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NUTRITION
We already know that our food provides us with energy- what else does it provide us
with? Amino acids or 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
Fats
Proteins
Water
Vitamins
Minerals
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
and carrying fat-soluble vitamins.
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, severe power weight
training). Excess protein can not be stored in the body, and if you eat
more than you need it is 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.
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. Unfortunately the typical American diet is closer to 60% for fat and sugar
combined. 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. 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, and nuts.
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.
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), monosaturated fats (found in olives and
avocados) and polyunsaturated (fish and vegetable oils). Saturated fats are the “bad” ones
which, in excess, may lead to high cholesterol levels in the blood and increase the chance
of coronary disease. Mono and polyunsaturated may not clog your arteries, but they are
still fattening! All fats have the same number of Calories per gram. Only 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 actually 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 a day? 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)
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
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 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 look at the back of a box of Kellogg’s Corn Flakes:
In each serving (1 oz) there are:
100 Calories, 2 grams of protein, 24 grams of carbohydrate and 0 grams of fat.
2 g protein x 4 Cal/g protein = 8 Cal from protein
8 Cal from protein divided by 100 total Calories = 8% Calories from protein*
24 g carbo x 4 Cal/g carbo = 96 Calories from carbohydrates
96 divided by 100 = 96% Calories from carbohydrates.*
*(Note that since these numbers are approximations, they don’t quite add up to 100%)
Only 2 of the 24 grams of carbohydrate come from sugar. Looks like a pretty good thing to eat.
Now let’s look at a box of Quaker 100% Natural Cereal:
130 Calories in a serving (1 ounce, but only 1/4 of a cup!), 3 g of protein, 18 g of
carbohydrates (8 of them complex, 8 simple and 2 of fiber), 5 g of fat.
Calories from protein = 15 or about 11%
Calories from carbos = 72 or 55%, but half are from simple sugars
Calories from fat = 45 or 35% !
Perhaps not such a good choice after all. 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 optimal healthy diet for you.