What is the Glycemic Index?
by Gary Matthews
Maximum Fitness
Over the last 30 years, research
into food and blood glucose response has completely changed our carbohydrate
classification system.
It has been learned that
it is impossible to predict the impact on blood glucose levels by certain
foods, instead people are fed carbohydrate foods and the response measured.
This response is known as
the Glycemic Index (GI). It is a measure of how quickly carbohydrate foods
are digested and absorbed and ranks carbohydrate foods according to their
impact on blood sugar (glucose) levels, as indicted by elevated blood glucose.
Foods with a high GI are
absorbed quickly into the blood stream and cause a rapid rise in blood
glucose levels. Foods with a low GI are broken down more slowly over time
and keep blood glucose levels more stable (Remember that low is slow!).
Some carbohydrate foods will
maintain your energy levels for hours, while some may cause your blood
glucose to rise and fall. Different types of carbohydrates can also affect
feelings of fullness in the stomach and this can influence hunger and your
ability to control your body weight.
Why is the GI important?
When our blood glucose levels
are stable we have plenty of readily available fuel for the brain and muscles.
If our blood glucose levels drop too low (hypoglycaemia) we feel tired,
dizzy and generally unwell. If our blood glucose levels rise too quickly
a rapid drop usually follows this.
Include low glycemic index
foods in meals and snacks to slow the release of glucose into the bloodstream.
A low glycemic index snack a few hours before exercise will help maintain
your energy levels for more effective training.
After high intensity exercise
(strength training) a high glycemic index snack should be consumed within
30 minutes. This will help to replace energy and start the recovery process.
Low-GI foods take longer
to digest and help delay hunger pangs that little bit more and thus promote
weight loss. So please choose your carbs carefully as this will lower your
insulin levels and burn more fat. The secret is to swap high GI foods with
low GI foods.
Simple steps to a low
GI diet.
Step No 1
Start with a healthy, well-balanced
and varied diet based on a good nutrition program. The diet should be low
in fats, moderate in carbohydrate and protein. The program should be high
in fibre and contain a varied amount of foods to provide the required amount
of vitamins and minerals.
Step No 2
Look at the type of carbohydrates
that you consume during the day. Look at the carbs that you eat the most,
as these will have the most dramatic impact on your diet.
Try to change the carbs you
eat the most with at least one low GI one. (Replace potato with sweet potato,
use noodles instead of rice). By substituting half of your daily carbohydrate
from high GI to low GI will result in an overall reduction in the GI of
your diet.
Reducing the GI in your diet
reduces your insulin levels and increases the fat burning apparatus in
your body. Try to reduce the high GI's in your diet by substituting them
with low GI's.
Regular consumption of low
GI foods increases the feelings of fullness and satisfaction and so prevents
weight gain. Try taking in six small meals a day of healthy low fat low
GI foods to prevent overeating at meal times and control appetite.
Remember, that it is also
important to look at the calories in food to. Rice and bread might be low
in fat but when your body is burning the carbohydrates in these foods,
it doesn't burn as much fat. So if you are on a low fat diet, you wont
lose as much weight if your calories are still high.
Have a look at the table
below for the different GI food ratings.
Low GI (<50)
Medium GI (50-70) High GI (70>)
Grapefruit (26)
Pineapple (66) Cornflakes (80)
Baked Beans (15) Raisins
(64) W/M Bread (72)
Lentils (29)
Sweet corn (59) Brown Rice (80)
Peanuts (13)
Potato Chips (51) Carrots (92)
Soy Beans (15)
All bran (51)
Baked Potato (98)
Compare these two menus and
try to adjust your diet accordingly.
High GI Menu
Breakfast: 40
Grams of cornflakes with milk. Two slices of whole meal toast with margarine
and jam.
Snack: Two sweet
biscuits with a white coffee.
Lunch: Ham and
salad whole meal roll with an apple.
Snack: Four crackers
with cottage cheese and chives.
Main Meal: Serving
of roast chicken with a large baked potato and peas. Small piece of cake.
Low GI Menu
Breakfast: 40 Grams
of bran with low fat milk. Two slices of low GI toast (Try Burgen) with
margarine and jam.
Snack: Two oatmeal
biscuits with a coffee (Low fat milk).
Lunch: Ham and salad
Roll (Low GI bread). Soft-serve vanilla yoghurt with toasted muesli sprinkled
on top.
Snack: Two bananas.
Main Meal: Serving
of Roast chicken with a small baked potato and peas. Two scoops of low
fat ice cream with half a cup of canned peaches.
Chicken, beef, fish, eggs,
nuts, and avocados contain very little or no carbohydrates. These foods
if eaten by themselves will not have much effect on your glucose levels
and are very low GI. Alcoholic beverages especially wine are also low GI
so can be included in your diet but remember to count them in your daily
caloric intake.
Low GI foods are ideal for
losing weight due to the slow absorption from the stomach. Low GI foods
also help to keep blood sugar levels more stable and this has an effect
on reducing sweet cravings.
Gary is the author of several
ebooks, including "Maximum Weight Loss in Ten Weeks" - the complete ebook
and time-saving solution for burning away unwanted fat, and "Maximum Weight
Gain in Ten Weeks" - easy-to-use and follow techniques that serve as a
guide to muscle growth without having to "live in the gym".
Visit Gary's website at http://www.maximumfitness.com