by Daniel Vane

Created on: November 13, 2007

Understanding the Glycemic Index: What is it, and how can it help me be healthy?

OK, we've heard all about it over the last two years, and it's used as an effective marketing tool. It's the latest trend in trying to get you to buy a brand of food instead of a competitor's. It's used a lot in children's food advertising. But just what is GI? And more importantly, how can we use the Glycemic Index to better choose healthier meals?

Scientifically speaking, the Glycemic Index is a representation of how much energy is released to the bloodstream (in the form of blood sugar) over 2 hours. It's then compared to the release for pure glucose (or sometimes white bread), and given a rank from 0-100. The higher the number, the more (or faster) energy is released from a food in 2 hours.

So now that we know that, we understand what it means when a food is low-GI'. But what does low-GI actually do for our diets? Studies have shown that a long term diet of low-GI foods can help weight control, while high-GI diets have an increase instance of heart disease and diabetes. But that's not the whole answer.

To really understand the Glycemic Index, it's a little more complicated than just low GI is good' and High GI is bad'. You see, we have to get scientific again. The GI of a food is rated on the same amount of carbohydrates, or energy. So it doesn't matter if you eat 2000 calories of low-GI food or high-GI food...you have still eaten 2000 calories and you need to burn that off or it will convert itself into body fat.

Here's the other thing: Sugar is absorbed in the small intestine. And since GI is only rated over the first two hours, anything that keeps your food in your stomach longer means it will take longer to absorb the sugar. And that means a lower GI. What keeps things in your stomach longer? Fat, protein, and fibre.

As an example, let's have a look at the humble potato. Potatoes have a high glycemic index; they're full of starch (complex carbohydrates or sugars) and are packed with calories. As a high energy food, you should be limiting them in your diet. A baked potato has a GI of, typically, over 70. Now let's take that potato and lather it with butter and sour cream. What happens? The extra fat and protein keeps it in our stomach longer and lowers the GI! But does that make it healthier? Of course not!

So now we know that lower doesn't always mean better when it comes to GI, what's the good news? Well, slower release of sugars means that it is easier to control your blood

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