What is the Glycemic Index and Why Does it Matter?
Improving our blood sugar levels can be the key to a healthy lifestyle. We all wish to live a healthy, energetic, and stress-free life, and to reach this goal, we need to be in control of what food provides the most energy for us, and how can we put this energy to good use.
All types of food provide energy, but glucose is the nutrient that is used as the main source of energy. However, to achieve a healthy weight-loss and normal blood sugar levels, it is essential to focus on the glycemic index of each food.
What is the glycemic index?
When we eat, we fuel the body with energy from the essential nutrients: glucose, fats, and proteins. Out of these three macronutrients, glucose is the most important when it comes to energy levels, as it is used as the main source of energy for the cells. During the digestion process, food is broken into small molecules that are absorbed into the bloodstream and sent straight to the cells.
Glucose is the molecule that results from the digestion of carbs, and with the help of a hormone called insulin, it is transported into the cells where it provides energy. Depending on the type of carbs that we eat, there is a possibility that there is not enough insulin to transport all glucose molecules, so glucose will end up staying in the bloodstream, causing high blood sugar levels.
When it comes to deciding which types of carbs we should eat, the glycemic index (GI) comes in great help. The GI is a value that was given to food, depending on the immediate impact of carbs on blood glucose levels. Food that causes a slow release of glucose into the blood has a low GI, whereas food that causes a rapid release has a high GI, causing high blood sugar levels. The GI is commonly used as a guide to food selection for people with diabetes, but it also became popular among people who want to achieve a healthy weight-loss.
How is the GI measured?
The scale of the GI can range between 0 to 100. The best food options for a healthy weight-loss and improved blood sugar levels are the ones with the GI under 55. To measure the GI, clinical research facilities started by feeding 10 people with a type of food that has around 50 grams of carbs, and during the following two hours, they monitored the rise of their blood glucose levels. The following day, they fed the same people with 50 grams of pure glucose, and during the following two hours, they measured the rise in their blood glucose levels again. The GI value for that specific food, is found by dividing the results from eating the carbohydrate food, by the results from the pure glucose test, times 100.
The final GI value of the food is the average for all 10 people that were tested. Thankfully, we don’t have to go through all the trouble of calculating the GI. Scientists did these tests for all types of food, and there are many charts available that express the GI value for each food in particular. The GI is usually calculated as an average value, and it is not based on an individual unique response to food, so its effect on blood glucose levels depends on every person’s metabolism.
What is the glycemic response?
When we eat carbs, we trigger a glucose response which refers to the changes in the blood glucose concentration. This response can be calculated with the help of the glycemic index and the glycemic load, and it is used to see how certain carbs are absorbed into the bloodstream and what effect it has on human health.
Why is the glycemic response important? As the world becomes more used to the consumption of sugar, the risks of obesity and type 2 diabetes are rising. Sugar is used for its sweet properties but it is also used as a preservative. It can be added to canned foods, bread and even water, but unfortunately, it can cause sugar spikes and if it is used in high amounts, it can even lead to diabetes. The glycemic response can show us how our body reacts to certain foods, so that we know what to avoid in the future. The glycemic response can be checked by monitoring our blood sugar levels with the help of a CGM (continuous glucose monitor) device. When a certain carbohydrate food causes a high sugar response, the CGM monitor will alert us.
To find out the value of the glycemic index of each food, 50 grams of a specific food has to be eaten at once. As people are not able to consume exactly 50 grams of a specific food at once, with the glycemic load we can find out how much will raise the blood glucose levels one portion size of carbohydrate food. With the help of the glycemic load, we can predict glycemic responses from typical serving sizes.
The glycemic load is another way to analyze carbs, but it takes into account both, portion sizes and the GI. The glycemic load is a more realistic way of picturing a food’s effect on blood glucose levels. It is calculated by multiplying the grams of carbs in the serving size, by the glycemic index of the food, and then dividing it by 100. For example, if you want to find out the glycemic load of a portion size of watermelon, you can find the GI, which is 76, and then multiply it with the number of digestible carbs that it contains. A serving of 100 grams of watermelon contains 7 grams of carbs, so this means that the glycemic load of a portion of watermelon is 5. Foods are categorized from 0 to 20 and above, with 0 to 10 representing a low GL,10 to 20 representing a medium GL, and 20 and above being the high GL. Low GL means that the food portion will not cause a spike in the blood sugar levels, so it is recommended to follow a diet with low GL and GI, to keep the blood sugar on track.
What affects the glycemic index?
Now that we know what the GI is and how it can influence our health, let’s see what are the factors that influence the rise of the GI in food.
Fruit and vegetable ripeness
One of the main influences of the value of the GI is the ripeness of fruits and vegetables. We all know that ripe fruits taste sweeter than unripe ones, and this happens because unripe fruits have high amounts of starch and very low sugar content. As the fruit ripens, starch decreases while sugar levels increase, making the fruit tastier. This can influence the glycemic index, shifting it from a lower value to a high value, causing blood sugar spikes.
Food processing can also be a factor that influences the GI. By grinding, mashing, or cooking the food, we make the food easier to digest, by breaking it into small pieces. If carbs are easily digested, glucose can be absorbed quicker in the bloodstream, which can potentially cause a rise in the sugar levels.
Maybe you heard that apple cider vinegar can lower sugar levels, and this can happen because the fermentation process releases organic acids. These acids slow down the digestion of carbs, by lowering the GI value of the fermented food.
Fiber contributes to the GI of food, as it thickens the food, making it harder to digest. Soluble fiber can be found in oats, peas, and beans, having a great role in reducing cholesterol levels and stabilizing blood glucose. The thickening of the food bolus plays a big role in lowering the GI values.
GI and diabetes
There are two main types of carbs, complex and simple. Natural sugars that come from complex carbs have a low GI and they can be found in starchy vegetables and fiber. They take time to break down in the digestive system, which leads to a slow release of sugar. The consumption of processed sugars that come from simple carbs, can cause sugar spikes, as they are easily broken into digestible pieces. These can be found in soda, cakes, cookies, chocolate, sugar, and many other similar processed foods. A low GI diet can have a positive effect on blood sugar regulation and it also promotes weight-loss and the prevention of diseases like type-2 diabetes.
Diabetes is a common disease nowadays, caused by high levels of sugar in our bloodstream. When glucose molecules reach the bloodstream, insulin is secreted by the pancreas. Insulin is a hormone that helps with the transportation of glucose from the blood into the cells. People with diabetes don’t have enough insulin or the insulin that they have is not used as it should be, and glucose ends up staying in the blood for a long time.
Monitoring blood glucose levels is essential for people with diabetes, and using the GI as a tool before consuming food, can be a great way to prevent blood sugar spikes.
How to use the glycemic index
To make it easier for people to follow a low GI diet, scientists tested all foods and calculated the GI for each type of food. With the results, they created different food charts that are available at the doctor’s office, at the nutritionist’s office, and even online. These charts are meant to guide people in making the right decision when buying, ordering, or consuming food. The charts can be used not only by people who suffer from diabetes, but also by people who follow the keto diet or a low-carb diet. The charts include food items that contain carbs, but also the different ranges of the GI, from 0 to 100. Low GI foods are the ones that are 55 or less, medium GI varies from 56 to 69, and high GI foods are 70 or more.
There are also charts regarding the glycemic load, which give a wider perspective to people, regarding food portions and their effect on blood glucose levels. The range is between 1 and 20. Some people prefer the GL of the food instead of focusing on the glycemic index, but both values are a great help when it comes to monitoring diabetes or achieving a safe and healthy weight-loss.
What is a low glycemic diet?
As the name suggests, a low glycemic diet focuses on the glycemic index. Foods that have a low GI contain high amounts of starch and fiber, making it hard for the digestive system to process them in a fast way. If the food takes longer to digest, it results in smaller quantities of sugar released into the bloodstream, preventing the body from sugar spikes.
So what should you eat on a low glycemic diet? Similar to the keto diet, a low glycemic diet focuses on reducing carb intake, to start burning fat and reach the weight-loss goal. If the glycemic index is low, the blood sugar levels will stay low, and the body will start using fats as a source of energy. The burning of fats leads to a safe and precise weight-loss, making the low glycemic diet and the low-carb diet to be very appreciated lifestyle options.
Glycemic index foods and their ratings
If you want to start a low glycemic diet to improve your health, glycemic index charts come in great health. If you stick to consuming foods with a GI of under 55, you will definitely achieve your weight goals, and improve your blood glucose levels. Here are a few examples of GI foods and their ratings:
High glycemic foods - these foods should be avoided if you choose to follow a low GI diet
- White bagels: the GI is over 100, due to the white bread that has a strong blood sugar response
- Watermelon: the GI is 72, as the sugars are metabolized quickly
- Fried corn shells: 97
- Oatmeal: 87
- Baked potatoes: 85
- Muesli: 80
- Whole Wheat Bread: 71
Moderate glycemic foods - these foods can be consumed but on a limit
- Brown rice: the GI is 57, it contains lots of starches that slow down digestion and the release of glucose
- Ice cream: with the GI of 61, it is considered an accepted food option if it is consumed with limits;
- Pineapple: 66
- Couscous: 65
- White rice: 64
- Sweet potatoes: 61
- Black-Eyed peas: 59
- Mango: 56
- Other moderate GI foods: potatoes, beetroot, pumpkin, etc.
Low Glycemic Foods - These can be safely consumed when following a low glycemic diet
- Plain Yogurt: the GI is 14, which makes it the best food option when it comes to a low GI diet
- Grapefruit: the GI is 25, as the sweet and sour taste has a great effect on blood glucose levels
- Sweet corn: 54
- Grape: 46
- Cooked carrots: 39
- Chickpeas: 33
- Peanuts: 21
- Other low GI foods: non-starchy vegetables like asparagus, broccoli, cucumber, green leafy vegetables etc.
Meal ideas with low GI
There are a few basic nutritional recommendations when starting a low GI diet. The first one would be to try to eat at least 4 times a day, to avoid snacking throughout the day. Each meal should contain whole foods like vegetables, proteins, starches, and healthy fats. Combining proteins and starch, will result in slow digestion, which means longer satiation and slower glucose release. For example, if you combine turkey meat with potatoes, it will be harder to extract the glucose from the food bolus, so the sugar will be slowly released into the bloodstream. Another ideal recommendation is to combine eating healthy with regularly exercising, to promote a faster weight-loss and a healthy lifestyle.
Some of the easiest meal ideas that are ideal for people that want to start a low GI diet can include:
- Proteins: brown rice and chicken, turkey with vegetables, venison and shallots, prawn and tomato stew, chicken stew, chicken and mushrooms, salmon and broccoli, scrambled eggs with spinach and salmon;
- Fats: Greek yogurt and berries, oatmeal and flaxseeds, apple with almond butter, pasta with broccoli and almonds, crab-stuffed avocado;
- Fiber: sweet potato with black bean curry, lentils curry, mushroom risotto.
Our snacks that won’t hinder health
Other snacks that are safe to include in your low GI diet can be found on our website, alongside other useful information regarding the keto diet and its’ benefits. Here are the best snack options that have a low GI and won’t hinder your blood glucose levels:
Keeping the blood sugar on a low level is important for both, prevention and treatment. A low glycemic index of a food can secure a healthy weight-loss, but also healthy management of blood glucose levels. People with diabetes can prevent sugar spikes with the help of a low GI diet. Our keto snacks come in great help and if you are interested in more information regarding low-carb products, low GI diets, or keto diet, our blog offers a variety of interesting articles on different health related topics.
This information is not intended to prevent, diagnose, prescribe, or treat any illness or condition, nor does it take the place of sound medical advice. You should always seek out your own medical care and determine the best diet and course of treatment for your unique health needs.
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- David S. Ludwig, The glycemic index- Physiological Mechanisms Relating to Obesity, Diabetes, and Cardiovascular Disease;
- Sonia Vega-Lopez, Bernard J. Venn, Joanne L. Slavin, Relevance of the glycemic index and glycemic load for body weight, diabetes and cardiovascular disease;
- David JA Jenkins, Cyril WC Kendall, Livia SA Augustin, Silvia Franceschi, Maryam Hamidi, Augustine Marchie, Alexandra L. Jenkins, Mette Axelsen, Glycemic index: overview of implications in health and disease;
- The glycemic index measures how much specific foods increase blood sugar levels.
- Glycemic load is a measure that accounts for the amount of carbs in a portion of food together with how rapidly it raises blood sugar levels.
- Low glycemic foods are foods that have a GI of 55 or less.
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