Demystifying Nutrition: How many grams of sugar are low glycemic?

October 18, 2025 •

3 min read

The common misconception that all sugars impact blood glucose in the same way overlooks the crucial role of the glycemic index (GI). The question of how many grams of sugar are low glycemic is misleading, as the impact on blood sugar depends on the type of carbohydrate, how it's prepared, and the portion size, not just the sugar content. Understanding the difference between GI and glycemic load (GL) is far more important for managing a healthy diet.

Quick Summary

This guide explains the difference between the glycemic index (GI) and glycemic load (GL) to clarify why focusing solely on grams of sugar for low glycemic eating is an inaccurate approach. It details how the GI ranks carbohydrates and how GL provides a more complete picture of a meal's impact on blood sugar levels, using specific examples to illustrate the point.

Key Points

Rethink 'Low Sugar' for Low Glycemic Eating: The concept of 'low glycemic' doesn't hinge on a specific number of sugar grams, but rather on the overall glycemic load (GL) of a food, which considers both its glycemic index (GI) and portion size.
Understand the Glycemic Index (GI): GI is a ranking of how quickly carbohydrates raise blood sugar, with a low GI being 55 or less. It’s a measure of carbohydrate quality, not total sugar.
Prioritize Glycemic Load (GL): GL offers a more realistic assessment by combining a food's GI with its carbohydrate quantity per serving, with a low GL being 10 or less. Foods can have a high GI but a low GL due to small portion size, like watermelon.
Cooking and Composition Affect GI: A food's GI is influenced by ripeness, processing, and its combination with other nutrients like fiber, fat, and protein, all of which slow sugar absorption.
Adopt a Holistic Low Glycemic Diet: Focus on swapping high-GI foods for lower-GI alternatives, combining carbohydrates with protein and fat, and prioritizing minimally processed foods to achieve a balanced, low glycemic diet.

What Is the Glycemic Index (GI)?

The glycemic index is a ranking system for carbohydrates, from 0 to 100, based on how quickly they raise blood sugar levels after consumption. A food's GI value is determined by comparing its effect on blood glucose to that of pure glucose, which is assigned a value of 100. The key takeaway is that the GI measures the quality of the carbohydrate, specifically the rate at which it is broken down and converted to glucose in the bloodstream.

Low GI (55 or less): Foods that are slowly digested and absorbed, causing a gradual rise in blood sugar.
Medium GI (56–69): Foods that are digested at a moderate speed.
High GI (70 or more): Foods that are quickly digested and cause a rapid spike in blood sugar.

Why Counting Sugar Grams Isn't Enough

The idea of a specific 'grams of sugar' target for a low glycemic diet is flawed because it ignores the nuances of how carbohydrates are processed by the body. For instance, fructose, the sugar found in fruit, has a much lower GI than maltose, a sugar in many processed foods. This means two different foods with the same number of sugar grams can have dramatically different effects on your blood sugar. Moreover, factors like a food's fat, fiber, and protein content all influence its overall GI. The fat in chocolate, for example, slows the absorption of its sugar, giving it a lower GI than some plain, high-carbohydrate starches. This shows that a simple count of sugar grams is an unreliable way to gauge a food's glycemic impact.

The More Accurate Measure: Glycemic Load (GL)

Instead of focusing on sugar grams, the more accurate and practical approach is to consider a food's glycemic load (GL). Glycemic load takes both the food's GI and its portion size into account, providing a more realistic measure of its effect on blood sugar. The formula for GL is: GL = (GI x grams of carbohydrate) / 100.

For example, watermelon has a relatively high GI of 76. However, it has a low carbohydrate density, so a typical 1-cup serving (around 11g carbs) has a GL of only 8. In contrast, a medium doughnut has a similar GI of 76, but a much higher carbohydrate content (around 23g), resulting in a GL of 17. This illustrates why GL is a superior metric for understanding a food's real-world impact on your body.

Comparison of Glycemic Index (GI) vs. Glycemic Load (GL)


Feature	Glycemic Index (GI)	Glycemic Load (GL)
Measurement	A food's potential to raise blood sugar, per gram of carbohydrate.	The total effect of a specific portion size on blood sugar.
Rating Scale	Low: <55, Medium: 56-69, High: >70.	Low: <10, Medium: 11-19, High: >20.
Key Focus	Carbohydrate quality (how fast they are digested).	Carbohydrate quantity and quality per serving.
Real-world example	Watermelon has a high GI but a low GL due to low carb density.	A large portion of a low GI food can have a high GL.

Practical Strategies for a Low Glycemic Diet

Focusing on whole, unprocessed foods and understanding how different nutrients interact can help you manage blood sugar more effectively.

Prioritize whole grains over refined ones: Choose options like steel-cut oats, quinoa, or brown rice over instant oats or white rice.
Combine carbs with protein and healthy fats: Adding protein (like nuts or lean meat) and fat (like olive oil or avocado) to a meal slows down the digestion of carbohydrates, lowering the overall glycemic response.
Eat more non-starchy vegetables and legumes: Foods like leafy greens, broccoli, and lentils are high in fiber, which helps reduce the GI of a meal.
Consider cooking methods: Cooking time and method can alter a food's GI. For instance, cooking pasta al dente results in a lower GI than overcooking it.
Choose less processed foods: The more processed a food, the higher its GI. Opt for whole fruits over fruit juice, which has had the fiber removed.

The Bottom Line

The question of how many grams of sugar are low glycemic misses the larger picture of nutritional science. A low glycemic diet is not a game of counting sugar grams but rather an approach focused on balancing meals with low-GI foods, paying attention to portion sizes, and including other nutrients like fiber, protein, and fat. This holistic approach promotes stable blood sugar levels, which is beneficial for managing weight, preventing chronic disease, and maintaining sustained energy. For more information, you can explore the University of Sydney's GI database, a reputable source for GI values.

Frequently Asked Questions

Not necessarily. A low glycemic diet focuses on consuming carbohydrates that are slowly digested and absorbed, leading to a gradual rise in blood sugar. While many sugary, processed foods are high GI, a diet can be low glycemic even with some sugar if it comes from low GI sources like certain fruits or is balanced with fiber, protein, and fat.

No, a low GI rating does not automatically make a food healthy. For example, some chocolate or fried foods have a low GI due to their high fat content slowing down digestion. It's essential to consider the food's overall nutritional value, including fat, calories, vitamins, and minerals, rather than focusing solely on its GI score.

You can find GI and GL values for many foods through credible sources like the University of Sydney's GI database or from health organizations that provide food lists. Remember that factors like ripeness and cooking method can slightly alter a food's GI.

Easily added low GI foods include leafy greens, lentils, chickpeas, apples, berries, and most whole grains like steel-cut oats and quinoa. Pairing these with protein and healthy fats can further minimize blood sugar impact.

Yes, high GI foods don't need to be completely eliminated. The key is moderation and balance. You can combine a high GI food with low GI options, protein, and healthy fats in a meal to lower its overall glycemic effect. For instance, eating white rice with a protein and vegetable curry will have a different effect than eating it alone.

Glycemic Load (GL) provides a better picture of a food's true impact on blood sugar because it accounts for a typical serving size, whereas the Glycemic Index (GI) only measures the effect of an equal amount of carbohydrates. This is why a food with a high GI, like watermelon, can have a low GL because it is not very carbohydrate-dense.

Cooking methods can significantly alter a food's GI. For example, cooking starchy foods like pasta or rice for a longer duration breaks down the starches more, increasing the GI. Conversely, cooking and then cooling certain starchy foods like potatoes or rice can create resistant starch, which has a lower GI.