Does Toasting Bread Get Rid of Sugar?

November 5, 2025 •

3 min read

According to a study published in the European Journal of Clinical Nutrition, simply toasting bread can significantly lower its glycemic index. This finding has led many to wonder: does toasting bread get rid of sugar entirely? The short answer is no, but the process does alter how the body processes the bread's carbohydrates.

Quick Summary

The process of toasting bread does not eliminate its sugar content, but it can beneficially lower its glycemic index. Heating bread restructures its starches into a more resistant form, which results in a slower release of glucose and a less dramatic blood sugar spike.

Key Points

No Sugar Removal: Toasting does not eliminate the sugar or carbohydrates present in bread.
Lower Glycemic Index: The primary benefit is that toasting lowers the bread's glycemic index, leading to a slower and more controlled blood sugar response.
Resistant Starch Formation: The heat from toasting converts some of the digestible starches into resistant starch, which is more fibrous and less easily absorbed.
The Freeze-Then-Toast Hack: Freezing bread and then toasting it further increases the amount of resistant starch, offering an even greater reduction in glycemic impact.
Acrylamide Risk: Burnt toast should be avoided, as overcooking can produce potentially harmful compounds like acrylamide.
Minimal Calorie Change: The calorie count per slice is not significantly altered, as the minimal weight loss is mostly due to water evaporation.

The Science of Toasting: What Actually Happens?

When you place a slice of bread into a toaster, the high heat triggers several chemical and physical changes. The most apparent change is the browning, which is primarily due to the Maillard reaction and caramelization. While these reactions alter the flavor and color, the core macronutrient composition, including the sugar, remains largely the same.

The real nutritional change is more subtle. Toasting causes some of the starches within the bread to undergo a process called retrogradation, converting them into resistant starch. Unlike regular starches, resistant starch is not easily broken down and digested in the small intestine. Instead, it behaves more like dietary fiber, moving into the large intestine where it can feed beneficial gut bacteria.

How Resistant Starch Affects Blood Sugar

This increase in resistant starch is the key to why toasted bread has a lower glycemic impact. Because the starches are more difficult to digest, the carbohydrates are released into the bloodstream more slowly. This results in a less dramatic spike in blood sugar levels compared to eating a fresh, untoasted slice of bread. For individuals with diabetes or those looking to manage their blood sugar, this can be a minor but beneficial change.

Toasting and Carbohydrate Content

It's a common misconception that toasting reduces the total carbohydrate or calorie count. While a small amount of water is evaporated, making the toast lighter by mass, the overall caloric and carbohydrate content per slice does not change significantly. A darker, burnt piece of toast might have a marginally lower calorie count due to combustion, but this is an unhealthy practice that produces harmful compounds. The focus should be on the change in glycemic response, not the raw nutritional numbers.

Optimizing Glycemic Response: Freezing and Toasting

For an even greater effect on blood sugar management, research shows that combining freezing with toasting offers a significant advantage. A study involving healthy adults found that bread that was frozen, defrosted, and then toasted had an even lower blood sugar response than bread that was only toasted.

Here’s a simple process to maximize the benefits:

Freeze the bread: Place slices of bread in the freezer, which initiates the formation of resistant starch. The cold temperature causes the starch molecules to retrograde more effectively.
Defrost or toast directly: You can either defrost the bread completely or toast it directly from frozen.
Enjoy the result: The freeze-then-toast method produces a bread that can help moderate blood sugar spikes more effectively than fresh bread.

Comparison: Fresh Bread vs. Toasted Bread


Feature	Fresh Bread	Toasted Bread
Glycemic Index (GI)	Higher GI, leading to a faster blood sugar spike.	Lower GI, resulting in a slower, more gradual blood sugar rise.
Starch Structure	Mostly digestible starch, quickly broken down into glucose.	Contains more resistant starch due to retrogradation.
Water Content	Higher, making it soft and pliable.	Lower, giving it a crisp, dry texture.
Taste Profile	Simple, mild bread flavor.	Nutty, caramelized flavor from the Maillard reaction.
Calorie Count (per slice)	Negligible difference; calorie count is not significantly affected.	Negligible difference; calorie count is not significantly affected.

Conclusion: The Nuance of Toasted Bread

In conclusion, while the myth that toasting eliminates sugar is false, the process is far from nutritionally neutral. It doesn't get rid of sugar but fundamentally changes how the bread's carbohydrates are metabolized by the body. The creation of resistant starch is a key factor, leading to a lower glycemic index and a more stable blood sugar response. For the best results, especially for those managing blood sugar, consider freezing your bread before toasting. This simple technique amplifies the production of resistant starch, offering a simple yet effective way to get more benefit from a basic dietary staple. Ultimately, focusing on whole-grain breads and mindful consumption remains the most impactful strategy for overall health.

Freezing and Toasting's Role in Reducing Glycemic Impact of White Bread

Frequently Asked Questions

No, toasting bread does not make it significantly less fattening. While a small amount of water is removed, the calorie count per slice remains virtually unchanged. The effect on weight management is linked to the slower blood sugar response, which can help control appetite.

Toasting bread is beneficial for diabetics because it lowers the glycemic index (GI). This means that the carbohydrates are broken down and absorbed more slowly, resulting in a smaller, more gradual rise in blood sugar levels compared to fresh bread.

Yes, freezing bread before toasting has been shown to be even more effective at lowering its glycemic impact. This method maximizes the formation of resistant starch, which further slows down glucose absorption.

Toasting does not change the type of sugar, but it does change the structure of the starches, which are complex carbohydrates. These starches are converted into less digestible 'resistant' starches, which the body processes differently.

Yes, lightly toasted bread is a healthier choice. Over-toasting or burning bread creates acrylamide, a potentially harmful chemical. It is always best to avoid eating burnt portions of toast.

Yes, whole-grain bread already has a lower glycemic index due to its higher fiber content. When toasted, the resistant starch effect still applies, making it an even better option for managing blood sugar than toasted white bread.

The change in flavor comes from the Maillard reaction, a chemical process where heat causes amino acids and sugars to react. This reaction creates the browning and produces a more complex, nutty flavor profile.