Carbs in Potatoes: Do Potatoes Fit in a Ketogenic Diet?

Potatoes are one of the most highly-consumed side dishes in North America. From French fries to potato salad and tater tots to mashed potatoes, every variation is an American family favorite comfort food. Given its versatility, it’s almost impossible to get bored with this delicious starch.

However, if you’re starting the keto diet (or any other low-carb diet), you’re probably wondering, “How many carbs in potatoes?” Below, you’ll learn all about the carbs in potatoes and whether they hold a place on the keto diet.

Carbs in Potatoes: The Bitter Truth

Are potatoes low-carb? 

Not one bit.

There are quite a few carbs in potatoes. They are one of the few foods that rank more highly than white bread on the glycemic index — a tool that measures a food’s impact on blood sugar. 

On a scale of 0–100, a boiled potato has a glycemic index of 78 while a slice of bread comes in at 75[*]. It has a glycemic load of 28 while white bread has a glycemic load of 10 and white rice scores 33[*]. When you eat a potato, you spike your blood sugar more than when you eat bread.

How Many Carbs Are in A Potato? 

The serving size of a potato is one medium potato. One serving contains 37 grams of total carbohydrates and just 4.5 grams of dietary fiber, giving you a net carb intake of 32.5 gram[*]. 

It contains a little more than 4 grams of protein and less than 1 gram of fat. Most individuals consume roughly 20 grams of carbs per day to stay in ketosis — so a single potato would take up your entire carb allotment for the day.

Are Sweet Potatoes High in Carbs?

Potatoes are a starchy vegetable known as tubers. They grow below the ground and are known for being a high-carb food. Different kinds of potatoes (red, sweet, and russet potatoes) all have different micronutrients and macronutrients.

Both regular and sweet potatoes originated from Central and South America. There are about 4,000 known varieties of potatoes and about 3,000 varieties of sweet potatoes Both white and sweet potato varieties can vary in size, texture, carb count, micronutrients, and taste. 

What’s the nutritional difference between sweet potatoes and white potatoes? There are three main ways in which they differ — carb count, vitamins, and starch. 

#1: Sweet Potatoes Contain Fewer Carbs Than White Potatoes

One medium sweet potato contains roughly 23.6 grams of total carbohydrates and 3.8 grams of fiber, giving you 20 grams of net carbs[*]. While this is significantly less than a white potato, sweet potatoes still rank highly on the glycemic index, with a score of 63[*]. To compare, white potatoes have 32.8 grams of net carbs per potato.

#2: Sweet Potatoes Contain More Vitamins Than White Potatoes

The next way sweet potatoes differ from white potatoes is that sweet potatoes have significantly more vitamins. Sweet potatoes contain over 400% of your daily value of vitamin A, 37% for vitamin C and 16% for vitamin B6[*]. By comparison, white potatoes contain 0% of vitamin A, 28% for vitamin C, and 27% for vitamin B6[*].

#3: White Potatoes Contain More Resistant Starch Than Sweet Potatoes

Finally, compared to sweet potatoes, regular potatoes have more resistant starch, which means the starch can’t be completely digested. Most starches, like bread, cakes, and cereal, are rapidly digested by your body. 

Resistant starch, on the other hand, “rejects” digestion — it goes straight to the colon rather than being digested by the small or large intestine[*].

While research is still being gathered on resistant starch, white potatoes have more resistant starch than sweet potatoes. This means it might impact your blood glucose less than originally believed[*].

Health Benefits of Potatoes

Contrary to what you may have heard in the past, potatoes do have some benefits. The three biggest health benefits of potatoes are:

1. Improved bone health
2. Improved blood pressure
3. Reduced inflammation

#1: They Improve Bone Health 

Potatoes are a strong source of iron, calcium, phosphorus, magnesium, and zinc. 

Here are the amounts of these nutrients in one potato: 

• Iron: 3.2 mg (18% daily value)
• Phosphorus: 209 mg (21% daily value) 
• Magnesium: 83.7 mg (21% daily value) 
• ​Zinc: ​​​1.1 mg (7% daily value)

These are all known to help improve and build bone strength and structure[*][*][*][*][*].

#2: They Improve Blood Pressure 

The second health benefit of potatoes is they can help widen blood vessels and therefore lower blood pressure.

One whole potato contains 1,600 mg of potassium — that’s about 46% of your daily recommended intake. And, since potassium has the ability to widen blood vessels, they can improve your blood pressure that way as well[*]. 

#3: They Fight Inflammation 

Potatoes are strong source of choline. In fact, potatoes contain about 57 mg of choline. Choline helps fight off inflammation as well as maintaining the structure of cell membranes, absorbing fats and helping early brain development[*].

Potato Substitutes for Low-Carb Diets

If you’re looking for an alternative to potatoes, sweet potatoes are a go-to substitute. Packed with nutrients, they offer a clean carbohydrate option.

There are other low-carb vegetables that offer an even better alternative than sweet potatoes. These include:

• Cauliflower: Mashed cauliflower makes an excellent substitute for mashed potatoes. Cauliflower is filled with antioxidants, helps fight inflammation, and could even prevent the growth of cancerous tumor cells[*].
• Celery root: Celery root makes a great alternative to french fries. Plus, a 100-gram serving contains just 7 grams of net carbs.
• Daikon radish: Daikon is also a good source of vitamins A, C, E, and B6. It contains potassium, magnesium, calcium, and iron[*]. If you slice it thinly, it makes a great alternative to scalloped potatoes.
• Rutabaga: Rutabaga is perfect for individuals on a low-carb or ketogenic diet, containing only 5 grams of net carbs and 35 calories per 100 grams[*]. Shred with a cheese grater, then fry in a skillet with a little olive oil for a great hash browns substitute.
• Turnips: Turnips are a great source of antioxidants and fiber, but those aren’t the only benefits they provide. Turnips are loaded with vitamin C, iron, calcium, and vitamin K[*]. Like cauliflowers, they make a great alternative to mashed potatoes.
• Kohlrabi: Kohlrabi is full of nutrients and minerals such as copper, potassium, manganese, iron, and calcium, and is rich in vitamins including vitamins C, B, A, and K[*]. It tastes great roasted, similar to breakfast potatoes.

If you are on a low-carb diet or simply want to prioritize healthy eating, all of the above options make excellent low-carb alternatives.

Carbs in Potatoes: You Have Plenty of Alternatives

The bottom line is that there are lots of carbs in potatoes and they should be avoided on a keto diet. While they do contain several health benefits, the carb count is simply too high.

To maintain a healthy diet, choose a low-carb alternative to white potatoes, such as cauliflower, rutabaga, or turnip. 

While sweet potatoes are known as a good carb option, they are still too high-carb for keto. The alternatives mentioned will not spike your blood sugar and can be used in several keto recipes. And the best part — they taste just like regular potatoes.