Clinical Corner
Glycemic Index, Glycemic Load, and your Blood Sugar
Published: Nov. 24, 2025
5 min read
Understanding how different foods impact your blood sugar is an important part of managing Type 1 or Type 2 diabetes. Making changes to your lifestyle, such as modifying your diet, with attention to nutrition and mindful food choices, is often discussed with a physician or Registered Dietitian. Adjusting food choices and making mindful food decisions goes beyond carb counting and reading labels. Understanding concepts like glycemic load and glycemic index can provide additional guidance.
Making nutrition choices for those with diabetes is also about the quality and quantity of what you eat, which dietitians may evaluate in terms of Glycemic Index (GI) and Glycemic Load (GL), respectively. This framework can help you make food choices that support staying in your target time in range, or TIR, more often.
While GI and GL may seem complex at first, they are actually designed to simplify your understanding. By using GI and GL, you can make smarter dietary choices and spend more time in range.
What is Glycemic Index (GI)?
GI is a scale from 0-100 that measures how quickly a carbohydrate containing food raises blood glucose after eating. Food with a higher GI are digested and absorbed more rapidly, causing a quicker rise or spike in blood sugar. Foods with a lower GI are broken down more slowly, leading to a more gradual increase, or less sharp spike, in glucose levels.
- Low GI foods (55 or less) break down slowly, leading to a more gradual increase in glucose. This includes most fruits, non-starchy vegetables, legumes and whole grains.
- Medium GI foods (56-69) have a moderate impact on glucose and include whole wheat bread or brown rice.
- High GI foods (70 and above) are fast-digesting and quickly spike your glucose. These include white bread, cereals and sugary drinks.
Since GI measures the speed at which foods spike your glucose, lower GI foods are optimal and can help you increase your time in range.
What is Glycemic Load (GL)?
GL builds on glycemic index by adding an important detail: portion size. While the GI tells you how quickly a carb raises glucose, it doesn’t reflect how many carbohydrates you’re actually eating in a typical serving.
- Low GL (10 or less): minimal impact on glucose
- Medium GL (11-19): moderate impact on glucose
- High GL (20 or more): significant impact on glucose
GL combines both the quality of the carb (GI) and the quantity (grams of carbs in a serving) to give a more practical picture of a food’s real impact on glucose. For example, watermelon has a high GI because it’s digested quickly, but it’s low in carbohydrates per serving (it’s mostly water!), its GL is low. That means it won’t cause a large or sustained spike in glucose.
How do Glycemic Index and Glycemic Load work together?
Think of the two working together like driving a car: GI tells you how fast you're going, while GL tells you both your speed and the total distance you travel.
Plus, understanding GI and GL has some key benefits:
- Glucose health – Low-GI and low-GL foods help keep steadier glucose levels, which supports diabetes management and can reduce sharp glucose spikes.
- Sustained energy – Low-GI and low-GL foods break down more slowly, offering a steady release of energy that helps maintain glucose levels and helps avoid energy crashes between meals.
- Satiety and Weight Support – Low-GI choices are often higher in fiber, which promotes fullness and may help prevent overeating.
How to pick the right glycemic index foods for better diabetes management?
- Prioritize both low-GI and low-GL foods – Non-starchy vegetables, fruits like apples and berries, legumes and whole grains like quinoa help keep glucose levels steadier.
- Balance higher-GI foods – Foods like rice or potatoes, have valuable nutrients. Pairing them with protein, fiber, or healthy fats (e.g., chicken with a baked potato) can reduce the overall glycemic impact for more TIR.
- Be mindful of portions – Even low-GI foods can cause blood sugar spikes when eaten in large amounts. GL helps account for both type and amount.
- Think big picture – GI and GL can be useful tools, but they don’t capture everything. A food may test low on the scale yet still be processed or low in vital micronutrients (vitamins and minerals). Focusing on overall food quality and balance in addition to the score can account for better glucose and overall health.
How can Dexcom G7 CGM help?
The Dexcom G7 Continuous Glucose Monitoring (CGM) System shows your glucose levels in real-time, enabling you to see immediately how different foods (GI), the amounts you eat (GL) and when you eat them impact your glucose and sense of well-being. It also shows trend-arrow readouts, so you can see where your glucose level will go and can take action to avoid glucose spikes or drops. Paired with exercise, medications and/or insulin dosing, it’s an incredible tool that can teach you what works best as you adjust your diet and activity level, take medications and/or dose insulin. Empowered with that personalized knowledge, you can make better choices that can help you spend more time in range while feeling your best.
Furthermore, Dexcom G7 has been proven to help lower both A1C and increase time in range1-6. And knowing your time in range can give you a more complete picture of your glucose and how to manage your diabetes today and in the future.
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1 Battelino T, Danne T, Bergenstal RM, et al. Clinical targets for continuous glucose monitoring data interpretation: recommendations from the International Consensus on Time in Range. Diabetes Care 2019;42:1593–1603 2 Beck, RW, et al. JAMA. 2017;317(4):371-378. 3 Beck RW, et al. Ann Intern Med. 2017;167(6):365-374. 4 Martens T, et al. JAMA. 2021;325(22):2262-2272. 5 Laffel LM, et al. JAMA. 2020;323(23):2388-2396. 6 Welsh JB, et al. J Diabetes Sci Technol. 2024;18(1):143-7.