What Are the 5 Worst Foods for Blood Sugar?

Do you feel shaky an hour after eating a bag of vending machine pretzels? Do people suggest you get a snack when you get a little cranky? Your shakiness and moodiness may occur because of blood sugar fluctuations and your food choices.

Keeping blood sugar levels, also called blood glucose, steady may benefit your energy levels, mood, and overall health. What you eat affects your blood glucose levels, causing blood sugar spikes and dips, especially for people with diabetes.

Learn about the five worst foods for blood sugar.

Understanding glycemic index

Not all foods affect blood sugar in the same way. Carbohydrate-containing foods, especially those that are highly processed and contain a high amount of added sugar, have the most significant effect on blood sugar levels. Some carbs digest slowly, providing a steady dose of glucose, while others digest fast, causing blood sugar spikes.

The glycemic index (GI) is a ranking system based on a scale of 0–100 that measures how fast carbohydrate-containing foods raise blood sugar levels. The carbohydrate-rich foods fall into one of three categories:

• Low glycemic foods: 0–55
• Moderate glycemic foods: 56–69
• High glycemic foods: 70–100

Low glycemic foods like less processed oatmeal cause a gradual rise in blood sugar levels, while high glycemic foods like white bread can cause a rapid increase in glucose levels. Eating more low-GI foods and balancing meals may prevent the highs and lows in blood sugar. Eating more balanced meals further regulates glucose absorption, provides sustained energy, and prevents rapid spikes.

People with diabetes may use the glycemic index as one of the tools to help manage blood glucose levels, along with carb-counting, portion control, and medication. Diabetes causes high blood sugar due to problems related to insulin, the hormone that helps transfer glucose from the blood into the cell. People with diabetes produce little to no insulin, or they have insulin resistance (cells no longer respond to insulin). Eating more low-glycemic foods may also help people with prediabetes prevent type 2 diabetes development.

By balancing the meals and controlling portion sizes, moderate consulting of high-GI foods can be included in your dietary routine. Combining high-GI foods with protein, fat, or fiber may slow digestion and the release of glucose into the bloodstream. Eating plain white bread may cause your blood sugar to spike, but adding slices of chicken, lettuce, tomatoes, and hummus to the bread may lead to stable post-meal (postprandial) blood sugar levels.

1. High-sugar beverages

High-sugar beverages are a major source of added sugar in the diet, and excessive intake is linked to many health problems like obesity, type 2 diabetes, and cardiovascular disease. They’re also some of the worst foods for blood sugar.

Soda

Soda is a carbonated beverage high in added sugar and calories that offers no nutritional value. It also has a high glycemic index. Instead of sugary soda, a more mindful choice to consider would be seltzer water flavored with a spritz of lemon or lime.

Fruit juice

Fruit juice may have some nutritional value. For example, 100% orange juice provides vitamin C, potassium, and folate. But orange juice and other fruit juices digest quickly, causing a rapid rise in blood sugar levels.

To minimize blood sugar impact, drink 100% fruit juice with meals like hard-cooked eggs and 100% whole-wheat toast. However, people with diabetes should be mindful of the portion size of fruit juice, or consider diluting the juice with water or choosing unsweetened tea or water with berries instead.

Energy drinks

Many people reach for energy drinks when feeling sluggish. These drinks have a long list of ingredients that may include added sugar and caffeine. Like other high-sugar beverages, energy drinks may increase blood glucose levels. Energy drinks may also increase blood pressure and heart rate.

Unsweetened black coffee contains caffeine and other biologically active compounds associated with supporting overall health and makes a better choice than energy drinks. To reduce the risk of negative side effects of caffeine, you should limit your daily intake to no more than 400 milligrams.

2. Refined carbohydrates

Refined carbohydrates, also called refined grains, are whole grains processed to remove the germ and bran to improve texture, cooking properties, and shelf-life. However, the processing also removes the fiber and many of the micronutrients.

Anything made from white flour, white bread, pasta, and pastries contains refined carbohydrates. In addition to lacking whole grain macronutrients and micronutrients, processed grains cause fluctuations in insulin and blood glucose levels, along with post-meal hypoglycemia — when blood sugar levels drop too low a few hours after you eat.

White bread

White bread has a glycemic index of 100. Swapping out your white bread for 100% whole-grain bread may improve your nutritional intake, but whole-wheat bread also has a high glycemic index of 74.

Reduce the effects on blood sugar by adding healthy proteins, fats, and fiber to whole-grain bread, like peanut butter and blueberries or tuna with diced red onions, green apples, and walnuts.

Pasta

A randomized controlled trial published in the Journal of Nutrition in 2022 found that pasta may not have as much of an impact on blood sugar levels as white bread or refined cereal. Pasta’s starch and protein structure slows the digestive process. Cooking your pasta al dente also lessens its effect on blood sugar. However, glucose sensitivity to certain products, such as pasta, can vary. Regular pasta is made from refined grains, and people with diabetes may want to consider wheat pasta alternatives like legume-based pasta or vegetable pasta.

Pastries and cake

Pastries and cakes are high in added sugar, refined flour, unhealthy fat, and sodium. You don’t need to give up sweets, but you should try to keep portions small or make healthier dessert choices.

White rice

Rice is a staple food in many cultures, but it’s a high-glycemic food. Parboiled whole grain (brown rice) rice that’s chewier digests slower and may not have as much of an impact on blood sugar. You can also combine your rice with other healthy foods like fish and vegetables.

Cereals

It’s not only the sugary breakfast cereals that raise blood sugar. Instant oatmeal and bran flakes are also fast-digesting cereals that cause spikes in blood sugar.

Use the food label to find healthier options. Look for cereals that list whole grains as the first ingredient, limit added sugar, and provide at least four grams of fiber per serving.

3. Processed snacks

Processed snacks are manufactured products that contain multiple ingredients along with additives to improve taste, texture, appearance, and shelf-life. While they’re made from a variety of ingredients, processed foods may lack micronutrients present in whole foods.

Chips

Chips are crunchy and salty and satisfy many cravings. But they’re also high in sodium, fat, and refined carbohydrates. Instead of chips, snack on 100% whole-grain crackers with cheese or nut butter.

Pretzels

Pretzels are viewed as a healthier snack because they’re baked, not fried. But these salty snacks are made with refined flour and cause a rapid spike and drop in blood sugar.

Lessen the effects of your pretzels by eating them with other foods like hummus and carrot sticks or Greek yogurt and strawberries. People with diabetes may want to avoid refined grain snack foods like pretzels and instead choose other on-the-go options that have less of an effect on blood sugar levels, like nuts and berries or carrot sticks and cheese.

Energy bars

Energy bars look like healthy foods. They have protein and carbs, but some bars can have more than 20 grams of sugar. If you need a boost and like the convenience of energy bars, look for brands that have healthy carb sources like whole grains and less added sugar.

4. Deep-fried foods

Deep-fried foods have a mass appeal. But the cooking method is very unhealthy, adding extra calories and fat. Deep-fried foods also disrupt glycemic control and may indirectly increase the risk of type 2 diabetes.

French fries

Eating french fries may increase the risk of type 2 diabetes, according to a 2018 meta-analysis published in the Iranian Journal of Public Health. Potatoes are a high glycemic food and digest quickly, causing a rapid rise in blood sugar. Further, deep-fried french fries are a source of unhealthy fat, contributing to other health risks like cardiovascular disease.

Instead of french fries, try roasted potatoes and eat them with roasted chicken and vegetables to balance out the carbs.

Donuts

Donuts are similar to pastries and cakes. They are made with refined flour and sugar and are high in sodium. But frying increases fat and calories. For people with diabetes, a mindful approach when craving sweets could be homemade energy balls, chia pudding, or yogurt with berries.

5. Brown and white sugar

Brown and white sugar are added sugars. They pack in calories without offering any nutritive value. They’re also fast-digesting carbohydrates and increase blood sugar levels. According to dietary recommendations, it's suggested to limit calories from added sugars to 10% or less.

Added sugars aren’t the same as naturally occurring sugars. The naturally-occurring sugars commonly found in foods like fruits and milk come with beneficial nutrients like fiber, vitamins, and minerals.

Sugar substitutes are an alternative to brown and white sugar, adding sweetness without affecting blood sugar or adding calories. Though generally recognized as safe, the World Health Organization warns not to rely on nonnutritive sweeteners as a tool to help with weight control. However, to control blood sugar levels, sugar substitutes such as erythritol or stevia can occasionally be included in the dietary routine.

What you eat affects blood sugar levels. If you have diabetes, monitoring carbohydrate intake and blood sugar levels is an important part of your management plan. Avoiding or limiting foods that cause spikes in blood sugar levels can improve control.