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Oh Sugar! Glycemic index and glycemic load

We all know that refined sugar is bad for us, but why? Because it’s not just empty calories, it actually steals nutrition from your tissues. Your body needs those nutrients to process the calories in sugar. But that leaves the body feeling undernourished and therefore, you got it! Hungry!! If we then eat a meal that is high in refined sugars, the cycle repeats, and can repeat again and again! This can be a major contributor to the “overfed and undernourished” syndrome we talk about in the The Dirt on Ultra Processed Foods. There’s really nothing good about it. 


Unrefined sugars, such as honey and maple syrup, contain some minerals and vitamins your body needs to process the sugar content, so they don’t leave your tissues depleted in the same way. And they have flavour, so you notice that sweetness when you are eating them. Molasses, which has very strong flavour, was historically used to sweeten food, and also to help raise peoples’ levels of iron, because it is so nutrient-dense. 


But too much sugar of any kind causes problems. High blood sugar levels, in the long run, cause insulin resistance, the main precursor to Type 2 Diabetes. Those excess sugar molecules can attach to proteins in our bodies in a process called glycation, making the proteins “sticky” and preventing them from working optimally. One example of this is a blood marker for high long-term blood sugar, called hemoglobin A1c. This measures how much sugar is stuck on the hemoglobin in our red blood cells, and if this is happening in the red blood cells, it’s happening throughout the body!


Recognising sugars in foods. If you are looking at a label, note that if a product contains more than one sugar, they will be listed as separate ingredients. We have seen products with 5 different sugars listed! Glucose, fructose, sucrose, mannose, dextrose, lactose, maltose; in fact anything that ends in “..ose” is a sugar. In addition there may be syrups listed, like high fructose corn syrup, which are very concentrated sugars.


In many other countries you will see a nutritional breakdown which includes total sugars and carbohydrates. 


But what about fresh foods? 


The Glycemic Index (GI) is a measure of how quickly a food increases your blood sugar. In order to assess the effects of each individual food, it is measured when that one food is eaten alone. Therefore the GI doesn’t reflect how we eat our meals, as we eat several foods together, but it does give us a basis for comparison between different foods. 


We know that eating a low GI food along with a high GI food will slow the rate that sugars get into our bloodstream, tempering the glycemic effects of the high GI food. For example, low GI nut butter, containing protein and fat, moderates the high GI of toast or a rice cake.


Chicken, fish, meat and eggs have a glycemic index of zero (0), because they have so little effect on blood sugar levels. Pure glucose defines the other end of the GI scale, at 100. All other foods lie somewhere in between. Up to 55 is considered low GI, 56-69 is classified as medium GI, and over 70 is high GI


GI is affected by factors such as:

  • How ripe the fruit or vegetable is: for example, a ripe banana has a higher GI than a green one. 

  • Whether a food is cooked: the cooking starts the breakdown of starches, so the body has less work to do to turn those starches into sugar. Cooked carbohydrate foods tend to have a higher GI; for example apple sauce has a higher GI than a raw apple.

  • More highly processed foods tend to have a higher GI. For example, a bowl of Cheerios or instant oat flakes both have a higher GI than steel cut oats.

  • Foods with high protein, fat or fibre content tend to be lower GI foods. And you want those to be healthy proteins and fats, of course!


But that’s not the whole story, because it doesn’t take into account how much of that food is eaten in a meal. That’s where the glycemic load (GL) comes in. It is a measure of the total amount of sugar consumed in a meal. 


So the GL helps calculate how much a particular meal will elevate a person’s blood sugar, and will contribute to their total carbohydrate intake for the day. 


The good news:  if you love some high glycemic index foods, and you are generally healthy, you can enjoy them in moderation. Just make sure you balance them with healthy proteins and fats. And if you are looking to have a high-nutrient eating plan to assist weight loss or blood sugar control, you can load up with low GI foods and low GL meals. They are fabulously good for you, and leave your cells satisfied, while not indulging a sweet tooth! 

You can find lists of low and high GI and GL foods on this link: 

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