The limitations of the glycaemic index
If you’re mindful of the amount of sugar you eat, you’ve probably encountered the term glycaemic index, or GI. Food manufacturers love advertising with low GI’s, seeing as this generally makes a product friendly to both diabetics and people who follow a sugar-free diet.
And don’t get me wrong. GI is very important. This is the index that tells you how much a given food product will affect your blood sugar. It’s measured from 0-100, where 100 represents pure glucose. The GI of a food will give you a good indication of how much roller-coaster action you can expect from your blood sugar after you’ve eaten it.
At least potentially. The thing about glycaemic index is that it really only tells us half the story. Cause generally, we don’t eat pure honey (except me, of course) or pure butter. And even when we eat pure products such as bananas, they still consist of more than just their sugar content.
Breaking down glycaemic load
Glycaemic load, then, tells you how much a food will affect your blood sugar, in relation to the amount of carbohydrates that food contains and you eat. Let’s take bananas as an example. Bananas have a glycaemic index of 55, which is pretty high (table sugar is at 65 GI). However, they only contain 23 grams of carbohydrates per 100 grams of banana. And that’s where the sugar comes from.
When you’re trying to determine the glycaemic load, then, you look at how many carbohydrates a food you eat is adding to your system. You multiply this by the glycaemic index (cause the glycaemic index only really represents the sugar, or the carbohydrates), and then divide it by 100.
Whereas the GI of bananas is 55, the glycaemic load of 100 grams of banana is at 12,65. This is considered a lower-end medium glycaemic load. But as you know, I like to stay in the lower end of any sugary scale, so this is still slightly higher than I generally prefer.
Honey, bananas and why my honey banana bread has a high GL
Bananas are only 23% carbohydrates, and thus the high glycaemic index of 55 only applies to 23% of them. Honey also has a high glycaemic index, at about 60 when it’s high in fructose, only 5 points behind table sugar. As opposed to bananas, though, honey consists of 82% carbohydrates, all of which are natural sugars. So that high GI in honey ends up being counted in much more of the product’s total weight. Think of it this way: Per spoon of honey, you’re ‘eating’ way more GI than you are per spoon of banana.
My counter-balance for high-GI ingredients in my baking is the wondrous product FiberFin, which is made from resistant starch. This has been proven to stabilise the blood sugar rise resulting from eating sugary food, and ensures a more stable increase and decrease.
Unfortunately, there aren’t any formulas for calculating the extent to which fibre reduces the GI or GL of a given food, at least not to my knowledge (if you know of one, please let me know!). So I can’t really take it into account in my nutritional calculations. And because I want to avoid any of my readers thinking something is less sugary than it really is, my honey banana bread is listed as one of the high-GL recipes on my blog.
Tips for reducing the glycaemic load
That being said, I personally didn’t react to my honey banana bread either way. And I usually do when I consume high amounts of sugar. Remember that both the FiberFin and bananas contain fibre. Here are some things you can do to reduce the honey banana bread’s glycaemic load, though:
- Substitute the wheat flour for wholegrain flour
- Cut 50% of the honey from the recipe
- Use fewer bananas in the recipe (3 should be enough)
- Add in slightly more FiberFin (or another source of fibre that will ensure a more stable blood sugar rise)
I hope that’s given you some clarity about the difference between glycaemic load and glycaemic index. Please don’t hesitate to send me an email at [email protected] if you have any questions.