Low glycemic diet: What’s it all about?

Low glycemic diet… Most of us have heard about it but what is it all about? It sounds complicated but it’s not. And it makes a lot of sense.

Low glycemic diet

I’ve just finished Whole30 (take a look at my Whole30 results), but I’ve been fascinated with glycemic index (GI) for a while now. It seems to me that whenever there’s new research on diets it seems that glycemic index is in one way or another behind most of the modern diets that are considered effective. If you are not familiar with this concept, then here’s a little guide for you, an ABC of GI.

What is a glycemic index?

The glycemic index tells you how much a food that contains carbohydrates raises your blood glucose (=your blood sugar):

If the food you eat has a high GI it means that it raises your blood glucose a lot.
If the food has a low GI then it doesn’t affect your blood glucose that much.

If your glucose levels rise a lot it means that your insulin levels rise as well. Your body produces insulin to bring your blood glucose down. This is bad news for you because the insulin will do this by turning the sugar in your blood to fat. When this happens you will either gain weight – or at least will find it very difficult to lose any body fat.

That’s the theory behind low glycemic diet: If you want to lose weight (or are diabetic), you should concentrate on low GI foods.

Glycemic load

What’s important though is to understand the concept of a glycemic load.

White bread has a high GI value. However, if you have just one small bite of bread, it won’t affect your blood sugar that much.


Because the glycemic response of your body is dependent on the type and amount of the food you eat. That’s what glycemic load means.

Also, when you eat what matters is not the GI of a single ingredient, but the glycemic index of the carbohydrates of the entire meal. It might be OK to have a single ingredient that has a high GI if everything else on your plate is low GI.

Constant blood sugar level is the best

A lot of people think that in order to keep their blood sugar stable they need to eat several small meals a day. That’s not exactly true. If you pay attention to the glycemic index of the food that you eat you can very easily have just three meals a day without much consideration to your blood sugar levels at all.

The drop in blood sugar usually happens when you eat high GI food. You will first get a sugar spike and then crash down. After the initial burst of energy you will become hungry again and lose all the energy. And get more body fat.

If you have diabetes it is very important that you keep your blood sugar/glucose level constant.

What are high GI and low GI foods?

Only food that contains carbohydrates has a glycemic index value and the value can be anything between 0 – 100. Pure glucose has a GI value 100.

The food is considered low GI if the glycemic index of the carbohydrate is 55 or less, and low GI if the glycemic index is 70 or more.

Here’s a list of glycemic index values of some common foods:

list of glycemic index values

Source: Harvard Health Publications

If you want to know more, here’s a comprehensive table of GI values

New research on blood sugar response

There’s been a large study recently on blood sugar and how it affects people. The results are quite exciting:

Our bodies react very differently to identical foods.

There was an example where a person had an obvious rise in blood sugar when they ate a cookie but there was no difference in blood sugar when they had a banana.

Another person had a completely different response: That person could eat a cookie with very little difference to their blood sugar but an obvious sugar spike when they ate a banana.

The blood sugar levels varied also depending on whether the person had just exercised or slept!

More about this study

There’s a whole new world of research opportunities based on this information. I can just imagine how one day – very soon – we’ll all be taking lab tests to figure out what we can and can’t eat to lose weight. Who knows, I might be one of those people who’d lose weight by eating ice cream…

Do you pay attention to the glycemic index of the food that you eat?




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