Carbohydrates are the main source of glucose (sugar) in the body. Your body uses glucose for energy.

If you have diabetes, prediabetes, or are just keeping a close eye on your blood sugar, it’s important to be mindful of your carbohydrate intake: Carbs increase your blood sugar. If blood sugar isn’t controlled, it can cause problems, like blurry vision, headaches, and fatigue.

Despite the energy boost you may receive from potatoes, they contain a lot of starch, a type of carbohydrate. It’s important to control your portion sizes.

Recognizing the different types of carbs and how potatoes affect your blood sugar can help you avoid blood sugar spikes.

Potatoes are considered a starchy vegetable and a healthy carb. They’re high in fiber (when including the skin), low in calories, and include vitamins and minerals.

Most potato varieties have a higher glycemic index (GI). The GI rates different foods as high (GI above 70), medium (GI of 56 to 69), and low (GI of 55 or less. The GI ratings are based on how the food affects blood sugar levels.

Different types of potatoes have different GIs:

Type of potatoGlycemic Index
baked russet potato111
instant mashed potatoes87
boiled white potato82 (average)
sweet potato70
yam54

Even though it’s a complex carbohydrate, some potatoes increase blood sugar levels faster than other types of complex carbs. This is because the body processes high GI complex carbs faster than those with a low or medium GI.

To avoid higher glucose levels, you should control your portion sizes. You don’t have to avoid potatoes completely, but moderation is important.

One baked, medium-sized russet potato contains around 31 grams of starch. To calculate starch in food, find the total carbohydrates for an item and subtract the dietary fiber and sugar from that number to determine the amount of starch.

For an adult weighing between 100 to 220 pounds who has low blood sugar, under 70 mg/dL, a general rule of thumb is that every 1 gram of carbohydrate increases blood sugar by 3-4 mg/dl.

It’s important to note that this factor can change based on your level of insulin resistance or sensitivity, sleep quality, stress level, and other foods consumed.

Based on this estimate, one baked, medium-sized russet potato containing 33g of digestible carbs may increase your blood sugar by as much as 99 mg/dl.

Carbohydrates are your body and brain’s main source of energy. Carbs are broken into three categories: fiber, starch, and sugar.

When some people decide to lose weight, they often cut carbohydrates from their diet. But all carbs are not created equal. A 2016 study on mice even found that a low-carb, high-fat diet led to weight gain and uncontrolled blood sugar in the mice.

However, some studies in humans show promise. A 2017 review of studies involving participants following low-carbohydrate (under 130 grams per day) diets found improved glucose control, A1c, triglycerides, and HDL cholesterol.

Whether you want to lose weight or watch your blood sugar, it’s important to understand the different types of carbohydrates and how to portion them correctly.

This will not only have a positive effect on your health, but it will also create a long-term sustainable process for reaching your health goals.

Starch and fiber are complex carbohydrates. Starchy carbohydrates are digested, while fiber isn’t.

Because of this, high-fiber foods can create a sense of fullness, which helps prevent overeating. Complex carbs include unrefined whole grains, beans, fruits and starchy and non-starchy vegetables. Examples include:

  • black beans
  • sweet potato with skin
  • berries
  • lentils
  • green peas
  • whole wheat bread and pasta
  • squash
  • cucumber
  • broccoli
  • spinach
  • celery
  • chickpeas
  • oatmeal

Simple carbohydrates are found in fruits (which also contain complex carbs), dairy, and sweeteners like sugar, honey, and agave.

They break down faster and are quickly absorbed by the body and used for energy. It’s best to consume simple sugars that are naturally occurring in whole food sources, like fruit.

Simple sugars are also found in refined and processed carbohydrates with a lower amount of dietary fiber. Overconsumption of added sugars, particularly in refined and processed sources, can lead to weight gain and sugar imbalances in the body.

Examples of refined and processed simple carbohydrates are:

  • white bread
  • white rice
  • sugary foods like cakes and brownies
  • sugary drinks like sodas and juices

Being mindful of total carb intake during a snack or meal with potatoes is important. Substituting other vegetables for potatoes can help you maintain a healthy blood glucose level. Or, if you’re eating potatoes, make sure you account for the serving size and amount of carbs in that serving.

Rather than bake, boil, or fry regular potatoes, prepare yams or sweet potatoes. Both are low-fat, low-calorie, and help stabilize blood sugar.

Unlike potatoes that have a high GI, sweet potatoes and yams have a low to medium GI based on how they’re prepared. Keeping the skin on the sweet potato lowers the GI more due to the fiber content.

If you have a taste for mashed potatoes, prepare mashed sweet potatoes instead. Or consider another alternative — cauliflower mashed potatoes.

Pureed cauliflower has the appearance and texture of mashed potatoes, but it’s a low GI dish. Even doing half pureed cauliflower and half mashed potatoes would lessen the post-meal blood-sugar spike.

Just because you’re watching your blood sugar doesn’t mean you have to miss out on your favorite dishes. The trick is watching what you eat and monitoring how many carbs you consume.

Potatoes contain a lot of starch and should be eaten in moderation, especially if you have diabetes or prediabetes. While you may have to decrease your potato intake, several tasty alternatives can satisfy your taste buds.

The most important thing is to manage how many potatoes you consume at one meal. This will have the greatest effect on your blood sugar and health.