The glycemic index diet is a diet that aims to consume foods that result in less of a spike in blood sugar levels, allowing you to feel fuller and more energized for longer.
What Is a Glycemic Index Diet?
The glycemic index diet is a relatively new age, science-backed diet that follows the footsteps of fat- and sugar-free diets of the 70s. From around the mid-1970s, there was the realization that ingesting the same amount of carbohydrates from different foods could result in significantly different overall blood glucose curves.
The glycemic index measures the carbohydrate concentration of different foods and their impact on blood glucose levels.
Foods are ranked on a scale of one to 100, and pure glucose is used as a reference point with a GI of 100. Low-GI foods are classified as being digested and absorbed slowly, with a GI score of 55 or less. These include grainy bread, fruit, and oats.
By contrast, high-GI foods are classified as being rapidly digested and absorbed, with a score of 70 or higher — like white bread, potatoes, and processed foods.
This indicates that low-GI foods release glucose into the blood at a slower, more sustained rate, resulting in less spike in blood sugar levels following a meal.
There is considerable variation among these low-GI foods, given their score can vary from zero to 55. You want to predominantly eat low-GI foods on the low glycemic index diet instead of foods with higher glycemic loads, like white bread.
A variety of factors impact the glycemic index of foods. They include how the food is processed and prepared, its fiber, sugar, and starch content, macronutrients, and levels of antinutrients. Antinutrients are plant compounds that interfere with the body’s ability to absorb nutrients. Foods that do not contain carbs are not on glycemic index lists.
How Glycemic Index Diet Works
The general philosophy of this diet is that it regulates the response of your blood glucose levels following a meal. Usually, your blood glucose levels should sit around 4 – 8 mmol/L, and they are lowest before a meal and spike directly after a meal.
Because the foods on this diet are processed more slowly, they prompt a more gradual rise in blood glucose — allowing you to feel fuller for longer, and preventing large swings in your blood glucose levels.
Exercise is not a necessary component of the glycemic index diet. However, this diet can influence your normal exercise regimen.
Some research has identified that low GI foods are more beneficial than high GI foods for endurance-based exercise. This is because low glycemic foods result in a greater rate of fat oxidation, resulting in delayed use of muscle glycogen stores.
Endurance training increases the body’s muscle glycogen stores while simultaneously lowering the body’s reliance on using these stores.
Consequently, consuming low GI foods alongside an endurance training exercise regime could boost your performance. Current research has not elucidated the impact of a glycemic diet on resistance training.
Breakfast could vary from banana oatmeal to a berry smoothie, eggs (however you like them!), or low-fat yogurt with chia seeds.
You can expect various options to cater to your tastes for lunch and dinner. Meals involving lentils, lean meats, eggs, wholegrain bread and pasta, beans, and vegetables are encouraged.
And remember: low GI does not mean low on flavor!
Meals on this diet can still be packed full of delicious herbs and spices. Low GI diets leave lots of room for snacks, too — plenty of nuts, hummus, yogurts, and popcorn are some great options to get you started.
Rest assured, this diet will get you results without breaking the bank. A study followed pregnant women on this diet, finding that they had a similar intake at the same cost or cheaper when compared to their meals before starting the GI diet.
Sample Diet Plan
Breakfast: Scrambled eggs on whole grain bread
Snack: Low-fat yogurt
Lunch: Chicken and mushroom quesadilla on a whole wheat wrap
Snack: Dark chocolate and almonds
Dinner: Grilled salmon with sweet potato fries
Health Benefits and Drawbacks
- Improved energy and mood
- Lowered risk of cardiovascular disease
- Reduced insulinemia
- Lowered total cholesterol and LDL (“bad”) cholesterol
- Control of body weight, body fat, and waist circumference
- Management of type 2 diabetes
The GI rating is not that simple: For example, a fruit’s ripeness can impact its GI, or cooking certain foods can raise their GI significantly.
We’re all different: Glycemic responses vary from individual to individual and can change at other times of the day.
Not all low GI foods are healthy: Sometimes, this scale can be misleading, so you may need to consider other factors. For example, potato chips, soft drinks, and ice cream are all relatively low GI but offer little nutritional gain on a weight loss diet.
Is This Diet Another Popular/Fad Diet?
What sets this diet apart is that it’s not a “quick fix” diet causing rapid weight changes that aren’t sustainable. It’s relatively easy to make the changes, allowing you to stay on it long term and maintain a varied, delicious diet to always be excited about your next meal!
The Bottom Line: Is Glycemic Index Diet a Healthy Way to Lose Weight?
Overall, the low glycemic index diet is a great option for healthy weight loss, and it allows you to learn healthy habits and keep up your energy levels.
It is also beneficial for reducing the risk of developing cardiovascular disease and type 2 diabetes (T2D) and aiding blood glucose control for individuals already diagnosed with T2D.
Finally, it’s a fantastic option if you’re looking for more flexibility in a diet — as overall, you’re looking to increase your consumption of low glycemic index foods.
However, it isn’t strictly eliminating foods with moderate to high glycemic index rankings. Remember to always discuss with your doctor before you decide to make significant changes to your diet.
Meagan Morris is the editor in chief of Celebribody. She's veteran health and wellness editor with over 15 years of experience. Her work has been featured in The Atlantic, Yahoo Health, Cosmopolitan, SELF, and Women's Health, among others. She spends most of her time writing, but her favorite part of the day is spent under a barbell doing squats.