Does Potato Reduce Sugar? The Truth About Potatoes and Blood Glucose

December 21, 2025 •

4 min read

Despite popular myths, a baked potato has a glycemic index (GI) value of 111, which is higher than table sugar. This high GI value indicates that potatoes are more likely to raise blood sugar levels rather than reduce them, a critical factor for those managing diabetes.

Quick Summary

Potatoes are a high-carbohydrate food that can raise blood sugar levels, contrary to the myth that they reduce sugar. Their glycemic index depends on variety and cooking method. Strategies like cooling cooked potatoes and pairing them with protein can mitigate blood sugar spikes, making them manageable for many people when consumed in moderation.

Key Points

Potato Increases Blood Sugar: Potatoes are a high-carbohydrate, starchy food that, upon digestion, raises blood glucose levels rather than lowering them.
Cooking and Cooling is Key: Cooking potatoes and then refrigerating them increases resistant starch, which dramatically lowers their glycemic impact and slows the rise in blood sugar.
Choose Waxy or Sweet Potatoes: Starchy varieties like Russets have a higher glycemic index (GI), while waxy potatoes and sweet potatoes have a lower GI, making them a better choice for blood sugar management.
Pair with Protein and Fiber: Eating potatoes as part of a balanced meal with protein, healthy fats, and fiber slows digestion and moderates blood sugar spikes.
Prioritize Healthy Cooking Methods: Boiling, steaming, and baking are better choices than frying, which adds unhealthy fats and calories that can be detrimental to heart health.
Mind Your Portions: Portion control is essential, as the total amount of carbohydrates consumed has a significant impact on blood sugar levels, regardless of preparation.

How Potatoes Affect Blood Sugar

Potatoes are a starchy vegetable, meaning they are primarily composed of carbohydrates. When consumed, these carbohydrates are broken down into simple sugars (glucose), which then enter the bloodstream. For people without diabetes, the pancreas releases insulin to transport this glucose into cells for energy. However, for those with diabetes, this process is impaired, and glucose can remain in the bloodstream for longer, leading to elevated blood sugar levels. It is this high carbohydrate content and the body's digestive process that lead potatoes to increase, not decrease, blood sugar.

The Impact of Glycemic Index (GI) and Glycemic Load (GL)

To understand how different foods affect blood sugar, nutritionists use the glycemic index (GI) and glycemic load (GL). GI ranks foods based on how quickly they raise blood sugar, while GL accounts for both the GI and the portion size.

High GI foods (70+) raise blood sugar quickly.
Medium GI foods (56-69) have a moderate effect.
Low GI foods (55 and below) cause a more gradual rise.

Many potato varieties, particularly starchy ones like Russets, have a medium to high GI. A typical baked Russet potato, for example, has a GI around 85, placing it firmly in the high-GI category. This doesn't mean they are forbidden, but it does mean that managing portion size and preparation is crucial for those monitoring blood glucose.

Strategies to Moderate the Blood Sugar Impact of Potatoes

While potatoes do not reduce sugar, there are several methods to lessen their impact on blood glucose levels. These strategies are especially important for individuals with diabetes to incorporate potatoes into a healthy diet safely.

1. The Power of Resistant Starch

One of the most effective methods to lower the glycemic impact of potatoes is to increase their resistant starch content. Resistant starch is a type of fiber that isn't digested in the small intestine but is fermented by bacteria in the large intestine. This process slows the absorption of carbohydrates into the bloodstream. You can increase resistant starch by:

Cooking and cooling: Boil or bake potatoes, then refrigerate them for at least 12 hours before eating. This process, called retrogradation, dramatically increases resistant starch, even if you reheat them later.
Serving them cold: A potato salad made with cooled potatoes is a great example of this principle in action.

2. Choosing Lower-GI Varieties

Different potato varieties have different starch compositions and, therefore, different glycemic indices. Opting for lower-GI types can help manage blood sugar spikes.

Waxy varieties: Potatoes like red, fingerling, or Carisma have a lower GI than starchy Russets.
Sweet potatoes: With a GI of around 44, sweet potatoes are often a better choice for blood sugar management than white potatoes.

3. Smart Preparation Methods

How you cook and prepare potatoes significantly influences their GI and overall health impact.

Healthy cooking methods: Steaming, boiling, or baking without added fats are the best options.
Avoid frying: Fried potatoes and chips are high in unhealthy fats and calories, which are detrimental to heart health, especially for those with diabetes.

4. Strategic Food Pairings

Pairing potatoes with other foods can help slow carbohydrate digestion and reduce the overall glycemic response of the meal.

Add protein and healthy fats: Pairing a baked potato with lean protein (like grilled chicken) and healthy fat (such as olive oil or avocado) will moderate blood sugar spikes.
Include fiber-rich foods: A large salad with your potato will add fiber, further slowing digestion.

Comparison of Potato Types and Preparation Methods

To illustrate how different factors impact potatoes' effect on blood sugar, consider the following comparison based on GI and GL values.


Attribute	Baked Russet Potato (High GI, High GL)	Boiled & Cooled Potato (Lower GI, Lower GL)
Preparation	Cooked and served hot.	Cooked, refrigerated for 12+ hours, then served cold or reheated.
Glycemic Index (GI)	Very high (approx. 85-111).	Lowered significantly (can drop below 60).
Resistant Starch	Minimal.	Increased due to retrogradation.
Effect on Blood Sugar	Rapid and significant spike.	More gradual and controlled rise.
Carb Availability	Rapidly digestible.	Slower digestion due to resistant starch.

Conclusion

In short, the answer to "does potato reduce sugar?" is no. Potatoes, as a high-carbohydrate food, will increase blood glucose levels. However, this does not mean they are off-limits for individuals monitoring their sugar intake. By understanding how the glycemic index works and implementing smart strategies like choosing the right variety, controlling portions, opting for healthier cooking methods, and leveraging the power of resistant starch through cooling, potatoes can be included as a balanced part of a healthy diet. Always prioritize whole-food preparations over processed or fried versions and consult a healthcare professional for personalized dietary advice. See this source for a comprehensive guide on diabetes-friendly recipes and tips.

Frequently Asked Questions

Yes, people with diabetes can eat potatoes in moderation as part of a balanced diet. The key is to manage portion sizes, choose lower-GI varieties like sweet potatoes, and use preparation methods that reduce their glycemic impact, such as boiling and cooling.

Boiling potatoes and then cooling them to create resistant starch is one of the most effective methods to reduce their glycemic impact. Serving them as a cold potato salad is an excellent option.

When potatoes are cooked and then cooled, the starch undergoes a process called retrogradation, which increases the amount of resistant starch. This type of starch resists digestion, slowing down the absorption of glucose into the bloodstream.

Sweet potatoes generally have a lower glycemic index (around 44) compared to many white potato varieties (like Russets, GI around 85), leading to a more gradual increase in blood sugar levels.

Pairing potatoes with sources of protein, healthy fats, and high-fiber vegetables can help slow the digestion of carbohydrates. Examples include combining potatoes with lean meat, fish, eggs, beans, or a large salad.

Yes, eating potatoes with their skin on adds dietary fiber. Fiber helps slow down the rate of carbohydrate absorption, which can lead to a more stable blood sugar level compared to eating potatoes without the skin.

Good low-carb alternatives include cauliflower (mashed, roasted), carrots, parsnips, pumpkin, and squash. These options have a lower glycemic index and fewer carbohydrates.