The glycemic index of a food corresponds to its ability to raise blood sugar levels, or glycemia. Glucose is the reference carbohydrate with a GI equal to 100.
The low GI diet is actually based on the numerous researches conducted by scientists Prof. Jenkins and Dr. Wolever. It involves prioritizing foods with a low glycemic index on a daily basis.
Indeed, the lower the GI of a food, the less it impacts blood sugar levels. Conversely, foods with a high GI promote high blood sugar, insulin spikes, and fat storage.
The GI diet has proven effective in helping to lose weight healthily and to better understand how our body functions. Two studies have concluded a better weight and fat loss even among children and adolescents.
It is highly recommended for diabetics, but not only. Why controlling blood sugar with the low GI diet can help improve your weight and health?
As a dietitian, I share with you various studies on the subject and my nutritional advice to easily adopt it.
📚 Read also | The 10 best slimming programs on the market
1. We give an important place to plants
All carbohydrates cause an increase in blood sugar to a greater or lesser extent. And this glycemic spike occurs 30 minutes after consumption.
Uniquely, most vegetables have a GI below 15, which is very low. Their richness in fiber and nutritional composition are valuable assets.
Starting the meal with vegetables for better blood sugar is my first advice. Dedicate them at least half of your plate.
For example, you can choose a starter of grated carrots or crunchy vegetable sticks. Or have homemade soup before dinner, guaranteed satiating effect.
This meta-analysis confirms that weight loss is greater with the low GI diet compared to other diets and that satiety might be better when following this dietary approach.
| Food family | Low GI (0-55) | Moderate GI (55-69) | High GI (>70) |
| Fruits | Grapefruit (25) Apricot (34) Tomato juice (38) Apple, Pear (38) Prune (39) Unsweetened apple juice (44) Mango (51) Grape (53) | Papaya (56) Pineapple (59) Ripe banana (62) Orange (62) Raisins (64) Melon (65) | Watermelon (72) Dates (103) |
| Vegetables | Broccoli (10) Green beans, zucchini, leek, spinach, fennel, cabbage (15) Raw carrot (16) Cooked carrot (47) Squash (51) Boiled turnips (53) | Soup brick (60) Cooked beetroot (64) | Pumpkin puree (75) |
| Legumes and tubers | Soy, tofu (15) Split peas (22) Chickpeas (28) Lentils (32) Black beans (34) Green peas (41) White, red beans (42) Cooked sweet potato (46) Manioc (46) Corn (52) | Potato chips (56) | Boiled potatoes (78) French fries (82) Baked potato (95) |
2. Prefer whole versions over refined foods
Processed foods and high GI (>70 or moderate >55) often go hand in hand. Why? Because the various industrial processes often damage their fibers.
Let me give you an example: white rice has a moderate GI (58) whereas puffed rice cakes have a high GI (85), the same goes for quick-cooking bag rice (88).
It is preferable to choose the most unrefined form, that is, the whole version for a lower GI, or semi-whole depending on your tolerances (taste and digestion).
These are also of inferior quality carbohydrates generally used in industrial recipes: glucose-fructose syrup, white sugar… Combined with low fiber content, this explains their impact on our blood sugar levels.
Because fibers have a cushioning role, especially soluble fibers (vegetables, legumes, apple, pear…). They slow down gastric emptying and thus the absorption of glucose by the body.
However, there are some surprising exceptions in the GI classification table. This is the case with Nutella or Twix which find themselves in the low GI column for example!
Results should still be nuanced and can be explained by their high fat content. They slow down the arrival of sugar in the blood. However, this does not make them essential calories for the body given their composition: sugar and palm oil are the first two ingredients of the famous spread.
| Food family | Low GI (0-55) | Moderate GI (55-69) | High GI (>70) |
| Cereal products & grains | Barley, pearled barley (28) Rye (40) Al dente pasta (45) Whole grain bread, black bread (49) Brown, red rice (50) Ebly wheat (50) Oat flour, flakes (52) Quinoa (53) | Basmati rice (58) Pizza (60) Gnocchi (60) Soft-cooked pasta (62) White rice (64) Couscous (65) Whole wheat bread (65) Rusks (68) | White bread (70) Pretzel (83) Puffed rice cakes (85) Quick-cooking bagged rice (88) French baguette (95) |
| Biscuits & snacks | Nutella (33) All-Bran (34) Pepito (40) Twix, Snickers (43) Petit Beurre de Lu (51) | Popcorn (55) Muesli (57) Plain crepe (66) Tuc de Lu (67) | Chocolate bar (70) Granola bar (72) Baguette + spread (72) Donuts (76) Corn Flakes (77) Candies (>78) Energy drinks (90-95) |
🎧 Listen to our podcast | Who is afraid of ultra-processed foods?
3. Don’t forget good carbohydrates (but in reasonable amounts)
If quality matters, the amount of carbohydrates does too.
Two other concepts have emerged: glycemic load (GL) and insulin index (II). Both complement the glycemic index.
GL and II provide more information regarding the portions of carbohydrate foods consumed and their impact on blood sugar. Each results from a calculation:
- GL: (glycemic index x quantity in grams) / 100. Below 10, the glycemic load is considered low, and it is considered high above 20.
- II: insulin rate for 240 kcal of a food. Bread is the reference with an insulin index of 100.
Of course, consistencies are observable with the GI table. However, consuming too much of a low GI food can cause the same disorders: too much sugar in the blood that the cells do not need and which the body will store.
The recommended carbohydrate intake per day is 40 to 55% of the total daily caloric intake. Therefore, choose your ingredients well, in a reasonable quantity.
| Food family | Low GI (0-55) | Moderate GI (55-69) | High GI (>70) |
| Sugars & sweeteners | Fructose, Agave (15) Coconut sugar (35) Strawberry jam (46) Brown sugar, Maple syrup (54) | Reduced-sugar jam (55) Honey (58) White sugar (65) | Corn syrup (85) Glucose (100) |
| Beverages | Kombucha (26) | Coca-Cola (58) Beer (66) | Grenadine syrup (70) |
🎧 Listen to our podcast | Sugar or life?
4. To lose weight without yo-yo, combine proteins and low GI
Two studies conducted in 2008 compared the consumption of low glycemic index foods with the Mediterranean diet for one and the low carbohydrate diet for the other.
Better slimming results and a greater reduction in fat mass with the GI diet were observed. These examples among others confirm the interest of these dietary choices.
However, another essential nutrient seems to make the difference: proteins. Essential for nourishing muscle mass, this study proved that the low GI diet enriched with proteins is the one that allows sustainable weight loss, better stabilization.
This gave rise to the new low GI diet which in its recommendations adjusted the daily protein quantity: 20 to 25% of total energy intake.
Integrate enough animal proteins in main meals: lean meats, fish and shellfish, oily fish twice a week, and eggs.
Then, incorporate low GI plant proteins into your daily routine: lentils, chickpeas, red beans, peas… They are ideal for varying from potatoes or other higher GI carbohydrates, a double advantage!
5. Choose good fats with a low glycemic index
Lipids are essential for the proper functioning of the body. It is therefore not a question of eliminating them.
A study has compared the GI diet with a low-fat diet. Conducted among overweight adults in 2007, the interest of the low GI diet in weight loss was considerably higher.
On average, 25% of the total food intake in the GI diet should be represented by lipids. Favor plant-based fats in your dishes: olive oil, flax, rapeseed…
Good news, some low GI foods are also sources of good fats. This is the case with nuts: walnuts, peanuts, hazelnuts, almonds…
I advise you to regularly include them as low GI snacks: a handful of nuts for breakfast and at 4 PM, an apple in pieces with peanut butter
Choose avocado or tofu to vary from cheese rich in saturated fats, for example. Fatty foods are not forbidden, just choose wiser for the sake of your cardiovascular system.
| Food family | Low GI (0-55) | Moderate GI (55-69) |
| Nuts | Pecan nuts (10) Salted roasted peanuts (14) Walnuts, pistachios, almonds (15) Cashew nuts (22) | |
| Milks, yogurts & derivatives | Greek yogurt (11) Whole or semi-skimmed milk (27-30) Skimmed fruit yogurt (28) Almond, oat milk (30) Sugared yogurt (33) Soy milk (36) | Ice cream (61) Sweetened condensed milk (61) Chocolate milk (64) |
6. Follow guidelines for low GI meals
To avoid blood sugar spikes, the preparation of your meals is important.
Here are my tips for lowering the glycemic index of your meals:
- opt for complete meals with proteins, vegetables, and fats rather than a single carbohydrate
- prefer short cooking times and reheat your dishes in the microwave
- limit the amount of water for cooking your vegetables, keeping them whole or in large pieces
- eat your moderately or highly GI foods preferably cold (potatoes, rice…)
- add a note of acidity like vinegar or lemon
When your body receives too much sugar, it stores this excess as fat. This is followed by a drop in insulin and then blood sugar, often leading to a desire to eat again. Your body becomes exhausted.
These tips help you promote a stable blood sugar for more energy. A tasty fruit with plain yogurt and pistachios will lift your spirits, rather than a piece of baguette.
7. A diet without prohibitions with multiple benefits
The new low GI diet suggests three phases to gradually lose weight. In the first few days, integrate only very low GIs <20. Then low GIs <55 until you reach your goal.
Then, to stabilize: low to moderate GI foods can be consumed for your new routine.
Unlike other dietary programs, the low GI diet does not forbid carbohydrates but constitutes a real strategy.
The low GI diet can be suitable for the whole family, which I consider a great advantage. For pregnant women and diabetics, nutritional support is necessary at the beginning to adjust meals (timing, quantity…).
Beyond weight loss, the other benefits of the low GI diet are numerous: improved cognitive functions, fight against inflammation, against insomnia…
You know everything now! You have the nutritional guidelines to better choose your foods, properly prepare your upcoming shopping, improve your habits and mood.
📚 Read also | The 9 Best Meal Boxes and Plans Online
Sources and scientific studies
Cara B Ebbeling, Michael M Leidig, Kelly B Sinclair, Jan P Hangen, David S Ludwig, 2003. A reduced-glycemic load diet in the treatment of adolescent obesity.
Iris Shai, Dan Schwarzfuchs, Yaakov Henkin, Danit R Shahar, Shula Witkow, Ilana Greenberg, 2008. Dietary Intervention Randomized Controlled Trial (DIRECT) Group – Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet.
Jennie Brand-Miller, Joanna McMillan-Price, Katherine Steinbeck, Ian Caterson, 2008. Carbohydrates the good, the bad and the whole grain.
E E J G Aller, T M Larsen, H Claus, A K Lindroos, A Kafatos, A Pfeiffer, J A Martinez, T Handjieva-Darlenska, M Kunesova, S Stender, W H M Saris, A Astrup, M A van Baak, 2014. Weight loss maintenance in overweight subjects on ad libitum diets with high or low protein content and glycemic index: the DIOGENES trial 12-month results.
Cara B. Ebbeling, Michael M. Leidig, Henry A. Feldman, et al, 2007. Effects of a Low–Glycemic Load vs Low-Fat Diet in Obese Young Adults, A Randomized Trial.
Yeonsoo Kim, Jie Chen, Michael D Wirth, Nitin Shivappa, James R Hebert, 2018. Lower Dietary Inflammatory Index Scores Are Associated with Lower Glycemic Index Scores among College Students.
James E Gangwisch, Lauren Hale, Marie-Pierre St-Onge, Lydia Choi, Erin S LeBlanc, Dolores Malaspina, Mark G Opler, Aladdin H Shadyab, James M Shikany, Linda Snetselaar, Oleg Zaslavsky, Dorothy Lane, 2020. High glycemic index and glycemic load diets as risk factors for insomnia : analyses from the Women’s Health Initiative.
