How Potatoes Affect Blood Sugar

Potatoes are a popular root vegetable that is versatile to cook with. While they offer a variety of nutrients to your diet, they are starchy vegetable that could raise your blood sugars. Read how you can include potatoes in your diet without spikes.

a woman reaching for a potato on a kitchen island

Potatoes are starchy root vegetables that are a staple in the American diet. We eat them fried, baked, roasted, and boiled, but how do the carbs in potatoes dishes affect blood sugars? 

In this article, you’ll learn that different potato varieties and cooking methods can slow down how quickly they affect your blood sugars. 

Do Potatoes Raise Blood Sugar?

Potatoes contain a class of carbohydrates called starches. These are naturally occurring molecules that are bigger than simple glucose molecules. Different potato varieties have varying levels of carbs that could impact your blood sugars. 

Different Types of Potatoes

There are hundreds of potato varieties grown and sold in America. The most popular types of potatoes you might recognize from the grocery store include: 

  • Russet 
  • Red skin 
  • White 
  • Gold 
  • Yukon 
  • Purple 
  • Sweet potato 

You might have a preference for certain types of potatoes based on their nutrition profile and how you plan to cook them. Because the starch content of each potato will affect the texture of the final dish, some potatoes are better for certain types of preparation.

White and Russet potatoes have high starch content and low moisture. They are the best suited for baking. Yukon, Blue skin, and Red skin potatoes are considered medium starch potatoes and are better suited for boiling. Sweet potatoes are also better suited for boiling because it helps retain more nutrients and makes those nutrients easier to absorb.

Regardless of the type of potato, they all contain some degree of starch which may raise your blood sugars. 

Glycemic Index and Glycemic Load

The glycemic index (GI) is a rating system that helps you better understand how quickly the sugars from food will enter your bloodstream. Choosing low-GI foods as often as possible will help keep your blood sugars stable. 

According to the leaders in GI research, the glycemic index of potatoes varies1:

  • 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 

The glycemic load of a food is the glycemic index of a food multiplied by 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 a 20g of carbs per serving:

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

The average glycemic load for potatoes is approximately 18.2 This score falls in the medium range for glycemic load. 

Do Potatoes Spike Blood Sugar?

A potato with a high GI and high GL is more likely to spike your blood sugars. Generally, potatoes have a medium GL, but the varieties with a high GI could still spike your blood sugars if you eat a large volume. 

To decrease the chances of experiencing a blood sugar spike, pair your potato with lean protein and other low-GI vegetables

The protein and additional fiber will help slow down the glycemic impact of your meal and reduce your chances of a spike. 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.

The Signos app can help you track your servings and macronutrient intake. It will offer customized feedback to help you meet your nutritional requirements and prevent you from going overboard in any of the food groups. 

<p class="pro-tip"><strong>Read about </strong> <a href="/blog/garlic-lower-blood-sugar">how garlic can help lower blood sugar</a>.</p>

Health Benefits of Potatoes

Despite their medium-high GI rating, potatoes offer a variety of nutrients and vitamins that help keep you healthy. 

Important Vitamins and Minerals 

All of these vitamins and minerals are an important part of your daily diet. Potatoes contain: 

  • Beta carotene is a precursor to vitamin A and an antioxidant.3 
  • Vitamin C is an important antioxidant that supports immune function.4 
  • Potassium is an electrolyte that regulates blood pressure, maintains fluid balance, and regulates heartbeats.5
  • Folate is concentrated in the skin of a potato and helps maintain general health.6  
  • Sweet potatoes have higher levels of B5, a vitamin involved in the metabolism of carbohydrates and fats.7 
  • B6 helps with red blood cell formation and is found in most foods.8

Potatoes contain smaller amounts of thiamin, riboflavin, folate, magnesium, iron, and zinc. Leaving the skin on will help increase the nutritional value and fiber content of the vegetable. 

<p class="pro-tip"><strong>Read more about </strong> <a href="/blog/vitamins-and-minerals-weight-loss">vitamins and minerals that may help with weight loss</a>.</p>

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
Potatoes with darker color (like red or purple) tend to have more antioxidants than white potatoes.

Potatoes Have Phenolic Compounds 

Phenolic compounds are a group of molecules that contain at least one phenol element. These groups are potent sources of antioxidants that can help keep you healthy. Examples of phenolic compounds in potatoes include: 

  • Chlorogenic acid, which may reduce your risk of stroke, cancer, heart diseases, Alzheimer’s, and Parkinson’s disease.9 
  • Flavonols. 
  • Anthocyanins. 

By themselves, potatoes are an affordable option packed with essential vitamins, minerals, and fibers. When paired with other non-starchy vegetables such as tomatoes and avocados, you can enhance nutrient absorption. 

Are There Any Risks Associated with Eating Potatoes?

Potatoes contain a natural toxin called glycoalkaloids.10 Within this family are two smaller compounds called solanine and chaconine. 

Raw potatoes and sprouted potatoes contain higher levels of solanine. If consumed in high doses, the toxin can lead to: 

  • Drowsiness
  • Itchiness around the neck 
  • Hypersensitivity 
  • Abdominal pain 
  • Vomiting
  • Diarrhea 

Cooking your potatoes and removing any sprouts decreases the concentration of the toxin and will make them safe to eat. 

It is very rare that someone would have an allergy to potatoes, but not impossible. If you suspect you are having an allergic reaction, follow up with your health care provider and ask for a food allergy test.

How to Include Potatoes in a Healthy Diet

Potatoes can be prepared in advance and refrigerated for the rest of the week. You can reheat them in the microwave or use your stovetop. 

Preparing and Cooking Potatoes

The way you prepare your potato will have a significant impact on its nutritional value. Here are healthier ways to prepare your potatoes: 

  • Baking with small amounts of oil. 
  • Air frying at home with one teaspoon of oil.
  • Grilling on the barbecue. 
  • Roasting in the oven with your favorite seasonings.
  • Mashing potatoes with skim milk and garlic powder. 
  • Boiling whole small potatoes and drizzling with olive oil and fresh herbs. 
  • Cutting into cubes and adding to soups. 

Longer cooking times tend to bring down the GI of a potato. Studies at the University of Sydney observed a significantly lower GI in sweet potatoes that had been baked for thirty minutes compared to a sweet potato baked for thirteen minutes. 

a baked potato alongside several dishes of toppings
Baking or microwaving potatoes preserves more nutritional value compared to boiling or frying.

Serving Size and Frequency

The British Journal Of Nutrition studied how much potato was safe to eat, without risking your health, and released their findings in 2020.11They stated that one medium-sized non-fried potato will not negatively affect blood sugars or heart health. 

They found that people fared very well when they replaced refined processed foods with boiled or baked potatoes. Participants had higher vitamin and fiber intake, which helped maintain health. 

<p class="pro-tip"><strong>Learn about </strong> <a href="/blog/ultra-processed-foods">how ultra-processed foods affect blood sugar</a>.</p>

Healthy Potato Toppings That Won’t Affect Your Blood Sugars 

How you season your potatoes will also impact their nutritional quality. Opting for a low-fat baked potato but covering it in bacon, cheese, and sour cream will, unfortunately, add unnecessary calories and salt to your dish. Instead, try these healthier alternatives:

  • Infused olive oil like garlic or chili. 
  • Fresh herbs including dill or chives. 
  • Low-fat sour cream or a spoonful of unflavored greek yogurt. 
  • Homemade fresh salsa instead of ketchup. 
  • A spoonful of pesto. 
  • Sweet potato pairs well with cumin and cinnamon. 

How to Safely Store Potatoes 

Potatoes need room to breathe; otherwise, moisture can build up and they can start to sprout. Keep them in a bag that allows for air to flow through (a classic potato sack is made out of burlap), or place them in an open bowl and store them in your pantry. 

If you live in a hot climate you may consider leaving them in the refrigerator to prevent them from spoiling. 

Potatoes can be frozen or vacuum-sealed in preservation jars. These methods will extend the shelf life of your vegetables, and their nutritional value should not be affected. 

Potatoes and Blood Glucose: Final Takeaways

Different potatoes and cooking methods will impact the GI and GL of the vegetable. Cooking your potatoes for longer (baking, boiling, roasting) tends to lower the GI score for the food. 

Allowing your potatoes to cool after cooking can increase the resistant starch. Resistant starches are not fully digested therefore less sugars from food enter your bloodstream.12This may help to stabilize your blood sugar levels and increase your metabolic health. 

Portion sizes matter when it comes to managing your blood sugars. One medium-sized non-fried potato a day can fit into a balanced diet, but you don’t have to eat one every day if you don’t want to. 

Here are some easy ways to minimize the potential impact of potatoes on blood glucose: 

  • Stop or limit your consumption of fried potato products (including potato chips). 
  • Pair your potato with a lean protein and plenty of other vegetables to balance your meal. 
  • Prepare potatoes in new ways to see how you like them. 
  • Leave the skin on the next time you cook a potato. 
  • Replace high-fat and high-sugar toppings with healthier alternatives listed in the article. 

Challenge yourself to get creative in the kitchen and try one new recipe for potatoes this week.

<p class="pro-tip"><strong>Explore </strong> <a href="/blog-category/recipes">healthy and low-glycemic recipes from Signos</a>.</p>

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References

  1. GI Search – Glycemic Index. (n.d.). The University of Sydney GI Research. Retrieved August 2022, from https://glycemicindex.com/gi-search/?food_name=potato&product_category=&country=&gi=&gi_filter=&serving_size_(g)=&serving_size_(g)_filter=&carbs_per_serve_(g)=&carbs_per_serve_(g)_filter=&gl=&gl_filter= 
  2. Andersen, S., Heller, J., Hansen, T., & Raben, A. (2018). Comparison of Low Glycaemic Index and High Glycaemic Index Potatoes in Relation to Satiety: A Single-Blinded, Randomised Crossover Study in Humans. Nutrients, 10(11), 1726. https://doi.org/10.3390/nu10111726 
  3. Bohn, T., Desmarchelier, C., El, S. N., Keijer, J., van Schothorst, E., Rühl, R., & Borel, P. (2019). β-Carotene in the human body: metabolic bioactivation pathways – from digestion to tissue distribution and excretion. Proceedings of the Nutrition Society, 78(1), 68–87. https://doi.org/10.1017/s0029665118002641 
  4. Carr, A., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, 9(11), 1211. https://doi.org/10.3390/nu9111211
  5. Nomura, N., Shoda, W., & Uchida, S. (2019). Clinical importance of potassium intake and molecular mechanism of potassium regulation. Clinical and Experimental Nephrology, 23(10), 1175–1180. https://doi.org/10.1007/s10157-019-01766-x 
  6. Robinson, B., Sathuvalli, V., Bamberg, J., & Goyer, A. (2015). Exploring Folate Diversity in Wild and Primitive Potatoes for Modern Crop Improvement. Genes, 6(4), 1300–1314. https://doi.org/10.3390/genes6041300 
  7. Tahiliani, A. G., & Beinlich, C. J. (1991). Pantothenic Acid in Health and Disease. Vitamins & Hormones, 165–228. https://doi.org/10.1016/s0083-6729(08)60684-6 
  8. Brown, M. J., Ameer , M. A., & Beier, K. (2022). Vitamin B6 Deficiency. In StatPearls. StatPearls Publishing.
  9. Hellmann, H., Goyer, A., & Navarre, D. A. (2021). Antioxidants in Potatoes: A Functional View on One of the Major Food Crops Worldwide. Molecules, 26(9), 2446. https://doi.org/10.3390/molecules26092446 
  10. Dolan, L. C., Matulka, R. A., & Burdock, G. A. (2010). Naturally Occurring Food Toxins. Toxins, 2(9), 2289–2332. https://doi.org/10.3390/toxins2092289 
  11. Johnston, E., Petersen, K., & Kris-Etherton, P. (2020). Daily intake of non-fried potato does not affect markers of glycaemia and is associated with better diet quality compared with refined grains: A randomised, crossover study in healthy adults. British Journal of Nutrition, 123(9), 1032-1042. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/daily-intake-of-nonfried-potato-does-not-affect-markers-of-glycemia-and-is-associated-with-better-diet-quality-compared-to-refined-grains-a-randomized-crossover-study-in-healthy-adults/1C2933542FFF2C37C886A9D0FDF83091 
  12. Raben, A., Tagliabue, A., Christensen, N. J., Madsen, J., Holst, J. J., & Astrup, A. (1994). Resistant starch: the effect on postprandial glycemia, hormonal response, and satiety. The American journal of clinical nutrition, 60(4), 544–551. https://doi.org/10.1093/ajcn/60.4.544

About the Author

Julia Zakrzewski Headshot
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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