Nutrition Diet: How do they reduce carbs in potatoes?

October 22, 2025 •

4 min read

While often viewed as high in carbs, a 2016 study found that resistant starch content in potatoes can be significantly increased through specific cooking methods. This offers a powerful and scientific answer to the question, how do they reduce carbs in potatoes?

Quick Summary

Several cooking and preparation methods, primarily involving cooling cooked potatoes, convert starches into indigestible fiber, effectively lowering their glycemic impact and usable carbohydrate content.

Key Points

Cook and Chill: The most effective way to lower the glycemic impact is by cooking potatoes and then cooling them completely to form resistant starch.
Resistant Starch is Key: This indigestible starch functions like a fiber, providing fewer usable calories and a gentler blood sugar response.
Add Acidity: Incorporating vinegar or lemon juice into potato dishes can significantly reduce the glycemic index.
Pair with Protein and Fat: Combining potatoes with protein and healthy fats helps slow digestion and lessen blood sugar spikes.
Choose Wisely: Opting for lower-GI waxy potato varieties can be a good strategy for managing carbohydrate intake.

The Science of Carb Reduction

Potatoes are primarily made of starch, a complex carbohydrate that our bodies break down into glucose for energy. The goal of 'reducing carbs' in potatoes is not to eliminate them entirely, but rather to change the structure of the starch so it resists digestion. The key lies in a process called retrogradation, where starches, once cooked and cooled, re-crystallize into a form known as resistant starch (RS3). This type of starch passes through the small intestine largely undigested, behaving more like dietary fiber. This process has several benefits, including a lower calorie count and a reduced spike in blood sugar levels.

Cooking and Cooling for Resistant Starch

One of the most effective and scientifically supported methods for lowering the glycemic impact of potatoes is the simple cook-and-cool technique. This process maximizes the creation of resistant starch.

Boil and Chill: Cook potatoes (with or without the skin) as you normally would. Once cooked, allow them to cool completely, preferably in the refrigerator overnight. This cooling period triggers the formation of resistant starch. Even if you reheat the potatoes the next day, the resistant starch structure remains largely intact, and the glycemic response will still be lower than that of freshly cooked potatoes.
Add Acidity: For an even greater reduction in glycemic index, consider adding an acidic dressing. A 2005 study found that adding vinegar to cold-stored potatoes significantly lowered the glycemic and insulinemic response. Incorporate vinegar-based dressings into potato salads or add a splash of vinegar to the water while boiling.
Method Matters: Research indicates that the specific cooking method can influence resistant starch formation. Some studies have found that baked potatoes, when subsequently chilled, can produce slightly more resistant starch than boiled and chilled ones, though both methods are effective.

Pre-Cooking Starch Removal Techniques

These methods focus on removing some of the surface starch before cooking, which can improve texture and slightly reduce carb load, especially for recipes where crispiness is desired.

Soaking in Cold Water: Cut potatoes and rinse them in a bowl of cold water. Soaking them for a few hours, or even overnight, can help draw out some of the soluble starch. You will notice the water becoming cloudy. Rinsing and replacing the water a few times helps remove even more starch.
Blanching: An alternative to long soaking is blanching. Briefly boil the potato pieces in hot water for a few minutes. The heat causes the starch granules to burst and release into the water. Drain the water and rinse with cold water to stop the cooking process.

Choosing the Right Potatoes and Pairings

Beyond cooking methods, smart choices at the grocery store and during meal preparation can make a difference.

Select Lower-GI Varieties: The glycemic index of potatoes varies by type. Waxy potatoes, such as fingerlings or new potatoes, tend to have a lower GI than starchy russet or Idaho varieties. Sweet potatoes also generally have a lower glycemic index.
Combine with Other Nutrients: Pairing potatoes with healthy fats, proteins, and fiber-rich vegetables can help blunt blood sugar spikes. The fat and protein slow down digestion, reducing the overall glycemic load of the meal. For example, enjoy a small portion of potatoes with a generous helping of leafy greens dressed in olive oil.

Comparison of Potato Preparation Methods


Preparation Method	Key Effect	Benefits	Considerations
Boil, Chill, Reheat	Creates resistant starch (RS3) through retrogradation.	Lower glycemic impact, fewer usable calories, supports gut health.	Requires advanced preparation; may not be suitable if you need to eat immediately.
Soaking (Pre-Cooking)	Physically removes soluble starches.	Improves crispiness of fried or roasted potatoes, slightly reduces carbs.	Minimal effect on overall carb load compared to resistant starch creation.
Add Acid	Acetic acid slows stomach emptying.	Further lowers glycemic response, complements the cooling method.	Alters flavor profile; might not work for all recipes.
Combine with Protein/Fat	Slows digestion and glucose absorption.	Blunts blood sugar spikes, increases satiety.	Does not reduce the carb count in the potato itself; depends on the pairing.
Boil Only	Lowers GI compared to baking but less effective than cooling.	Still a healthier cooking method than baking for glycemic control.	The starches remain largely digestible and have a higher glycemic impact than cooled potatoes.

Practical Steps to Reduce Carb Impact

To make potatoes a more manageable part of a carb-conscious diet, follow these steps:

Boil your potatoes (with skins on for extra fiber), then refrigerate them overnight to maximize resistant starch formation.
The next day, use the chilled potatoes for a cold potato salad or reheat them in the oven or microwave.
When boiling potatoes, add a splash of vinegar to the water to further reduce the glycemic response.
Always eat potatoes as part of a balanced meal, paired with protein (like grilled chicken or chickpeas) and healthy fats (such as olive oil or avocado) to slow digestion.
Choose waxy or sweet potatoes over starchy russets when possible for a lower inherent glycemic index.

Conclusion

For those managing their carbohydrate intake, the classic potato doesn't have to be off-limits. By understanding the science behind resistant starch and applying smart cooking techniques, it's possible to significantly reduce the glycemic impact of this popular food. Simply cooking, cooling, and even reheating potatoes creates a healthier, more fibrous version that provides sustained energy and supports gut health. Combining these techniques with mindful pairings and careful potato variety selection empowers you to enjoy potatoes as part of a balanced and nutritious diet.

Learn more about resistant starch and its health benefits from the National Institutes of Health. [https://pubmed.ncbi.nlm.nih.gov/16034360/]

Frequently Asked Questions

Boiling itself does not significantly reduce the overall carbohydrate content, but the subsequent chilling process creates resistant starch, which has a lower glycemic impact on the body.

As potatoes cool after being cooked, the starches undergo a process called retrogradation. They reorganize into a crystalline structure that is resistant to digestion in the small intestine, acting like a dietary fiber.

Yes, you can reheat cooled potatoes. The resistant starch structure that formed during cooling remains largely intact even after reheating, meaning the reheated potatoes will still have a lower glycemic impact than freshly cooked ones.

Soaking cut potatoes in cold water helps wash away excess surface starch. While this has a minor impact on overall carbs, it primarily helps achieve a crispier texture when the potatoes are fried or roasted.

While all potatoes contain carbs, waxy varieties like fingerlings or new potatoes typically have a lower glycemic index than starchy Russet potatoes. Choosing these can be a better option for blood sugar management.

Adding an acid like vinegar to potatoes can significantly lower the meal's overall glycemic response by slowing down stomach emptying and digestion. It's a proven method for blunting blood sugar spikes.

Because resistant starch is not fully digested and provides fewer usable calories, it can help increase feelings of fullness and contribute to weight management efforts.