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It is safe to say that one thing you'll do today is eat some
food -- food is pretty important to all animals. If you don't
eat, it can cause all sorts of problems: hunger,
weakness, starvation... Food is essential to life. But
what is food? What's in food that makes it so important?
What happens to the food once you eat it? What is food
made of? How does it fuel our bodies? What do words
like "carbohydrates" and "fats" really mean (especially
on those "Nutrition Facts" labels you find on almost
everything these days)? What would happen if you ate
nothing but marshmallows for a week? What is a
calorie? Why can't we eat grass like a cow or wood like
a termite?
© BNF 2005
Old Food Guide Pyramid - 1992
© BNF 2005
http://www.mypyramid.gov/global_nav/media_animation-presentation_eng_pc.html
© BNF 2005
“Discretionary calories” is
a term used in MyPyramid
recommendations …
Calories In must equal Calories Out
© BNF 2005
Kilogram calorie
The kilogram calorie, large calorie, food calorie,
Calorie (capital C) or just calorie (lowercase c) is the
amount of energy required to raise the temperature of
one kilogram (Liter) of water by one degree Celsius.
The convention of using the capital C for the kilogram
calorie and the lower case c for the gram calorie is
advocated by some but not generally followed.
Gram calorie
The gram calorie, small calorie or calorie (cal) is the
amount of energy required to raise the temperature of
one gram (mL) of water by 1 °C. The gram calorie
was once commonly used in chemistry and physics.
© BNF 2005
Think of your calories like a budget
“Essentials”
“Extras” or
“discretionary calories”
(IF you have any left to spend!)
“Essential” vs. “discretionary” calories
“Essential calories” are the
minimum calories required
to meet your nutrient
needs.
The best nutrient “buys”
are those foods with:
• the least amount of fat
• no added sugar
Definition: Discretionary
calorie allowance
“Discretionary”
“Essential”
Balance of calories remaining
in a person’s energy
allowance after accounting for
the number of calories
needed to meet
recommended nutrient intakes
through consumption of foods
in low-fat or no added sugar
forms.
http://mypyramid.gov/downloads/MyPyramid_education_framework.pdf
© BNF 2005
You can spend your
“discretionary calories” on:
• Foods with added sugar
• Foods higher in fat
• Increased intake of foods
within the food groups
© BNF 2005
Foods containing most of the
added sugars in American diets
are:
•
•
•
•
•
•
Regular soft drinks
Candy
Cakes
Cookies
Pies
Fruit drinks, such as
fruitades and fruit punch
• Milk-based desserts and
products, such as ice cream,
sweetened yogurt and sweetened milk
• Grain products, such as sweet rolls and
cinnamon toast
http://mypyramid.gov/pyramid/discretionary_calories_sugars.html
Definition: Solid fats
Solid fats are fats solid at room temperature, like butter
and shortening. Solid fats come from many animal foods
and can be made from vegetable oils through a process
called hydrogenation. Some common solid fats are:
• Butter
• Beef fat (tallow, suet)
• Chicken fat
• Pork fat (lard)
• Stick margarine
• Shortening
© BNF 2005
http://mypyramid.gov/pyramid/discretionary_calories_fats.html
MyPyramid and MODERATION
• Each food group narrows
toward the top.
• The base represents foods with
little or no solid fats or added
sugars.
• Select foods from the
MyPyramid base more often.
• The narrowing top represents
foods higher in sugar and fat.
You can eat more of these if
you’re more active.
Calorie comparison: 1 (8 oz.) cup
milk
Fat Free
85
0
100
1%
20
125
2%
40
145
Whole
65
0
50
100
150
Approximate calories
Discretionary calories
Total calories
200
Would whole milk be near the TOP
or the BOTTOM of MyPyramid?
Whole milk would
be nearer the top
Fat-free milk would
be at the bottom
The Balance of Good Health
Fruit and
vegetables
Meat, fish and
Protein foods
© BNF 2005
Grains, breads,
cereals and potatoes
Foods containing fat
Foods containing sugar
Milk and
dairy foods
Bread, other cereals and
potatoes
This group provides
carbohydrate. This
is the main source
of energy.
It also provides
fiber.
6 to 11 Servings
© BNF 2005
Any food made from wheat, rice, oats, cornmeal, barley or another
cereal grain is a grain product. Bread, pasta, oatmeal, breakfast
cereals, tortillas, and grits are examples of grain products.
Grains are divided into 2 subgroups, whole grains and refined
grains.
Whole grains contain the entire grain kernel -- the
bran, germ, and endosperm.
Refined grains have been milled, a process that
removes the bran and germ. This is done to give
grains a finer texture and improve their shelf life.
© BNF 2005
Fruit Group and Vegetables Group
Servings:
Fruit 2 – 4
Vegetables 3 – 5
This group is one of
the main provider of:
• Vitamin A;
• Vitamin C;
• fiber.
© BNF 2005
Any vegetable or 100% vegetable juice counts as a member of
the vegetable group. Vegetables may be raw or cooked; fresh,
frozen, canned, or dried/dehydrated; and may be whole, cut-up, or
mashed.
Vegetables are organized into 5 subgroups, based on their
nutrient content. 1)Dark green vegetables 2)Orange vegetables
3)Dried beans and peas 4)Starchy vegetables 5)Other
© BNF 2005
Any fruit or 100% fruit juice counts as part of the fruit
group. Fruits may be fresh, canned, frozen, or dried, and
may be whole, cut-up, or pureed.
© BNF 2005
Milk and dairy foods
This is the main group
to provide calcium.
It also provides
Vitamin A & D.
2 to 3 Servings
© BNF 2005
All fluid milk products and many foods made from milk are
considered part of this food group. Foods made from milk that
retain their calcium content are part of the group, while foods
made from milk that have little to no calcium, such as cream
cheese, cream, and butter, are not part of this group.
For those who are lactose intolerant, lactose-free and lowerlactose products are available.
© BNF 2005
Meat, fish and
alternatives
2 to 3 Servings
This is the main group to
provide protein.
It also provides iron.
© BNF 2005
All foods made from meat, poultry, fish, dry beans or peas, eggs,
nuts, and seeds are considered part of this group. Dry beans and
peas are part of this group as well as the vegetable group.
Most meat and poultry choices should be lean or low-fat. Fish,
nuts, and seeds contain healthy oils, so choose these foods
frequently instead of meat or poultry.
© BNF 2005
Foods containing fat / sugar
This group provides
fat and sugar (a form
of carbohydrate).
Use Sparingly
© BNF 2005
Oils are fats that are liquid at room temperature, like the vegetable
oils used in cooking. Oils come from many different plants and
from fish.
Foods that are mainly oil include mayonnaise, certain salad
dressings, and soft (tub or squeeze) margarine with no trans fats.
Solid fats are fats that are solid at room temperature, like butter
and shortening. Solid fats come from many animal foods and can
be made from vegetable oils through a process called
butter
hydrogenation. canola oil
© BNF 2005
corn oil
cottonseed oil
olive oil
safflower oil
soybean oil
sunflower oil
beef fat
chicken fat
pork fat (lard)
stick margarine
shortening
Physical activity simply means movement of the body
that uses energy. Walking, gardening, briskly pushing a
baby stroller, climbing the stairs, playing soccer, or
dancing the night away are all good examples of being
active. For health benefits, physical activity should be
moderate or vigorous and add up to at least 30
minutes a day.
© BNF 2005
http://www.cfsan.fda.gov/~comm/vltlabel.html
Food Labels:
What Do They
Mean?
© BNF 2005
1. www.calorieking.com
2. www.caloriesperhour.com
3. www.mypyramid.gov
© BNF 2005
Serving size:
•Basis for reporting each foods
nutrition content
•Amount of food customarily eaten at
one time
•Servings Per Container: Total servings
in the entire food package/container
% Daily Value:
•Percent of the nutrient the food contains
based on a 2000 calorie/day diet
•Helps to know how a food fits into the diet
http://www.cfsan.fda.gov/~dms/foodlab.html#see4
© BNF 2005
Nutrition Facts
Serving Size (1oz.) (7 Chips)
Servings per Container (7oz.) (49 Chips)
Calories 140 (585 kJ)
Calories from Fat 30
% DV
Total Fat
7g
11%
- Sat. Fat
1g
5%
- Trans Fat
0g
Cholesterol
0mg
0%
Sodium
115mg
5%
Total Carbohydrates
19g
6%
- Dietary Fiber
2g
8%
- Sugars
0g
Protein
2g
Nutrition facts panel – shows the amount of each
nutrient per serving
•Calories – total Food energy per serving
•Calories from fat – total Food energy per serving
from fat
•Fat – based on 30% of total calories
•Saturated fat – based on 10% of total calories
•Carbohydrate – based on 60% of total calories
•Protein – based on 10% of total calories
•Fiber – based on 11.5 grams/1000 calories
consumed
Nutrition panel footnote – reinforces the
fact that the % daily values are based on
a 2000 or 2,500 calorie diet
New Trans Fat Addition
Effective January 1, 2006, the
amount of trans fat in foods was
added to the nutrition facts label.
•The addition is due to the adverse
effects trans fatty acids have on
blood cholesterol levels.
•FDA will require that that the amount
of trans fatty acids be limited wherever
saturated fat limits are placed on
nutrient content claims, health claims,
or disclosure and disqualifying levels.
http://www.cfsan.fda.gov/~dms/flquiz1.html
© BNF 2005
2% Milk
© BNF 2005
Nonfat Milk
© BNF 2005
Cellular Respiration
The point of cellular respiration is to harvest electrons from
organic compounds such as glucose and use that energy to
make a molecule called ATP. ATP in turn is used to provide
energy for most of the immediate work that the cell does. ATP can
be thought of as being like a small package of energy that has just
the right amount of energy that can be used in a controlled
manner.
Types of cellular respiration
There are two basic types of cellular respiration aerobic cellular
respiration and anaerobic cellular respiration. Aerobic respiration
requires the use of oxygen and anaerobic respiration which does
not use oxygen.
© BNF 2005
© BNF 2005
© BNF 2005
Aerobic Respiration
Aerobic respiration is the process by which ATP is produced by
cells by the complete oxidation of organic compounds using
oxygen . In aerobic respiration oxygen serves as the final electron
acceptor, accepting electrons that ultimately come from the
energy rich organic compounds we consume. We will use
glucose as an illustration of an organic molecule used in cellular
respiration since glucose is a common energy source for cells. In
this figure the energy rich molecules (and heat) are in red, energy
poor molecules (relatively speaking) are in black. There are three
stages of aerobic respiration 1)Glycolysis 2)Krebs Cycle
3)Electron Transport Chain
© BNF 2005
Photosynthesis vs. Cellular
Respiration
© BNF 2005
Photosynthesis
Cellular
Respiration
Function
Captures energy
Releases energy
Location
Chloroplasts
Reactants
Carbon dioxide &
water
Cytoplasm &
Mitochondria
Glucose & oxygen
Products
Glucose & oxygen
Carbon dioxide &
water
Equation
CO2 + H20 + light energy
 C6H12O6 + O2
C6H12O6 + O2 
CO2 + H20 + energy
(ATP)
WHAT ARE THE SIX
NUTRIENTS?
CARBOHYDRATES
FATS
PROTEINS
VITAMINS
MINERALS
WATER
© BNF 2005
Simple
© BNF 2005
Complex
Carbohydrates
• Carbohydrates are a main source of
energy for the body and are made of
carbon, hydrogen, and oxygen.
• Most carbohydrates have a ratio of 1:2:1
of carbon, hydrogen, and oxygen.
• Should provide 55 - 60% of calories in
American diet
• Complex carbohydrates (needed in diet!)
– Large molecules, Starches
– Fibers
• Simple carbohydrates (watch it!)
– Monosaccharides
– Disaccharides
© BNF 2005
Functions of Carbohydrates
• Energy (glucose)
– 4 Calories/g
• Make up many
macromolecules
– RNA, DNA
• Found on cell
surfaces as part of
signal systems for
proper function of
cells
© BNF 2005
Most Common
Monosaccharides
in the Diet
• Galactose
– Does not occur in diet as monosaccharide
– Most often a part of lactose, milk sugar
• Fructose
– Fruits, veggies, honey
• Glucose
– Most important source of energy
– Usually occurs in disaccharide or starch
© BNF 2005
Monosaccharides
© BNF 2005
Simple Carbohydrates
• Sugars: 21% of American diet
• Sugars added to food as sweetner
– Sucrose is refined from sugar beets,
sugar cane
– Other processed sugars: honey, maple
syrup, brown sugar, molasses
• Sugars added in food manufacturing:
• Sucrose, fructose, high-fructose corn
syrup, corn syrup, maltose
© BNF 2005
Most Common Disaccharides
• Maltose
– Glucose + glucose
– Sweet taste of bread (amylase)
• Sucrose
– Table sugar
– Glucose + Fructose
– Sugar in food labels
• Lactose
– Only sugar found in animal food
– 30% of energy in cow’s milk
– Galactose + Glucose
© BNF 2005
Constructing Disaccharides
© BNF 2005
Complex Carbohydrates in
Diet
• 3 Types of Complex Carbohydrates
- Glycogen (Stored glucose), Starch (amylose and
amylopectin), Fiber (Soluble and Insoluble)
• Grains
– Rice, corn, oats, wheat, barley
• Legumes (pods with rows of seeds)
– Peas, lentils, soybeans, kidney beans (starchy
seeds)
• Vegetables
– Tuber veggies: sweet & white potatoes, yams,
– Veggies such as green beans, broccoli have small
amount of starch, lots of vitamins, fiber, minerals.
© BNF 2005
Complex Carbohydrates
• Consist of many monosaccharides
• Oligosaccharides (3-10 mono)
– Found in beans & other legumes
– Cannot be digested by humans
– May cause gas and discomfort (Bean-O)
• Polysaccharides
– Glycogen stored in muscles, liver
• Terminal mono is removed; quick energy supply
– Starch stored in plants (amylose and
amylopectin)
– Fiber, Cellulose structural part of plants
© BNF 2005
Complex Carbohydrates
Cont. Dietary Fiber
• Plant materials that cannot be digested
• Insoluble fibers
– Not soluble in water
– Cellulose, hemicellulose, lignin
– Wheat, rye bran; celery, broccoli
• Soluble fibers
– Dissolve in or absorb water
– Pectins, gums
– Oats, apples, beans, psyllium (used in bulkforming laxatives like Metamucil)
© BNF 2005
Cellulose
© BNF 2005
Stored Carbohydrates
© BNF 2005
© BNF 2005
FATS
UNSATURATED
© BNF 2005
SATURATED
• Lipids are organic substances consisting mostly of
carbon and hydrogen atoms.
• There are three families of lipids: (1)Triglycerides,
(2) phospholipids, and (3) sterols.
• Fatty acids and glycerol make up the larger molecule
of fats. A fatty acid consists of a long carbon skeleton of
16 or 18 carbon atoms, though some are even longer.
• Triglycerides are the basic unit of fat and are
composed of three ("tri-") fatty acids individually bonded
to each of the three carbons of glycerol.
© BNF 2005
Glycerides
The major
form of
lipid in
food and
in the
body
© BNF 2005
• Saturated fatty acids have single bonds between the carbon
atoms that make up the tail. The carbon atoms are "full" or
saturated, and therefore cannot take up any more hydrogen. Most
animal fat, such as butter, milk, cheese, and coconut oil, are
saturated.
• Unsaturated fatty acids have one or more double bonds
between carbon atoms. A double bond is the sharing of four electrons
between atoms, while a single bond is the sharing of two electrons.
• Monounsaturated fatty acids contain only one double bond,
such that each of the carbon atoms of the double bond can bond with
a hydrogen atom. An example of monounsaturated fatty acids is oleic
acid, which is found in olive oil.
• Polyunsaturated fatty acids contain two or more double bonds,
such that four or more carbon atoms can bond with hydrogen atoms.
Most vegetable fats are polyunsaturated fatty acids.
© BNF 2005
Types of Fatty Acids
© BNF 2005
Adipose Tissue
Fat stored in this cell
© BNF 2005
Function of Lipids
• Immediate source of energy
• Stored form of energy (85% triglycerides)
• Protection and cushioning
– Eye sockets, heart valves, kidneys, fatty
apron
• Insulation (temperature regulation)
© BNF 2005
Function continued
• Structural part of cell membranes
(phospholipids, cholesterol)
• Regulation
– Cell communication, neurotransmitter
synthesis
– Bile salts (from cholesterol),
– Hormones (from cholesterol)
– Prostaglandins, eicosanoids (from
omega-3 & omega-6 fatty acids)
© BNF 2005
Hydrogenated Fats
• Hydrogenation of vegetable oils
converts some of unsaturated bonds
to saturated, trans conformation.
• Trans fatty acids extend shelf life,
improve margarine, shortening.
• Diet high in trans fatty acids risks
heart disease, cancer.
© BNF 2005
© BNF 2005
Trans Fatty Acids
The Truly Awful!
© BNF 2005
The
Good!
© BNF 2005
Sterols
• Cholesterol:
– 90% is found in
cell membranes
– Produced by the
liver
– Associated with
cardiovascular
disease
– Produced by
animals only.
None found in
plants.
© BNF 2005
• "Bad" cholesterol is the low-density lipoprotein (LDL), the
major cholesterol carrier in the blood. High levels of these LDLs
are associated with atherosclerosis (heart disease) .
• "Good" cholesterol is the high-density lipoprotein (HDL); a
greater level of HDL--think of this as drain cleaner you pour in the
sink--is thought to provide some protection against artery
blockage.
• The levels of HDL, LDL and total cholesterol are all indicators
for atherosclerosis and heart attack risk.
• People who have a cholesterol level of 275 or greater (200 or
less is desirable) are at significant risk for a heart attack, despite a
favorable HDL level.
© BNF 2005
Phospholipid
Lecithin, a
common food
additive, is a
phospholipid.
Embedded in
cell
membranes.
© BNF 2005
PROTEINS
© BNF 2005
• Proteins are compounds composed of carbon,
hydrogen, oxygen, and nitrogen, which are arranged
as strands of amino acids.
• They play an essential role in the cellular
maintenance, growth, and functioning of the human
body. Serving as the basic structural molecule of all the
tissues in the body, protein makes up nearly 17 percent
of the total body weight.
•The recommended protein intake for an average adult
is generally based on body size: 0.8 grams per
kilogram of body weight is the generally
recommended daily intake. Approximately 15 – 20% of
daily calories should come from proteins.
© BNF 2005
Proteins are vital to basic cellular and body functions,
including cellular & tissue regeneration/repair,
hormone and enzyme production, fluid balance, and
the provision of energy.
1. Cellular & Tissue regeneration/repair: The body is
constantly undergoing renewal and repair of tissues. The
amount of protein needed to build new tissue or maintain
structure and function depends on the rate of renewal
2. Hormone & Enzyme production: Amino acids are the
basic components of hormones, which are essential
chemical signaling messengers of the body. Hormones are
secreted into the bloodstream by endocrine glands
© BNF 2005
3. Fluid Balance: The presence of blood protein
molecules, such as albumins and globulins, are critical
factors in maintaining the proper fluid balance
between cells and extracellular space.
4. Energy Provision: Protein is not a significant source
of energy for the body. Protein yields as much usable
energy as carbohydrates, which is 4 Cal/gm (Calories
per gram). Although not the main source of usable
energy, protein provides the essential amino acids that
are needed for adenine, the nitrogenous base of ATP,
as well as other nitrogenous substances, such as
creatine phosphate
© BNF 2005
• Amino acids are the fundamental building blocks of protein.
Long chains of amino acids held together by peptide bonds,
called polypeptides, make up the multicomponent, large
complexes of protein.
•The arrangement of amino acids along the chain determines
the structure and chemical properties of the protein.
•Amino acids consist of the following elements: carbon,
hydrogen, oxygen, nitrogen, and sometimes sulfur.
•The general structure of amino acids consists of a carbon center
and its four components, which consists of an amino group
(NH2), an organic acid (carboxyl) group (COOH), a hydrogen
atom (H), and a fourth group, referred to as the R-group, that
determines the structural identity and chemical properties of the
© BNF 2005
amino acid.
• There are twenty different forms of amino acids that the human
body utilizes. These forms are distinguished by the fourth variable
component, the R-group, which can be a chain of different
lengths or a carbon-ring structure.
• If Hydrogen represents the R-group, the amino acid is known
as glycine, while a methyl (CH3) group is known as alanine.
Thus, the chemical components of the R-group essentially
determine the identity, structure, and function of the amino acid.
© BNF 2005
(Functional
Group)
© BNF 2005
Alanine
Arginine
Aspartic Acid
Asparagine
Cysteine
Glutamic Acid
Glutamine
Glycine
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Proline
Serine
Threonine
Tryptophan
Tyrosine
Valine
Of the twenty amino acids, eleven are considered
nonessential (or dispensable), meaning that the body is
able to adequately make them.
Nine are essential (or indispensable), meaning that the
body is unable to adequately make them to meet the
needs of the cell. They must therefore be supplied
through the diet.
Foods that have protein contain both nonessential and
essential amino acids, the latter of which the body can
use to synthesize some of the nonessential amino acids.
© BNF 2005
• The quality of protein depends on the level at which it
provides the nutritional amounts of essential amino acids
needed for overall body health, maintenance, and growth.
Animal proteins, such as eggs, cheese, milk, meat, and fish,
are considered high-quality, or complete proteins because
they provide sufficient amounts of the essential amino acids.
• Plant proteins, such as grain, corn, nuts, vegetables and
fruits, are lower-quality, or incomplete proteins because
many plant proteins lack one or more of the essential amino
acids, or because they lack a proper balance of amino acids.
Incomplete proteins can, however, be combined to provide all
the essential amino acids as long as they are eaten together at
the same time of the meal.
© BNF 2005
© BNF 2005
© BNF 2005