less that will total 3500
calories for 7 days is generally
the most tolerable way to go.
BMI Graph
Source:
http://www.chartsgraphsdiagrams.com/HealthCharts/bmistatus.html
BMI in Table Format
What is obesity?
Listen to the following podcast.
http://www2c.cdc.gov/podcasts/player.asp?f=11505
 Latest Findings
http://www.cdc.gov/vitalsigns/AdultObesity/LatestFindings.html
Adult Obesity
Obesity is a national epidemic, causing higher medical costs and a lower
quality of life.

◦ Obesity means having excess body fat.
◦ Obesity is defined by body mass index, or BMI, which is calculated
from your height and weight.
◦ BMI greater than or equal to 30 means you are obese.
◦ Non-Hispanic black women and Hispanics have the highest rates of
obesity (41.9% and 30.7%).
◦ Obesity is a contributing cause of many other health problems,
including heart disease, stroke, diabetes, and some types of cancer.
 These are some of the leading causes of death in the U.S. Obesity can cause sleep
apnea and breathing problems and make activity more difficult.
 Obesity can also cause problems during pregnancy or make it more difficult for a
woman to become pregnant.
◦ Obese persons require more costly medical care. This places a huge
financial burden on our medical care system.
Why is this epidemic happening?
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Weight gain occurs when people eat too much food and get too little physical
activity.
Societal and community changes have accompanied the rise in obesity.
People eat differently:
Some Americans have less access to stores and markets that provide healthy,
affordable food such as fruits and vegetables, especially in rural, minority and
lower-income neighborhoods. Restaurants, snack shops, and vending machines
provide food that is often higher in calories and fat than food made at home.
There is too much sugar in our diet. Six out of 10 adults drink at least 1 sugary
drink per day.
It is often easier and cheaper to get less healthy foods and beverages.
Foods high in sugar, fat, and salt are highly advertised and marketed.
Many communities are built in ways that make it difficult or unsafe to be
physically active:
Access to parks and recreation centers may be difficult or lacking and public
transportation may not available.
Safe routes for walking or biking to school, work, or play may not exist.

What can you do to find a balance? Check out this
video.
◦ http://www.cdc.gov/CDCtv/FindingBalance/Healthy Weight it's not a diet, it's a lifestyle!

It’s not just about the foods we eat but how we
balance our intake with the output of energy from
physical activity. For more information
◦ http://www.cdc.gov/healthyweight/index.html
◦ http://www.nutrition.gov/nal_display/index.php?info_center=
11&tax_level=1&tax_subject=390
Energy Balance Occurs When Energy Intake = Energy Expenditure
http://www.cdc.gov/healthyweight/calories/index.html
http://www.nhlbi.nih.gov/health/public/heart/obesity/wecan/healthyweight-basics/balance.htm
 Energy intake comes from the foods we eat. The energy content of
each food is a measure of the amount of carbohydrate, fat, protein,
(and alcohol) each food contains.
 For example, a box of cereal that promises 35% of your daily fiber (9g
total fiber) and 16g of whole grain has 110 kcals in a ¾ cup serving. It
contains 1.5 g of fat, 26g or carbohydrate (with 5 g soluble fiber and
4g insoluble fiber) and 3g protein.
1.5g fat x 9 kcal/g = 10.5 kcal from fat
26 g carbohydrate (– 4 g insoluble fiber) = 22 g x 4 kcal/g = 88 kcal
from carbohydrate
3 g protein x 4 kcal/g = 12 kcal from protein
 This cereal is low in fat (<3g/serving), high in fiber (9g/serving) and
made from whole oat flour as the first ingredient. ½ cup of skim milk
adds an additional 40 kcal with an additional 4 g of protein (16 kcal)
and 6g carbohydrate (24 kcal). It’s a pretty good choice.
Energy expenditure (energy output) is
more than just physical activity.
 It includes the energy used by the body to
maintain its basic functions such as
respiration, circulation, and digestion, as well
as physical activity. The three components of
energy expenditure include:

◦ basal metabolic rate (BMR) 60% to 75% of our
total energy output
◦ thermic effect of food (TEF) 5% to 10%
◦ energy cost of physical activity 15% to 35%

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Basal Metabolic Rate, commonly referred to as
BMR is the energy used to maintain the body’s basal
or resting functions.
We use energy to breath, circulate blood, make new
cells and tissues, secrete hormones, and for nerve
conduction.
In other words, just to stay alive! BMR is measured
at rest.
Our individual BMR is determined primarily by the
amount of lean body mass we have. People with
more lean body mass (mainly as muscle) have a
higher BMR.
That means they burn more calories even at rest
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Unfortunately, BMR decreases with age, mostly due
to lack of physical activity.
We lose muscle as we become more sedentary with
age.
Unfortunately, our BMR decreases about 3% to 5%
for each decade after the age of 30.
Of course, this decline in muscle mass can be
prevented to some degree with regular physical
activity.
For more information on the benefits of physical
activity, see the Physical Activity Guidelines for
Americans, first published in October of 2008.
http://www.cdc.gov/physicalactivity/everyone/guideli
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The thermic effect of food (TER) is the amount of
energy needed to process the foods we eat.
It is the energy necessary to digest, absorb,
transport, metabolize, and store the nutrients we get
from our foods.
The amount of energy used depends on the source
of calories.
Incidentally, fat takes very little energy to digest,
while protein and carbohydrate take more energy to
process.
Have you ever felt a bit warm after eating a large
meal? This is due to the thermic effect of food.
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The energy cost of physical activity represents about 15%
to 35% of our total energy output and is highly variable.
It is the energy used to move about whether as work or
exercise.
It is the energy used to clean house, do yard work, or play.
The more active a person is (including fidgeting), the more
energy expended.
In the 1930’s the average person spent 2400 kcal day through
daily work.
By the 1990’s it was about 600 due to all the modern
conveniences.
Finding ways to take more steps by taking stairs instead of an
elevator or parking your car farther out in a parking lot are
ways to use more energy that add up over time.
Our bodies were meant to move!
The National Weight Control Registry is a
United States register of people at least 18
years or older who have lost at least 30 lb of
weight and kept it off for at least one year.
 Members lost weight by a wide variety of
methods, but most included reducing food
intake and increasing exercise.
 During the maintenance phase, almost all of
the registry members ate breakfast and
weighed themselves regularly, usually once a
week.

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Check out their research findings at
◦ http://www.nwcr.ws/Research/published%20research.htm
◦ http://www.nlm.nih.gov/medlineplus/tutorials/weightmanagement/htm/_yes
_50_no_0.htm
◦ http://classroom.kidshealth.org/classroom/9to12/personal/nutrition/energy_
balance.pdf
◦ http://classroom.kidshealth.org/9to12/personal/nutrition/energy_balance_qui
z.pdf
◦ http://healthlit.org/scienceInside/documents/Obesitybook.pdf
◦ http://kidshealth.org/teen/food_fitness/#cat20595
◦ http://science.education.nih.gov/supplements/nih4/energy/guide/lesson3.ht
m
◦ http://science.education.nih.gov/supplements/nih4/energy/guide/info-