Download Our food provides us with energy- what else does it provide us with

PPT
Nutrition
Developer Notes
Goals
Discuss nutrition
Understand metabolic needs
Concepts & Skills Introduced
Area
Physiology
Physiology
Concept
Classes of nutrients
Diet adequacy
Time Required
One class period
Warm-up Question
What’s in the food we eat?
Presentation
You can use the warm-up question to start the discussion on classes of nutrients.
A good activity is to have the students bring in and analyze food labels.
This reading is a follow-up to the reading on energy needs in the body.
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Nutrition
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Nutrition
Reading
NUTRITION
We already know that our food provides us with energy - what else does it provide us with?
Amino acids (which are the building blocks for proteins), vitamins, and minerals are all
necessary to body building and maintenance. A healthy diet provides enough energy and other
things you need to build and maintain your body.
Everything you eat is made up of some combination of these things:
Nutrient Class
Carbohydrates
Lipids (Fats &
oils)
Proteins
Water
Vitamins
Minerals
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Function
Serve as the primary source of energy for biological work. The
muscular system and the brain rely almost solely on carbohydrates.
There is a limit to how much carbohydrate (in the form of glycogen)
you can store in your body. Excess carbohydrates are stored as fat.
Provide the most energy-rich chemical bonds, but are more difficult
to break down. They are considered a secondary source of energy.
Fats are easily stored in the body. Stored fat does have several
valuable purposes, including cushioning organs, providing insulation,
carrying fat-soluble vitamins, and providing an extra store of energy
for when you're sick or can't get food.
Essential for maintenance, growth and repair of cells. Proteins are
made up of long chains of amino acids. There are 20 different amino
acids and the body is able to synthesize 11 of these. The remaining 9
must be consumed in your diet. Protein is only used as an energy
source in extreme conditions (e.g., starvation, extreme weight
training). Excess protein can not be stored in the body, and if you eat
more than you need it is converted to lipids and stored as fat.
40-60% of your body is water. It is necessary to stabilize body
temperature, carry nutrients, including water-soluble vitamins, and
waste products. It is essential for all cell functions.
Regulate chemical reactions in the body and are needed for tissue
synthesis. They are classified as either water or fat-soluble. Not
enough or excess of some vitamins can cause illness or even death.
Vitamin deficiencies are rare when eating a balanced diet.
Regulate body processes and form some structures in the body (e.g.,
the bones are made predominantly of calcium). Needed for enzyme,
hormone and some vitamin functioning. Excess consumption is
useless and sometimes toxic to the body. Many minerals are needed
in very small amounts, are re-usable, and deficiencies (with the
exception of calcium and iron) are rare.
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Nutrition
A balanced diet can provide all of these things for you. Current nutrition research recommends that 60%
of the calories you consume should come from carbohydrates, only 25% should be fat and 15% protein.
This is where most people need to make the changes in their eating habits.
Many people get stressed out at the thought of trying to put together a balanced diet, but it can be
pretty easy if you have the right information!
How many calories you can consume in a day without gaining or losing weight depends on your level of
activity and your metabolism. Average daily metabolic rates for people who only do light activities are
as follows:
Cal
Age
expended/day
Males
Females
15 - 18
2800
2200
19 - 22
2900
2100
23 - 50
2700
2000
51 - 75
2400
1800
These numbers are considerably higher for a very active person- it can be closer to 5000 Cal/day
for males and 3500 Cal/day for females. You’d be surprised, however, just how hard you do
have to work to burn those extra calories. For example, running a 26.2 mile marathon only burns
about 2800 Calories. That’s not even one pound of fat! (A pound of fat is the equivalent of 3500
Calories). So, if you want to lose weight you’re better off not eating dessert than thinking you’ll
burn it off jogging around the block - you’d be jogging a very long time.
Counting calories is a drag. There are easier ways to watch what you eat without getting fanatical
about everything that goes in your mouth. The easiest rule of thumb is to have 1-2 servings from
the meat group, 2-3 from the dairy group, and 2-4 servings of fruit, 4-6 of vegetables/bean, and
6-11 in the cereal/bread group. (See below for serving sizes.) We’ve all seen the famous food
pyramid. You can use it to your advantage when planning a healthy diet.
Carbohydrates. The highest proportion of foods in your diet should come from this group- 6 to
11 servings per day. These foods provide a valuable energy source in the form of complex
carbohydrates (starches). They are also loaded with vitamins, minerals, and fiber. Fiber is critical
to maintaining digestive health, and high-fiber diets have recently been found to reduce the risk
of some kinds of cancer, especially colon cancer.
Vegetables- You should eat 3-5 servings of vegetables per day. Vegetables provide vitamins like
A and C, and folate. They also provide minerals like iron and magnesium and fiber. Dark green
leafy vegetables like spinach are a nutritionally rich food.
Fruits- 2-4 servings of fruit are recommended per day. These are important sources of Vitamins
A and C, and also some fiber. Fruits have natural sugars, or simple carbohydrates, and can
provide a sweet alternative to higher-fat sugar desserts.
Meat/Protein- Meat, poultry, and fish supply protein, along with B vitamins and iron and zinc.
You should consume 2-3 servings per day. If you do not eat animal foods, you can choose
alternates from this group like beans, soy, and nuts.
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Dairy- Milk products provide protein and vitamins, especially vitamin D, but also minerals like
calcium. Most people need to consume 2 servings of milk, cheese, yogurt, or other dairy
products like ice cream (just watch out for fat and sugar) daily. Because calcium is so critical to
bone development, young people under 24 should have 3 or more servings daily. Alternative
sources of calcium are dark green leafy vegetables, tofu (made with calcium sulfate), and
calcium fortified foods.
Fats, oils, and sweets- These foods are at the top of the pyramid, and should be used very
sparingly. Simple carbohydrates - sugars, provide lots of energy, but no other nutritional value
and are often considered “empty calories”. There are 3 kinds of fats: saturated fats (found mostly
in meat and dairy products), monounsaturated fats (found in olives and avocados) and
polyunsaturated (fish and vegetable oils). Saturated, in excess, may lead to high cholesterol
levels in the blood and increase the chance of coronary disease. Mono- and polyunsaturated may
not lead to clogging your arteries, but they are still fattening! All fats have the same number of
Calories per gram. Approximately 25% of your calories should come from fat. You can cut the
fat calories if you are trying to lose weight, but you still need some in your diet for the reasons
we described earlier.
Once you have the facts about the food groups, the only thing you have to be concerned about is
how big a serving really is. That’s where most people blow it. Read the box of cereal and it tells
you there are 110 Calories in a serving. Yes, there are, but a serving is one ounce or one cup and
most people fill a bowl that holds closer to one and a half cups. Do you have a good idea about
how many ounces of meat you eat daily? Your typical plate lunch has your entire quota of
protein for the day!
The following provides some guidelines for serving sizes in the different food groups.
Average serving sizes:
milk/yogurt - 1 cup
cheese - 2 ounces (one sandwich size slice)
meat/poultry/fish - 2 or 3 oz (about the size of your palm or a deck of cards)
bread - 1 slice
dry cereal - 1 ounce (1/2 - 3/4 cup of non-granola cereals)
pasta/rice - 1/2 cup
vegetables - 1/2 cup cooked or raw or 1 cup raw, leafy
fruit - 1 piece or 1/2 cup cooked or canned
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Reading a nutrition label is a good skill to have when trying to plan your diet. There’s a lot of
information there if you know how to decipher it. Labels are required by law to break down the contents
into grams of protein, fat and carbohydrate as well as what type of fat or carbohydrate. To figure out
what percentage of calories is coming from each category you need some simple math. There are
approximately 9 Calories in a gram of fat, 4 Calories in each gram of carbohydrate or protein. So let’s
compare two cereals, Kellogg's Corn Flakes and Quaker 100% Natural Cereal.
Kellogg’s Corn Flakes
100 Calories per serving. 2 grams of protein, 24 grams of carbohydrate (21 g complex, 2 g sugar, 1
g fiber) and 0 grams of fat.
Calories from protein =
2 g  4 Cal/g = 8 Cal, or about 8% *
Calories from carbos =
24 g  4 Cal/g = 96 Cal, or 96% * (8% from sugars)
Calories from fat =
0 Cal, or 0%
* Since these numbers are approximations, they don’t quite add up to 100%.
Quaker 100% Natural Cereal
130 Calories per serving (1 ounce, but only 1/4 of a cup!), 3 g of protein, 18 g of carbohydrates (8
g complex, 8 g sugar, 2 g fiber), 5 g of fat.
Calories from protein =
Calories from carbos =
Calories from fat =
3 g  4 Cal/g = 12 Cal, or about 9%
18 g  4 Cal/g = 72 Cal, or 55% (44% from sugars)
45 Cal, or 35% !
Looks like the Corn Flakes might be a better choice than the Natural Cereal. Beware of labels
that say things like “natural”— sugar and fat are both completely natural ingredients, and
advertisers know what ploys to use to make you feel good about buying their products. Be aware,
too, of labels that claim to be ”light” or “low fat”. Light means different things for different
foods. Either the food starts out fatty and half of the fat has been removed or the calorie content
has been cut by 1/3. So something like bacon which normally gets 80% of its calories from fat
may only have 40% if it’s “light”, but still high in fat! “ Low fat” on a label means no more than
30% of the calories come from fat. But if everything you ate had this percentage of fat you
would still get more than the recommended daily percentage of calories from fat.
Activity:
The United States Department of Agriculture and the Center for Nutrition Policy and Promotion have
developed a system for rating your diet. Follow the directions on the worksheet, and use the table to help
you sort out how many servings of each group and grams of fat you need. You can compare your diet to
the typical healthy diet for someone like you.
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