Oatmeal can be a nutritious addition to a balanced diet. However, choosing less-processed oats without toppings high in sugar or carbs is important to avoid raising your blood sugar levels.

A cup of cooked oatmeal (1/2 cup of dried oats) contains approximately 30 grams of carbohydrates (carbs), which can fit into a nutritious meal plan for people with diabetes. Oatmeal is high in fiber and nutrients but low in saturated and trans fats and sugar and can help you maintain a healthy blood sugar level—so long as you select a brand with less-processed oats.

This is because instant and even rolled oats have a moderate glycemic index (GI) and can raise your blood sugar levels. Some brands of instant and rolled oatmeal may have a high GI, depending on their levels of processing and added sugars.

What is the glycemic index (GI)?

The glycemic index ranks carbohydrates in foods based on how quickly they raise blood glucose (blood sugar) levels after consumption. Foods with a high GI are digested quickly, causing a rapid spike in blood sugar, while foods with a low GI are digested slowly, resulting in a gradual and steady increase in blood sugar levels. Some types of oats, such as instant or rolled varieties, have a moderate GI value and are considered not blood-sugar friendly for some people with diabetes.

Individual blood sugar responses will vary. Your body may respond to high-GI foods differently than someone else.

Additionally, GI does not take portion size into account. Eating a small portion of a high-GI food may have less of an effect on your blood sugar compared to eating a large portion of a low GI food.

Adding protein and fat to oatmeal lowers the GI. You can monitor your blood sugar before and 1 to 2 hours after eating oatmeal to learn how your blood sugar responds to different types and amounts of oatmeal.

You can enjoy oats served warm as oatmeal or cold as overnight oats. Whatever the temperature, oats may be a nutritious alternative to typical breakfast choices like cold cereal that contains added sugar. Both options typically include add-ins like nuts or fruit.

You can make oatmeal ahead of time and reheat it for a quick breakfast. You typically make overnight oats hours or days in advance.

Oat groats, which are oat kernels with the husks removed, make up oatmeal. Oats are whole grains and contain fiber and plant-based protein. The National Institute of Diabetes and Digestive and Kidney Diseases recommends people with diabetes always choose carbs high in fiber (like whole grains) and limit portion size of carbs to a quarter of the plate at each meal.

You can consume oats as:

  • steel-cut (or chopped) oats
  • rolled oats
  • “instant” oats

The more processed the oats are, as in the case of instant oats and even some rolled oats, the faster your body digests them, and the faster your blood sugar can potentially increase. Steel-cut oats are the least-processed option.

Oatmeal may help support:

  • Blood sugar management: Your body digests less processed oats slower than refined grains. This can help you avoid increasing blood sugar levels too much after eating.
  • Weight loss or maintaining a moderate weight: The American Diabetes Association recommends losing at least 5% of your body weight at diagnosis. Eating a diet that’s high in fiber and protein but lower in calories, sugar, and fat may also help promote weight loss or maintain a moderate weight.
  • Lower cholesterol: A 2023 study showed that oats might also help lower overall cholesterol levels, as well as LDL (“bad”) cholesterol. This is important because having diabetes can raise your heart disease risk.

The pros of adding oatmeal to your eating plan can include the following:

  • Less-processed oatmeal with steel-cut oats can help regulate blood sugar, thanks to the moderate to high fiber content and lower glycemic index.
  • It’s heart-healthy due to its soluble fiber content and the fact it can lower cholesterol.
  • If cooked ahead, it can be a quick and easy meal.
  • It’s moderately high in fiber, making you feel full longer and helping with weight management.
  • It’s a good source of long-term energy.
  • It can help regulate digestion.

Eating a large portion of oatmeal at once can lead to a spike in blood sugar levels, as can:

  • eating oatmeal made with highly processed oats like instant oatmeal, some varieties of rolled oats
  • prepackaged oatmeals with added sugar

Oatmeal may negatively affect health in those with gastroparesis, a health condition that causes delayed gastric emptying. For those with diabetes and gastroparesis, the fiber in oatmeal can slow stomach emptying.

Eating oatmeal can support diabetes management, especially if you eat it to replace other high-carb, high-sugar breakfast choices.

Choosing certain types of oats and preparation methods can increase the positive health benefits of oatmeal. These can include:

  • Steel-cut oats: These contain more soluble fiber, which can help regulate blood sugar. They are minimally processed to slow digestion.
  • Protein or healthy fat: Enjoy oats with a protein or healthy fat such as eggs, nut butter, or Greek yogurt. Adding 1 to 2 tablespoons of chopped pecans, walnuts, or almonds can add protein and healthy fat, which can help stabilize your blood sugar.
  • Cinnamon: Cinnamon is full of antioxidants, has anti-inflammatory properties, and may help reduce the risk of heart disease.
  • Berries: Berries contain vitamins and antioxidants and can act as natural sweeteners. They also count toward your total carb intake for your meal because all fruit contain carbs. They have a low GI, making them blood-sugar-friendly carbs.
  • Low fat milk, milk alternatives, or water: Consuming low fat or soy milk can increase nutrients without adding much extra fat. But the amount of milk used counts toward the total carb intake for your meal. If you’re trying to reduce calories and fat, you can prepare oatmeal with water.
  • Low sugar protein powder: Adding protein powder can increase protein while minimizing carbs. It can also add nutrients if you are preparing your oatmeal with water.

Some types of oatmeal and preparation methods may reduce the nutritional benefits of oatmeal or cause increases in your blood sugar. Suggestions on what to avoid can include:

  • Prepackaged or instant oatmeal with added sweeteners: While instant and flavored oatmeal can be quicker to prepare, they typically add sugar and salt and contain less soluble fiber.
  • Too much dried fruit: Just a tablespoon of dried fruit can add a high amount of carbohydrates. Some varieties also contain added sugar.
  • Too much sweetener: Adding sweeteners that contain calories, like sugar, honey, brown sugar, or syrup, can significantly raise your blood glucose levels.
  • Cream: Using cream or whole milk to make oatmeal can add extra calories and fat.

In addition to the blood sugar and heart-health benefits less-processed oatmeal offers, it can help with:

Minimally processed and unsweetened oatmeal is slow to digest, meaning that you’ll feel full longer. This can help with weight loss and weight management goals. It can also help regulate the skin’s pH, which can reduce inflammation and itchiness.

When prepared correctly, less-processed steel-cut oatmeal has many advantages that can be beneficial for many people. Those with diabetes may benefit from replacing other highly refined, sweetened breakfast cereals. As with all carbohydrate sources, be sure to pay attention to portion sizes.

Be sure to monitor your blood sugar to see how oatmeal affects you. Diabetes affects people differently.

Registered dietitians can also help individualize your meal plan to meet your specific needs.