Understanding the Glycemic Impact: What Starches Don't Raise Blood Sugar as Quickly?

October 30, 2025 •

4 min read

According to a 2018 review, resistant starch can improve insulin sensitivity and lower blood sugar levels after meals. This reveals that certain starches have a minimal impact on glucose, prompting many to ask what starches don't raise blood sugar as significantly as others. This nuance is key for anyone managing diabetes or aiming for stable energy levels.

Quick Summary

This article explores starches with a minimal impact on blood sugar, highlighting the roles of resistant starch and fiber. It details specific low-glycemic foods, from legumes to whole grains, and explains how cooking techniques can further reduce a starch's effect on glucose.

Key Points

Embrace Resistant Starch: Starches that resist digestion, such as those found in cooled pasta or rice, act like fiber and minimize blood sugar spikes.
Prioritize Legumes: Beans, lentils, and chickpeas are high in both fiber and protein, resulting in a low glycemic impact.
Choose Whole Grains Over Refined: Opt for whole grains like oats, quinoa, and barley, which contain fiber that slows glucose absorption.
Cool Cooked Starches: Simple techniques like cooking and then cooling potatoes or rice can significantly increase their resistant starch content.
Pair Starches with Protein and Fat: Combining starches with lean protein and healthy fats further slows down digestion, ensuring a more stable blood sugar response.
Opt for Sweet Potatoes Prepared Healthily: Boiled sweet potatoes have a lower glycemic index than white potatoes, but all potatoes' GI is affected by cooking method.

Navigating the world of carbohydrates can be confusing, especially with concerns about blood sugar. While all carbohydrates are broken down into glucose, not all starches affect blood sugar levels equally. The key lies in understanding the glycemic index (GI), a measure of how quickly a food raises blood sugar, and the special properties of different starches, especially resistant starch.

The Role of Resistant Starch and Fiber

Resistant starch is a type of carbohydrate that passes through the small intestine undigested, much like soluble fiber. It travels to the large intestine, where it is fermented by beneficial gut bacteria, leading to the production of short-chain fatty acids like butyrate. Because it isn't broken down into glucose in the small intestine, it does not cause the rapid blood sugar spikes associated with other starches.

Dietary fiber, which is abundant in many healthy starches, also plays a crucial role. Fiber slows down the digestive process, which in turn slows the absorption of glucose into the bloodstream, leading to a more gradual and sustained rise in blood sugar. This prevents the dramatic peaks and crashes that can be harmful, particularly for individuals with diabetes.

Low-Glycemic Starches and How to Prepare Them

Legumes and Pulses

Legumes such as beans, lentils, and chickpeas are powerhouse starches with a low GI. Their high fiber and protein content contribute to a slow and steady release of glucose. For example, a single cup of chickpeas provides a significant amount of both fiber and protein, making them an excellent choice for stabilizing blood sugar.

Black beans: A versatile ingredient for salads, soups, and burritos, offering a low GI score.
Lentils: Great for stews, curries, and salads, with green lentils having a very low GI.
Chickpeas: Ideal for making hummus, roasting for a crunchy snack, or adding to salads for a fiber boost.

Whole Grains

Unlike refined grains that have their fiber-rich bran and germ removed, whole grains contain the entire kernel and its nutrients. This high fiber content makes them a superior choice for blood sugar management.

Oats: Steel-cut or rolled oats are lower in GI than instant varieties and are rich in beta-glucan fiber, which is particularly effective at slowing digestion.
Quinoa: This seed, often used as a grain, is a complete protein source and has a low GI.
Barley: This often-overlooked grain is high in soluble fiber, especially beta-glucan, making it a great blood sugar stabilizer.
Brown rice: A healthier, slower-digesting alternative to white rice, though portion control is still important.

Resistant Starch from Cooking and Cooling

A fascinating way to increase the resistant starch content of many foods is through a simple cooking and cooling process called retrogradation. When starchy foods like rice, potatoes, and pasta are cooked and then cooled, their molecular structure changes, making a portion of the starch resistant to digestion. This effect is retained even if the food is reheated, though some health experts recommend consuming it cold or slightly warmed.

Cooling rice: Cooked white or brown rice left to cool overnight has a higher resistant starch content than freshly cooked rice, leading to a smaller glucose response.
Potato salad: Cooling boiled potatoes transforms a significant portion of their starch, making them a better choice for blood sugar.
Overnight oats: Preparing oats without heat ensures a maximum amount of resistant starch is retained.

Comparison of Different Starch Types


Feature	Rapidly Digestible Starch (e.g., White Bread)	Resistant Starch (e.g., Cooled Potatoes)	Complex, Fiber-Rich Starch (e.g., Lentils)
GI Score	High (>70)	Low (<55)	Low (<55)
Digestion Speed	Very fast	Very slow (ferments in colon)	Slow	n	Blood Sugar Impact	Rapid, large spike	Minimal increase	Gradual, small rise	n	Fiber Content	Low	Higher (after cooling)	High	n	Gut Health	Minimal benefit	Acts as a prebiotic	Supports healthy gut bacteria	n

Sweet Potatoes vs. White Potatoes

While the GI of any potato can be influenced by cooking method, sweet potatoes often get a better rap for blood sugar. A boiled sweet potato has a significantly lower GI than a boiled white potato, primarily due to differences in their starch composition (more amylose in sweet potatoes). However, preparation is critical. Frying or baking either type can increase its GI, so boiling is often the safest bet for blood sugar control. Leaving the skin on also adds beneficial fiber.

Beyond Just the Starch

For optimal blood sugar control, it is essential to consider the overall meal. Pairing a starchy food with healthy fats and protein can further slow digestion and minimize blood sugar spikes. For instance, a meal of quinoa with lean chicken and avocado will have a much lower glycemic impact than a bowl of plain quinoa. Non-starchy vegetables like broccoli, spinach, and cauliflower are excellent fillers that add fiber and nutrients without significantly affecting blood sugar.

Conclusion: Making Smart Starch Choices

Choosing starches with a lower glycemic impact is a cornerstone of managing blood sugar. This doesn't mean eliminating them entirely, but rather prioritizing whole, fiber-rich sources like legumes and whole grains. Moreover, incorporating resistant starch through simple cooking and cooling methods can further enhance the glycemic profile of staple foods. By making informed choices about the type of starch and how it is prepared, individuals can enjoy nutritious, energy-sustaining meals without compromising their glucose control.

For more in-depth information on healthy carbohydrate choices, consult the American Diabetes Association's resources on food and nutrition guidelines. American Diabetes Association: Get to Know Carbs

Frequently Asked Questions

The Glycemic Index (GI) is a ranking system for carbohydrate-containing foods based on how quickly they raise blood sugar levels. Foods with a low GI (under 55) are digested and absorbed slowly, causing a gradual rise in blood sugar, while high-GI foods (over 70) cause a rapid spike.

No, reheating cooked and cooled starchy foods like pasta, rice, and potatoes does not eliminate the resistant starch content. The molecular change (retrogradation) that occurs during cooling is permanent and largely withstands reheating.

Legumes are packed with both dietary fiber and protein, which slow down the digestive process. This means the glucose is released into the bloodstream more gradually, preventing a sudden increase in blood sugar levels after eating.

Yes, brown rice is generally a better choice than white rice. Because it is a whole grain, it contains more fiber, which leads to a slower, more stable rise in blood sugar. However, the resistant starch in cooked and cooled white rice can still make it a better option than freshly cooked white rice.

Compared to white potatoes, boiled sweet potatoes have a lower glycemic index and cause a less dramatic blood sugar rise. Their high fiber content, especially when eaten with the skin, helps slow down sugar absorption. However, preparation matters, and frying or baking can increase their glycemic impact.

Most whole grains are excellent for blood sugar because their fiber content leads to a slower release of glucose. Examples include oats, quinoa, and barley. However, some whole-grain products, like certain breads, can still be moderate to high GI, so checking labels and opting for less processed versions is best.

For cooked starches, try making rice or pasta salad with cooled ingredients, or let potatoes cool before eating. For natural sources, make overnight oats, add lentils to soups, or snack on slightly under-ripe bananas.