Glycemic index: sense or nonsense?
The glycemic index (or short GI) is an index of foods based on the speed increase of your blood sugar levels. More often we see references to this GI-index. But what is it exactly and how do we need to use this index?
In the early 80's Professor Dr. Jenkins described the glycemic index. As a starting point they mostly use 50 grams pure glucose. This is the reference point (100) to which other products are compared. 2 hours after eating 50 grams of a certain food the blood sugar level is measured again to see how much it has increased. This is of course a simple way of explaining how the real index was made. So foods with a high GI make your blood sugar levels increase very quickly. The index has 3 main sections:
– Low GI : less than 55
– Medium GI : between 55 and 70
– High GI : more than 70
Here some examples of popular food :
| Food | Glycemic index |
|---|---|
| white bread, bagel | 70-80 |
| whole wheat bread | 74 |
| corn flakes | 85 |
| white rice | 73 |
| brown rice | 60 |
| potatoes boiled | 60 |
| potatoes baked, deep fry | 85 |
| oatmeal no instant | 40 |
| oatmeal instant | 79 |
| apple | 38 |
| pear | 35 |
| grapes | 46 |
| banana | 51 |
| mango | 51 |
| tomatoes | 15 |
| carrots | 48 |
| broccoli | 10 |
| milk skim-fat | 37-39 |
| yoghurt skim, natural | 35 |
| chocolate +72% | 22 |
| chocolate milk | 49 |
| popcorn | 65 |
| Potato crisps | 56 |
Other considerations according to the index:
– ripe fruit has a higher index.
– preparation method : for example mashed potatoes have a higher index value then boiled potatoes Cooking and baking break down the starch as a result the intake is much quicker.
– foods who have a lot of fibers result in a slower increase of the blood sugar levels and therefor they have a lower index value.
– the speed op sugar intake slows down by eating fibers, fat or proteins.ten of vetten
So far so good … this seems easy … We just try to avoid the products with a high index value. But unfortunately it's not that simple. As you could read it also depends on how you prepare your food. Do I peel the fruit or not - what do I eat together - ... So the scientists came up with a new term: the glycemic load (GL).
The glycemic index tells us how quickly the blood sugar level will rise for 1 type of food. The glycemic load looks also at the portion of that product. This way we get a better view on what's happening with the blood sugar level in our body.
A high GL value will result in a quick peak in the sugar level, followed by a huge decline. So we will notice we're hungry again after a short time, and we will start eating again. This way we eat more that we need and we will gain weight.
These are the values used for the glycemic load:
– Low GL : less than 10
– Medium GL : between 10 and 20
– High GL : more than 20
So this is how the list looks like (1 portion):
| Food | Glycemic load |
|---|---|
| white bread, bagel (1 slice) | 17 |
| whole wheat bread (1 slice) | 14 |
| corn flakes (30 gram) | 23 |
| white rice boiled (150 gram) | 43 |
| brown rice boiled (150 gram) | 16 |
| potatoes boiled (150 gram) | 14 |
| potatoes baked, deep fry (150 gram) | 33 |
| oatmeal no instant (250 gram) | 13 |
| oatmeal instant (250 gram) | 24 |
| apple (30 gram) | 6 |
| pear (30 gram) | 4 |
| grapes (120 gram) | 9 |
| banana (120 gram) | 11 |
| mango (120 gram) | 8 |
| tomatoes (100 gram) | 1 |
| carrots (80 gram) | 2 |
| broccoli (100 gram) | 1 |
| milk skim-fat (250 ml) | 4 |
| yoghurt skim, natural (175 ml) | 4 |
| chocolate +72% (50 gram) | 6 |
| chocolate milk (50 gram) | 12 |
| popcorn homemade (30 gram) | 9 |
| Potato crisps (35 gram) | 8 |
Wow ... This is a lot of information ... Still remains the main question: Glycemic index: sense or nonsense?
Personally, just looking at the glycemic index is a bit to narrow. It's better to look at the glycemic load, and of course using some common sense. I will illustrate this with an example: 50 grams of dark chocolate (min 70%) has a GI of 22 and a GL of 6. At first instance it looks good. An apple has a GI of 38 and a GL of 6. But when you eat an apple, you also have a lot of vitamins, fibers and anti oxydants. So although the values of an apple are higher, this is a better option.
Every now and then I love a waffle. But when I eat a waffle, I notice a high peak in my blood sugar. If I eat it with fresh whipped cream (fat) and some strawberries (fibers) the raise in the blood sugar goes slower. So my advice is: if you really want to have something with a high index value, try to combine it with some fat (unsaturated fat) and fibers.
On internet you can find tons of information and lists with the GI or GL values. But don't get overwhelmed by it. In the beginning, you will need to have a look at the list quite often, but soon it will be a habit. I used it as a guideline in case of doubt. The more time you spend on healthy living and cooking, the less you will need this list.
Hopefully the difference between the GI and GL is now a bit clear to you. And it's up to you to answer the final question: "Glycemic index: sense or nonsense?"
For me it all made sense and helped me in a good and healthy diet. I saw the effect on my body when I follow the guidelines.
Stay safe and healthy!