FOCUS NUTRITION #1 WHAT IS THE GLYCAEMIC INDEX?

The glycemic index table for foods

The glycemic index is identified using a table listing each food, dividing them into three categories: low GI (<40), moderate GI (between 40 and 60), and high GI (>60).

Here is the glycaemic index table for foods...

Which low GI foods should you choose? 

Il est difficile de faire plus précis et détaillé que le tableau d’indice glycémique ci-dessus, mais globalement, voici une petite liste des aliments à indice glycémique bas (IG < 40) particulièrement adaptés aux sportifs.

• Tofu, vegetables (lentils, chickpeas, split peas), dark chocolate, quinoa, plain yogurt, almonds, hazelnuts, walnuts, cashews, pistachios, agave syrup, and basically all fruits and vegetables: kiwi, melon, grapes (black, they're full of "athlete's antioxyants) banana and red beans... 
• Benoît Nave completes this list with a few foods he recommends for sports: cooked brown rice, sweet potatoe, oat flakes, spelt flour, rye flour, multigrain wholemeal bread, wholemeal pasta, sourdough bread...

Jocelyn Guillot's top 3 low glycemic index foods for your sports nutrition

• Whole wheat bread
• Almonds
• Lenses 

“These are only raw foods that are readily available in stores and that we are used to eating. They are also foods that are high in protein, fiber, vitamins, and minerals. Nothing but good stuff!”

How can you control your glycemic index?​ 

Make sure your food is cooked properly

“The longer a food is cooked at a high temperature, the higher its GI will be!” says Jocelyn Guillot. He adds: “It's a simple tip, but cooking pasta al dente will tend to lower its glycemic index.” Similarly, as a nutrition expert, he advises you to “opt for steaming or baking as much as possible, especially for fruits and vegetables.”

Encourage combinations ​

The presence of other nutrients will lower a food's glycemic index. Benoît Nave explains: “If carbohydrates are accompanied by proteins and lipids, this will slow down their absorption and therefore lower the GI.” Jocelyn Guillot adds mischievously: “Contrary to what one might think, adding a knob of butter to mashed potatoes can be beneficial in that it will reduce its high glycemic index!” This ties in with the concept of matrix effect food ;) 

Connect the fibres

No, we're not talking about Wi-Fi networks, but rather connecting as much as possible with foods containing fiber! Fiber slows down digestion and therefore slows down the release of sugars into the bloodstream. As you now understand, this lowers the glycemic index. This explains the success of raw vegetables, raw fruits, legumes, and other “whole” starchy foods such as rice and pasta.

Roll on youth!

When it comes to fruit, the riper it is, the higher its GI will be. To give you an idea, a ripe banana has a GI of 60, compared to a GI of 45 for a green banana. So make sure your fruit is ripe... but not too ripe!

A dish that's best eaten cold!

For foods containing starch (potatoes, rice, corn, or wheat), there is one foolproof tip: eat them cold! When cooled, starch changes and becomes much more resistant to digestion, releasing the sugar contained in the food more slowly into the bloodstream. For example, a cooked, hot potato has a high GI of 88, which drops to a moderate GI of 58 when cooked in a salad.

Don't confuse sweetness with the glycaemic index

Here is one of the best tips from our two nutritionists: “The glycemic index of a food is not proportional to its sweetness, whether pronounced or not.” So be careful not to make this mistake: “Just because a product doesn't taste sweet doesn't mean it doesn't have a high GI!”

The difference between glycemic index and glycemic load

Or how to know what foods to eat and how much per day

Armed with this information, you are probably wondering how to “calculate your daily glycemic index.” The answer is simple: it's not possible! The glycemic index is a purely informative figure that defines the quality of a food. To incorporate the concept of quantity, we need to look at the glycemic load (GL). This allows us to determine what is good to eat, when, how, why, and above all, in what proportions. Are you already familiar with GI? That's great, because Benoît Nave and Jocelyn Guillot will introduce you to the concept of GL, “which is even more interesting when you want to optimize your performance and health.” Like the glycemic index, the glycemic load is classified into three categories:

• low GL : < 10
• moderate GL : between  11 to 19
• high GL : > 20

The glycemic load is therefore complementary to the glycemic index. It will help you determine the amount of sugar absorbed for a given quantity of a specific food. Benoît perfectly illustrates this concept with the example of watermelon: “It has a high glycemic index (75), but the amount of sugar contained in watermelon is so low (this fruit is actually composed of a lot of water and fiber) that its glycemic load is ultimately very low.”  

How to calculate your glycemic load?

To calculate its glycemic load, you need to revisit your math lessons and the “rule of three.” To find out the glycemic load of a food, you need to multiply its glycemic index by the amount of carbohydrates in a “normal” (i.e., reference) serving of that food, then divide by 100. Here is the formula (don't worry, if you also prefer sports to arithmetic, we have provided a glycemic load table a little further down in this article): 

Glycemic load = GI x amount of carbohydrates in one serving of food / 100

Why is it so important to differentiate between the glycemic index and glycemic load?

“We may tend to avoid foods with a high or moderate glycemic index, considering them unhealthy, when in fact, based on the amount we usually consume, their glycemic load is low,” explains Jocelyn Guillot. The example of potatoe puree illustrates this phenomenon very well. The GI of potatoes (90) is high. However, an average serving of about 150 g of mashed potatoes contains “only” 22.5 g of carbohydrates. The calculation is as follows: GI = 90 x 22.5 / 100 = 20.2. Its glycemic load is therefore moderate, while its glycemic index is very high.

“The glycemic load also helps us realize how certain foods that we don't necessarily suspect are actually little sugar bombs,” warns the young nutritionist from Chambéry. The example chosen this time is the classic French baguette. Its GI (70) is lower than that of potatoes, yet its glycemic load is twice as high. Why? Because it contains 56.6 g of carbohydrates per 100 g, which is the amount we normally consume. This gives the following calculation: GC = 70 x 56.6 / 100 = 39.6. Yes, bread, especially industrial bread, has an extremely high glycemic load.

The ideal glycemic load outside of sports

But in practical terms, what guidelines should you follow to stay healthy and perform well in sports? When should you eat foods with a high glycemic index? What should you eat, when, and why? 

First of all, you should know that the glycemic loads of the different foods eaten during the day add up to form a daily glycemic load. According to Benoît Nave, the ideal daily glycemic load for a sedentary adult or an adult who exercises on their day off is around 35 or 40.

To achieve this ideal glycemic load, our team has put together a menu idea that is as delicious as it is healthy:

• For breakfast: 2 soft-boiled eggs + 1 slice of ham + 1 handful of nuts + 1 piece of fruit. The glycemic load of your breakfast is then 5.
• For lunch: 1 serving of grated carrots + 1 plate of vegetables + 1 piece of meat or fish + 1 apple compote. The lunch CG is therefore 10.
• For your afternoon snack: 1 Baouw bar + 2 squares of chocolate. The glycemic load of your snack is 10.
• For dinner: 1 plate of raw vegetables + 1 soup + 1 serving of small oily fish such as sardines or mackerel + 1 fresh cheese. The glycemic load of your dinner thus achieves a respectable score of 10. 

Result: we obtain the ideal daily glycemic load of 35, recommended by our nutritionist for a day without exercise.

Glycemic load and exercise 

What should you eat before, during and after training?

Whether you wonder about specific triathlon nutrition, 10 km nutrition Or even the ideal diet for trail running, we reveal all the secrets of the relationship between your sporting activity and the concept of glycemic load. 

In order to optimize your athletic performance, your blood sugar level must be both high and as stable as possible throughout your workout. This will help you feel good and enjoy your exercise: when you have the energy you need to achieve your goal, without feeling sluggish or getting stomach pains. 

To do this, you need to pay attention to your diet before, during, and after exercise. “The first thing to do is to increase your daily glycemic load so that you have enough energy to successfully complete your trail run, road run, or bike ride,” emphasizes Benoît Nave. Jocelyn Guillot agrees: “You need to adapt your glycemic load to your sporting activity. You don't eat the same thing on a training day as you do on a rest day.”

Here are several tips to follow and concepts to keep in mind: 

• When you exercise, your daily glycemic load can reach 70 to 80, compared to 35 to 40 on a sedentary day.  
• Focus on meals with a high glycemic load around your workout. Specifically, eat carbohydrates for breakfast before your workout and lunch after your workout if you train in the morning. If you prefer to work out in the evening, eat carbohydrates at lunchtime and dinnertime. In addition, to replenish the reserves you are about to draw on or have just used up, choose foods with a low glycemic index as much as possible, as identified in the table above. 
• For endurance activities, from simple hiking to ultra-trail running, we strongly recommend that you choose sports nutrition products with a low glycemic index.
• High GI foods are preferable, however, “around exercise,” especially when it is going to be intense. In practical terms, it may be beneficial to consume foods with a high GI just before or during exercise when you know your heart rate will increase. Above 70% of VO2 max, i.e., when the exercise begins to be sustained, the body will prefer carbohydrates as a source of fuel, hence the importance of making them available quickly and in sufficient quantities.  

To promote recovery, Jocelyn Guillot also recommends “choosing foods with a medium or high glycemic index during the famous metabolic window, i.e., within an hour after finishing your workout.” Benoît Nave adds to this by suggesting “a good apple juice or grape juice as a post-workout drink.” 

Our nutrition expert even suggests the ideal menu for a 100% recovery meal to prepare for your next long run or tough workout: raw vegetables as a starter, mashed potatoes, small oily fish, plain yogurt, and a pan-fried banana...

Make way for the glycemic load chart for foods

This table of the glycemic load of foods helps you determine what to eat and when! You can also find out your daily glycemic load by referring to it regularly.

Here's a table showing the glycaemic load of foods:

Last but not least: the insulin index

The definition of the insulin index

The insulin index is the most recent concept, but certainly not the least interesting when it comes to achieving an optimal diet for health and fitness. Benoît Nave defines it as the “actual amount of insulin secreted into the blood after consuming a given food.” Unlike the glycemic index, which calculates the amount of sugar in the blood, the insulin index determines the amount of insulin, i.e., the presence of this hormone secreted by the pancreas to regulate blood sugar levels in response to an increase in blood sugar.  

The relevance of the insulin index

“Generally speaking, the glycemic index and insulin index overlap. A food with a low GI also has a low insulin index. But sometimes this isn't the case!” points out our nutritionist. “Plain yogurt, for example, has a low glycemic index in absolute terms (35) but an insulin index as high as an industrial chocolate bar (around 122)! This is because of the whey it contains,” he warns. This third index, in addition to the other two, allows you to take a very detailed approach to what's on your plate! 

The insulin index table