The Glycemic index (GI) was conceived in 1981 by David Jenkins and fellow researchers, as a tool for the dietary management of Type 1 diabetes at the University of Toronto.
The Glycemic index shows you how quickly or how slowly a particular food especially carbs affect your blood sugar when you take it.
In other words when you eat a particular carbohydrate, say rice, what happens to your blood sugar?
Does it go up or does it remain stable?
Based on how it affects your blood sugar, the carbohydrate is assigned a number.
Some carbs make your blood sugar go up because they are so refined that it’s easy for your body to convert it to glucose, while others that are not refined are slower for your body to digest so it’s not easily converted to glucose.
This does not mean that only refined food have high GI.
Some natural foods also come with a high Glycemic index
Why is it important to know the GI of your carbs?
- Knowing and understanding the GI helps you to make the right choice when eating carbs. This way you will know the carbs that causes your blood sugar to go up whenever you eat them.
- Knowing the GI can help you in fat loss and in maintaining a healthy weight because you will know which food to avoid or minimize the intake. A study done in South Africa of obese females found that those eating a low GI diet lost 4 pounds more than females eating a high GI diet. (3, 12)
- It can help in preventing diseases like Diabetes and cardiovascular diseases.
What do the numbers mean?
It means that carbohydrates assigned the number from:
1 – 55 = Low (good)
56- 69 = Medium
70 or higher = High (bad)
Can the Glycemic index of a food change?
Yes, there are Factors that may change the Glycemic index of food from low to high
Some of those factors are:
Unripe – ripe: When banana is unripe the Glycemic index is low because it is mainly made up of resistant which cannot be digested in the small intestine. But when it ripens, the starch Is converted to sugar and this raises the GI.
Preparation: Cooking rice and pasta till its swollen and soggy increases the Glycemic index because it causes all the starch grain (the long chain of carbs) to burst and this makes it a lot easier for your body enzymes to break down the starch.
But when it’s cooked for a shorter time, it becomes harder for the enzymes in your body to break down the starch, so its effect on your blood sugar is low.
Added things: Adding things like salad dressing increases the Glycemic index of low GI vegetables
Method of cooking: Frying increase the Glycemic index of food.
A mixed meal alters the Glycemic index of a food. Whole milk has a low GI because it’s a combination of protein, carbs and fat.
When a particular food is eaten along with other foods, the blood glucose response and Glycemic index will vary, depending on the proportion of carbohydrate, protein, and fat in the mixed meal.
When fat is added to a carbohydrate meal, it decreases blood sugar response.
Fiber – Porridge oats has a lot of fiber and this slows down the absorption of the carbs into your blood.
Some foods and their Glycemic index
Click on the link to view – Document1.pdf GI TABLE.pdf 3
How can the Glycemic Index help in fat loss?
A food with high GI causes a rapid rise in your blood sugar. This gives you energy for a short time and then leaves you feeling weak, hungry and listless. This makes it more likely for you to over eat.
However, a food with low GI releases sugar slowly into your blood. This ensures that your blood sugar is stable. You’ll have a steady and stable supply of energy and feel full for a longer time.
When you feel full and satisfied, you’re less likely to go on a snacking spree, and that makes it less likely for you to overeat and gain fat.
There are some controversies regarding the GI.
The GI basically shows you the effect of a particular food on your blood sugar level; it does not tell you the effect of that same food on your blood sugar when it’s eaten with other foods.
From what you read above you already know that the GI of a particular food can be affected by other things.
Another thing is the so called ‘second meal effect’.
This is the impact that your previous meal has on your blood sugar and how it will affect it further when you take the next meal.
In conclusion Low GI can help in preventing and reducing the risk of Type 2 Diabetes and cardiovascular disease.
It can also help in fat loss. Vary your carbohydrate intake by choosing carbs rich in fiber and antioxidants
As with everything, learn balance. Don’t become so focused on the GI of food that it becomes your new fad diet.
Brand-Miller J, Wolever TMS, Foster-Powell K, Colagiuri S. The new glucose revolution. 2nd ed. New York: Marlowe & Company; 2003. 4. Ludwig DS. The glycemic index: physiological mechanisms