Do Potatoes Raise Blood Sugar? Everything You Should Know

Potatoes may be America’s favorite vegetable, but are they good for your metabolic health? Here's everything you need to know about potatoes and blood sugar.

a woman reaching for a potato on a kitchen island
by
Julia Zakrzewski, RD
— Signos
Health & Nutrition Writer
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Updated by

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Science-based and reviewed

Published:
May 20, 2024
August 29, 2022
— Updated:
October 30, 2023

Table of Contents

Potatoes, the starchy root vegetable that is a staple for many American meals, are often a topic of debate when it comes to health. In some ways, potatoes have received an unfair reputation, associated with French fries or baked and piled with sour cream and bacon, or blamed for obesity and heart disease. 

The reality is that both the type of potato and the variety of potato can impact how it affects your health and blood sugar. Carbohydrates are foods that raise your blood sugar and provide energy. Potatoes are a complex carbohydrate, which means they take longer to break down and digest compared to simple carbohydrates like white bread or soda.

Compared to other complex carbs, like whole grains or beans, potatoes can raise blood sugar levels more quickly, so how you prepare them and how much you eat can affect blood sugar levels.

This article will dive into the details behind potatoes and blood sugar, why cooking methods can make a difference, and how you can incorporate potatoes into your diet without compromising your metabolic health.

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How Potatoes Affect Blood Sugar

Potatoes contain a class of carbohydrates called starches. These are naturally occurring molecules that are bigger than simple glucose molecules, so they take longer to break down. Different potato varieties have varying levels of carbs that could impact your blood sugars.

Different Types of Potatoes

Hundreds of potato varieties are grown and sold in America, from heirloom to more common. The most popular types in grocery stores include russet, red skin, white, gold, Yukon, purple, and sweet potatoes.

The nutritional profile of each type of potato varies, and certain varieties are better for specific cooking methods. All potatoes can be baked, but russet potatoes are usually the go-to for baked potatoes or French fries. Recipes that call for boiling potatoes often use red or white potatoes. Sweet potatoes are also incredibly versatile and can be baked, boiled, or fried.

Glycemic Index and Glycemic Load of Potatoes

The glycemic index (GI) is a rating system that helps you better understand how quickly the sugars from food will enter your bloodstream. Higher GI foods cause your blood sugar to spike more rapidly, while lower GI items keep blood sugar more stable.

According to the leaders in GI research, the glycemic index of potatoes varies:

  • High GI 70 or higher - Russet, Red Skin, Gold, Yukon, Purple
  • Medium GI 56-69 - White with skin on
  • Low G1:55 - boiled Sweet Potatoes

Glycemic load considers the total amount of carbs in a portion of food and their impact on blood sugars. It's measured by multiplying the glycemic index of a food and the number of carbs in one serving divided by 100. This calculation can help you better understand how a carb-rich food will affect your blood sugars.

Here’s how to calculate the glycemic load of a small Russet potato with 20g of carbs per serving:

  • 82 (glycemic index) x 20 grams / 100 = 16

The average glycemic load for potatoes is approximately 18. This score falls in the medium range for glycemic load.

Do Potatoes Spike Blood Sugar?

Since all potatoes are carbohydrates, every variety will raise your blood sugar to some degree, although how much can depend on many different factors, like other foods in your meal and your individual biology.

After digesting foods with carbs, the sugar (glucose) leaves the small intestine and enters your bloodstream. The amount of sugar in your blood is tightly regulated because both higher or lower than normal levels can be harmful. When blood sugar rises after meals, the pancreas releases insulin, a hormone that helps transport glucose out of your blood and into the cells.

Some carbohydrates like table sugar are quickly broken down and, therefore, spike your blood sugar more quickly. Other types of carbohydrates, like those found in whole grains and vegetables, are broken down more slowly, leading to a slower rise in blood sugar levels. This is why the glycemic index and glycemic load of foods are essential to consider. 5

As you saw above, how much a potato spikes your blood sugar can depend on the type. A potato with a high glycemic index and high GL is more likely to spike your blood sugar versus those with a lower GI, which has more health benefits.

Fiber slows down how quickly sugar from foods enters your bloodstream. It is essential for excellent blood sugar control.

raw whole white, red, and purple potatoes on a wooden table

Can People With Diabetes Have Potatoes? 

People with diabetes (both type one and type 2 diabetes) can absolutely have potatoes. In addition to tasting good, potatoes can provide essential nutrients like potassium, magnesium, and vitamin C.

If you have prediabetes or diabetes, your blood sugar stays higher than normal because your body doesn't produce enough insulin or can't use it well. The food you eat can influence blood sugar control and management, so you can make decisions based on how different foods affect your body.

As a result, registered dietitian nutritionists (RDN) recommend keeping track of how many carbohydrates you eat at each meal. For example, if you have mashed potatoes as a side dish with your dinner, keeping tabs on portion size can help reduce the impact on your blood sugar. You can also pair potatoes with protein foods like chicken or fish and extra fiber-rich veggies, which can help slow down glucose absorption into your bloodstream. 

Working one-on-one with an RDN can help you determine a personal plan for your body. The number of carbohydrate servings recommended for each meal can depend on your body size and activity needs (a serving of carbohydrates is about 15 grams, which is a little more than half of a medium potato). They can also help you visualize what a serving size looks like so you can easily manage your portion sizes.

Are There Any Risks Associated with Eating Potatoes?

Most people don’t have to be concerned about any risks associated with eating potatoes. Potatoes contain a natural toxin called glycoalkaloids. Within this family are two smaller compounds, solanine, and chaconine, but these toxins are only high in raw or sprouted potatoes. 

While consuming high amounts of solanine can cause symptoms like drowsiness, itchiness, or GI distress, cooking and removing the sprouts minimizes the risk.

Potato allergies or sensitivities aren’t as common as some other types of immune reactions, but possible. If you notice symptoms after you eat potatoes, it’s a good idea to discuss food allergy testing with your doctor.

How to Minimize the Impact of Potatoes on Blood Sugar Levels 

You can minimize the impact of potatoes on your blood sugar levels by experimenting with preparation techniques (more on this below) and by emphasizing other foods in your meals that help slow down digestion to reduce blood sugar spikes. 

Try limiting your intake of fried potato products (including potato chips) or experiment with preparing potatoes in a new way to see how you like them. Don’t forget that the skin has a lot of fiber, so try leaving it on the next time you cook your potato.

Pairing your potato with lean proteins, low-GI vegetables, and fiber can help slow down the glycemic impact of your meal and reduce your chances of a spike. 

Meal examples include:

  • Grilled fish, boiled potato, broccoli, and green bean medley.
  • Tofu, baked potato, and fresh salad.
  • Beef soup with potato cubes, carrots, cabbage, onion, and garlic.
  • Eggs with a microwaved potato and sauteed spinach, onion, garlic, and tomato on the side.  
  • Chicken, roasted potato, and a Mediterranean salad.
a baked potato alongside several dishes of toppings

How to Include Potatoes in a Healthy Diet

Potatoes can absolutely be a part of a healthy diet. If you love potatoes, use the following tips to stay within your nutrition goals while still enjoying this versatile vegetable.

Preparing and Cooking Potatoes

The way you prepare your potato can significantly impact its nutritional value, so try one of the following for a healthier alternative:

  • Limit oil
  • Use an air fryer
  • Use methods like roasting, baking, boiling, or grilling instead of frying
  • Cut into cubes to add to soup

Interestingly, cooking and cooling potatoes adds to the resistant starch in the dish. Resistant starch is a form of fiber that escapes digestion and feeds your gut bacteria. It's also less likely to spike blood sugar.

Serving Size and Frequency

Moderation and variety are always the best nutrition advice, including potatoes. A study published in the British Journal of Nutrition found that consuming one medium-sized non-fried potato has no adverse effect on blood sugar levels or heart health.

The research also found that replacing refined, processed foods with boiled or baked potatoes led to a higher intake of vitamins and fiber. In other words, mindful portions of potatoes may lead to healthier habits as part of a balanced diet.

Healthy Potato Toppings That Won’t Affect Your Blood Sugars

Of course, what you add to your potatoes also matters. Instead of heavier options, try these healthier topping alternatives:

  • Infused olive oil like garlic or chili.
  • Fresh herbs, including dill, chives, or a spoonful of fresh pesto.
  • Low-fat sour cream or a spoonful of unflavored Greek yogurt.
  • Homemade fresh salsa instead of ketchup.

9 Healthy and Nutritious Potato Swaps 

If you want to mix up your starchy vegetables or sides, try these high-fiber, low-GI swaps:

  • Sweet potatoes
  • Quinoa
  • Lentils
  • Beans
  • Legumes
  • Cauliflower
  • Carrots
  • Turnips 
  • Beets
  • Parsnips

You don’t need to skip the potatoes completely, but if potatoes are the only veggie side you gravitate towards, consider experimenting with these options. These alternatives offer a range of nutrients, such as beta-carotene and antioxidants. Additionally, these swaps can be prepared in various ways to satisfy your craving for mashed or roasted potatoes. 

Potatoes and Blood Glucose: Final Takeaways

Potatoes can be part of a healthy diet when prepared and consumed in moderation. The key lies in mindful cooking methods and portion sizes. Alternatives like sweet potatoes, quinoa, lentils, and various vegetables can provide diverse nutrients and keep your meals interesting. While large amounts of potatoes can impact blood glucose levels, balanced preparation and consumption can help reduce the impact.

You can use the Signos app and a continuous glucose monitor (CGM) to track your personal response to potato consumption and see how it fits into your overall diet. Remember that nutrition is not a one-size-fits-all approach, and what matters most is understanding how your body responds to food. With this knowledge, you can make informed decisions about your diet and overall health. 

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References

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About the author

Julia Zakrzewski is a Registered Dietitian and nutrition writer. She has a background in primary care, clinical nutrition, and nutrition education. She has been practicing dietetics for four years.

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