Does Gluten-Free Have Low GI? Separating Fact from Marketing

November 22, 2025 •

3 min read

According to a 2021 study, approximately 60.7% of gluten-free bread samples tested had a high glycemic index, revealing a common misconception about gluten-free products and low GI status. This is because the GF label does not automatically equate to a low GI for effective blood sugar management.

Quick Summary

The nutritional value of gluten-free foods varies greatly based on ingredients and processing. Many substitutes use high-GI starches like white rice flour, leading to rapid blood sugar spikes. It is crucial to evaluate specific food ingredients rather than relying on a general label.

Key Points

Not Inherently Low GI: A gluten-free label does not guarantee a low glycemic index, and many processed GF products are higher in GI than their conventional counterparts.
Refined Starch Impact: Processed GF foods often use high-GI starches like white rice flour, potato starch, and tapioca starch, which can cause significant blood sugar spikes.
Fiber and Protein Deficiency: Many GF substitutes contain lower fiber and protein, both of which are crucial for slowing digestion and regulating blood glucose levels.
Choose Whole Foods: The best approach for a low-GI, gluten-free diet is to focus on naturally GF and unprocessed whole foods such as vegetables, fruits, legumes, and lean proteins.
Ingredient Awareness: For packaged GF products, prioritize those made with low-GI, high-fiber grains and flours like buckwheat, quinoa, and legume flours.
Balance Meals: The overall glycemic load of a meal can be managed by pairing higher-GI items with protein, healthy fats, and low-GI foods to regulate glucose absorption.

Understanding the Glycemic Index

The glycemic index (GI) is a system for ranking carbohydrate-containing foods based on how quickly they raise blood sugar levels. The scale runs from 0 to 100, with pure glucose at the top. Foods are categorized as low GI (55 or less), medium GI (56-69), or high GI (70 or more). The rate of absorption is influenced by several factors, including fiber, protein, fat content, processing, and the type of starch. Low-GI foods are digested and absorbed more slowly, leading to a gradual rise in blood glucose and insulin levels, which is beneficial for managing conditions like diabetes and for weight control.

The Common Misconception About Gluten-Free Foods

Many consumers, and even some healthcare professionals, assume that a gluten-free (GF) product is inherently healthier or has a lower GI. This is often incorrect, as many processed GF foods use ingredients that compensate for the lack of gluten, frequently involving the replacement of wheat with high-GI starches that can negatively impact blood sugar management.

Why Processed Gluten-Free Products Can Have a High GI

Refined Starch Replacements: Processed GF items often utilize refined flours and starches such as white rice flour, potato starch, tapioca starch, and cornstarch, which are low in fiber and quickly raise blood sugar.
Lower Fiber and Protein: Many GF alternatives have less fiber and protein, both of which slow digestion and help regulate blood sugar levels.
Added Sugars and Fats: To improve taste and texture, some processed GF foods contain added sugars and fats, contributing to a higher caloric and glycemic load.

The Higher GI of Many Gluten-Free Items

A systematic review found that over 60% of gluten-free bread samples had a high GI. Another study showed a control gluten-free biscuit had a high GI of 77. This demonstrates that the composition of many processed GF products often results in a higher GI than comparable gluten-containing items.

Finding Truly Low-GI, Gluten-Free Foods

A low-GI, gluten-free diet is achievable by focusing on whole foods. Incorporating ingredients high in fiber and resistant starches can also help lower the GI of formulated GF products.

Ingredients that can help lower the GI in GF products:

Legume flours (lentils, chickpeas, beans)
Pseudocereals (buckwheat, quinoa, amaranth)
Resistant starch
Sourdough fermentation
Fibers and additives (psyllium, inulin)

Comparison of Gluten vs. Gluten-Free Alternatives


Food Item	Typical Gluten-Containing GI	Typical Processed Gluten-Free GI	Low-GI Gluten-Free Alternative
White Bread	~75	~77-83	Buckwheat bread (~50)
Pasta	~43 (al dente)	Often higher	Legume-based pasta (lentil, chickpea)
Biscuits	Varies, e.g., Oat biscuits lower	Often high GI (Digestive 83)	GF biscuits with maltitol, inulin, and resistant starch (GI as low as 33)
Cereal	Cornflakes (~81)	Many instant or refined options are high GI	Rolled or steel-cut oats (certified GF), quinoa porridge

How to Manage Your Diet Effectively

For those managing blood sugar, especially individuals with both celiac disease and diabetes, it's crucial to read labels carefully rather than assuming a GF product is low GI. Resources like the Celiac Disease Foundation offer guidance.

Focus on naturally low-GI, gluten-free foods: Choose whole foods like fruits, vegetables, eggs, lean meats, and legumes.

Select high-fiber, low-GI grains: Opt for processed GF grains made with ingredients like quinoa, buckwheat, and sorghum.

Balance your meals: Combine higher-GI foods with protein, healthy fats, and low-GI foods to stabilize blood sugar.

Conclusion

Not all gluten-free products have a low GI. Many processed GF items use high-GI ingredients and lack the fiber found in whole grains, which can negatively impact blood sugar management. A genuinely low-GI, gluten-free diet emphasizes whole foods such as vegetables, legumes, and specific pseudocereals, while limiting refined GF products. Understanding ingredient differences allows for informed choices to manage health effectively while avoiding gluten.

Frequently Asked Questions

No, gluten-free is not automatically low GI. Many processed gluten-free products use refined flours like white rice and potato starch, which are high on the glycemic index and can cause blood sugar to rise quickly.

To compensate for the lack of gluten, which provides structure and texture, manufacturers often use low-fiber, refined starches and sometimes add extra sugar or fat, all of which contribute to a higher glycemic index.

Naturally gluten-free grains and pseudocereals like buckwheat, quinoa, and millet generally have a lower glycemic index compared to highly processed rice or corn-based GF options.

Gluten is a protein and does not directly affect blood sugar levels. The impact on blood sugar comes from the carbohydrates in the food, and many gluten-free alternatives contain easily digestible, high-GI carbohydrates.

Yes, but you must be intentional about your food choices. Focus on naturally gluten-free whole foods such as vegetables, fruits, legumes, lean meats, and select whole grains. Read labels carefully and limit processed GF items.

Individuals with both conditions should prioritize whole, unprocessed foods and choose gluten-free options that are also high in fiber and protein. Regular monitoring of blood sugar levels after eating new GF foods is also advised.

You can lower the glycemic impact of a meal by including sources of protein, healthy fats, and fiber. For example, pair a GF carbohydrate source with lean protein, vegetables, or legumes to slow down digestion and stabilize blood sugar.