Wednesday, 8 June 2011

Understanding Glycemic Index and Glycemic Load

In my daily research on how to deal with my PCOS, improve my health and lose weight the healthy way, I have come across various health issues and concerns, including diverse methods on how groups and individuals deal with them, food and its nutritional values, and  different types of diets, fad or not, healthy or not, high-maintenance or not.  I have also learned that taking out a certain food group in ones diet is unhealthy.

Some diets are low if not totally discourages the consumption of carbohydrates in their meals.  Of course one cannot totally take it out from his/her diet because carbohydrate is present in most fruits and vegetables.  Carbohydrate is one of the building blocks of food, same is true with fats and protein.  Not consuming one of this three is equivalent to imbalance diet which leads to deficiencies, diseases, bad health. Also, high or low consumption of carbohydrate is not all good nor bad.  This is where the concept of GI (Glycemic Index) and GL (Glycemic Load) comes in.

Let me share what I have understand so far, please correct me if I am wrong on some points and share those which I missed.

According to http://en.wikipedia.org, “The glycemic index, glycaemic index, or GI is a measure of the effects of carbohydrates on blood sugar levels. Carbohydrates that break down quickly during digestion and release glucose rapidly into the bloodstream have a high GI; carbohydrates that break down more slowly, releasing glucose more gradually into the bloodstream, have a low GI”

In my layman’s understanding, GI is the measurement of how fast carbohydrates affect blood sugar level after consumption.  In which  carbohydrate-rich food is measure on a scale from 0 to 100 according to the rate  to which they raise blood sugar levels over 2 -3 hours after eating certain such carbohydrate-rich food).  And high GI food are rapidly digested, turned to sugar, and absorbed by the blood and thus resulting to a sudden increase in blood sugar level. Due to their tendency to escalate blood glucose levels at a quick rate, high glycemic foods can be detrimental to health, especially in the long-run (http://www.all4naturalhealth)  Low-GI foods, on the otherhand, have the opposite effect, due to their slow digestion, it takes time to convert carbohydrate to sugar, which leads to slower absorption, thereby producing a gradual rise in blood sugar and insulin levels.

What do we get / benefit from low GI foods, health wise?  To answer that, I have to share the effects of too much consumption of high GI foods.  Ingesting a lot of high GI food coupled by a sedentary life is detrimental to ones health because:  High GI food causes serious weight problems (excess sugar is converted to fat and stored in the body); it reduces the body’s sensitivity to insulin, degenerate the pancreas, leads to atherosclerosis (due to high triglyceride level in the blood), which contributes to the development of cardiovascular diseases and increases the risk of heart attack and stroke; it also leads to nerve diseases and hypertension; as well as eye and kidney diseases.

You got the picture? Low GI food does the opposite effect.

-    Low GI foods are good for people with diabetes as it helps to control and manage their conditions by reducing insulin levels and insulin resistance.  It also lowers the risk of getting type 2 diabetes.

-    It is also good for those people like me who wants to lose and manage weight as  low GI food help control appetite, reduce hunger, and keep one fuller for longer thus delaying the need to eat.

-    Increase and maintain the body's sensitivity to insulin

-    It reduces the risk of heart diseases

-    Helps improve blood cholesterol level

-    Helps control triglyceride / lipid levels in the blood thereby reducing the risk of developing atherosclerosis and thus preventing heart attacks and strokes

-    Prevents and manage hypertension

-    Decreases the risk of cancer which are associated with regular and excess consumption of high GI processed foods.

-    prolongs physical endurance as blood glucose levels are kept at a moderate level (instead of dipping drastically due to sudden insulin production) for a more sustained period of time. It also help re-fuel carbohydrate stores after exercise

-    Most importantly, it helps manage the symptoms of PCOS (polycystic ovary syndrome).

Classification


GI range


Examples

Low GI 55 or less most fruits and vegetables, legumes/pulses, whole grains, nuts, fructose and products low in carbohydrates
Medium GI 56–69 whole wheat products, basmati rice, sweet potato, sucrose
High GI 70 and above baked potatoes, watermelon, white bread, most white rices, corn flakes, extruded breakfast cereals, glucose, maltose

Source :  http://en.wikipedia.org

However, it is also not all true that excessive consumption of High GI food is bad to the health and there is also a risk with too low GI consumption, according to one article by http://www.whathealth.com , in which excessive low GI intake  can lead to inadequate nutrition if the focus is exclusively on consuming low glycemic index foods. This could result in a calorifically high diet, rich in fat, low in carbohydrates and low in fiber.

To balance carbohydrate intake or for better dietary practice,  glycemic load (GL) needs to be considered also. As defined by www.whathealth.com, glycemic load (GL) is a measurement which ranks the impact of food carbohydrates on blood glucose levels. However the key difference between GI and glycemic load is that glycemic load reflects a specific foods glycemic index and portion size.In essence glycemic load takes into account both the quality and quantity of the foods carbohydrates.

Here’s the Glycemic Load Formula by www.whathealth.com

              GL = GI / 100 x CHO* (grams) per serving CHO = carbohydrate content

For example: the glycemic load of a medium sized apple which has 15 grams of carbohydrate 40 /100 x 15 = 6

In my layman’s understanding  the effect of carbohydrate in the blood glucose is affected not only by a foods GI content but also the amount of food intake for that particular food thus the GL.  So it is alright to eat high GI food provided it is in small amount/portion size only and low GI foods in larger portions / quantities in order to regulate GL.   It is very important to consider these two factors, GI & GL, to better understand the effect of food on our blood sugar in order to better manage it.
Low GL 10 or less
Medium GL 11- 19
High GL 20 or more

Source :  http://en.wikipedia.org

Glycemic load (GL) per day (http://www.healthiertalk.com/beyond-carb-wars-049 )
Low GL  Less than 80
High GL 81 or more

Some diet programs recommends intake of not more than 40 GL per day in order for an individual to lose weight. So shall we start counting those GIs and GLs?

-Foodformylove(8June2011)



Sources and further readings :

1) http://en.wikipedia.org/wiki/Glycemic_index

2) http://en.wikipedia.org/wiki/Glycemic_load

3) http://www.all4naturalhealth.com/low-glycemic-diets.html

4) http://www.whathealth.com/glycemicindex/lowgi.html

5) http://www.whfoods.com/genpage.php?tname=faq&dbid=32

6) http://www.glycemicindex.com/

7) http://www.healthiertalk.com/beyond-carb-wars-049

http://www.health.harvard.edu/newsweek/Glycemic_index_and_glycemic_load_for_100_foods.htm

No comments:

Post a Comment