What are the worst carbohydrates for type 2 diabetes? A Guide to Unhealthy Choices

November 2, 2025 •

3 min read

An estimated 9.8% of new type 2 diabetes cases in 2020 were linked to sugary beverages, highlighting the impact of poor carbohydrate choices. Understanding what are the worst carbohydrates for type 2 diabetes is crucial for managing blood glucose and preventing long-term health complications.

Quick Summary

Certain carbohydrates, particularly refined grains, sugary drinks, and ultra-processed foods, cause rapid blood sugar spikes and should be limited or avoided by people with type 2 diabetes.

Key Points

Avoid Sugary Drinks: Liquid sugars from soda, juice, and energy drinks are rapidly absorbed, causing significant and dangerous blood sugar spikes.
Limit Refined Grains: Foods made with white flour and white rice lack fiber and raise blood glucose levels quickly, unlike their whole-grain counterparts.
Minimize Ultra-Processed and Fried Foods: Packaged snacks, baked goods, fast food, and fried starches contribute to weight gain and worsen insulin resistance.
Read Labels Carefully: Check for added sugars (like corn syrup or dextrose) and prioritize high-fiber options to better manage blood sugar.
Prioritize Complex Carbs with Fiber: Opt for nutrient-dense whole grains, vegetables, and legumes to ensure a slower, more gradual release of sugar into the bloodstream.
Understand the Glycemic Index: Foods with a high GI, like many refined carbs, cause faster blood sugar rises compared to lower GI foods.

Understanding Carbohydrates and Blood Sugar

For individuals with type 2 diabetes, managing carbohydrate intake is essential for stable blood sugar levels. When carbs are consumed, they are converted to glucose, which enters the bloodstream. In type 2 diabetes, insulin's ability to process this glucose is impaired, leading to high blood sugar (hyperglycemia). Different types of carbohydrates affect blood sugar differently. Generally, highly processed carbs low in fiber and high in added sugars are the worst, causing rapid and significant blood glucose spikes.

The Worst Offenders: A Breakdown of Bad Carbs

Sugary Beverages

Sugary drinks are considered among the worst carbohydrate sources for those with type 2 diabetes because the liquid sugar is quickly absorbed, leading to sudden and significant blood glucose increases. This includes sodas, sweetened teas, fruit juices (even 100%), and energy drinks, all of which contain free sugars and offer little nutritional value while negatively impacting blood sugar control.

Refined Grains

Refined grains are starches where the fiber-rich bran and germ are removed, leaving only the rapidly digestible starchy endosperm. This process removes vital nutrients and fiber. Examples include white bread, white flour products like bagels and tortillas, white rice, white pasta, and many sugary breakfast cereals. These cause quick blood sugar spikes due to their lack of fiber.

Ultra-Processed and Packaged Foods

Ultra-processed foods have been linked to an increased risk of type 2 diabetes. These foods are typically low in fiber and nutrients but high in calories, unhealthy fats, and added sugars. Common examples are chips, crackers, pretzels, baked goods, desserts, candy, and many fast food or ready meals. These items often contain refined flour and have a high glycemic index, contributing to blood sugar issues and potential weight gain.

Understanding the Glycemic Impact

The glycemic index (GI) helps determine how quickly different carbohydrates raise blood sugar, ranking foods on a scale of 0 to 100. High-GI foods, typical of the worst carbohydrates, cause rapid blood glucose increases. While useful, GI should be considered along with portion size and overall nutritional value.

Good Carbs vs. Worst Carbs: A Comparison Table


Feature	Good Carbohydrates	Worst Carbohydrates
Processing Level	Unprocessed or minimally processed	Highly refined and ultra-processed
Fiber Content	High (e.g., whole grains, legumes)	Low or stripped away (e.g., white flour)
Sugar Content	Naturally occurring sugars (fruit)	Added sugars and high-fructose corn syrup
Blood Sugar Impact	Gradual rise (low GI)	Rapid spike (high GI)
Nutritional Value	Rich in vitamins, minerals, and antioxidants	Often considered 'empty calories'
Feeling of Fullness	High fiber promotes satiety	Can contribute to overconsumption
Examples	Quinoa, oatmeal, beans, berries	White bread, soda, candy, chips

How to Swap Bad Carbs for Good Carbs

Making smart substitutions is key to managing carbohydrate intake with type 2 diabetes. Replace sugary drinks with water or unsweetened options. Choose whole grain bread with at least 3g of fiber per slice, brown rice, quinoa, and whole wheat pasta over refined grains. Opt for nutritious snacks like nuts, seeds, or berries instead of processed options. Cooking at home helps control ingredients and avoid hidden sugars and starches. When checking nutrition labels, prioritize higher fiber content to help slow glucose absorption.

Conclusion: Making Informed Choices

For individuals with type 2 diabetes, a healthy diet is a powerful tool for managing blood sugar and overall health. Understanding and limiting the worst carbohydrates, such as sugary drinks, refined grains, and ultra-processed foods, is critical. By prioritizing high-fiber, minimally processed options, you can help stabilize blood glucose levels and reduce the risk of complications. Consulting a healthcare professional or registered dietitian is recommended for a personalized nutrition plan. For more guidance on healthy eating with diabetes, visit the American Diabetes Association website.

Frequently Asked Questions

A carbohydrate is considered 'bad' if it is highly refined, has a high glycemic index, and contains added sugars or unhealthy fats. These characteristics cause rapid spikes in blood sugar levels after eating.

No, completely avoiding carbohydrates is not necessary or recommended. The key is to choose the right types of carbohydrates, such as complex carbs rich in fiber, and manage portion sizes to maintain stable blood sugar levels.

Foods with added sugars are particularly bad for blood sugar control and should be limited. Foods with naturally occurring sugars, like fresh whole fruits and dairy, are generally healthier because they also contain beneficial nutrients and fiber that slow sugar absorption.

The glycemic index ranks foods on how quickly they raise blood sugar. For managing type 2 diabetes, it is important to choose lower GI foods, as they cause a slower and more gradual rise in blood glucose.

Check the ingredient list for refined flour (e.g., 'enriched wheat flour') and added sweeteners like corn syrup, dextrose, or sucrose. Also, check the fiber content; higher fiber is better for blood sugar control.

Healthy carb sources include unprocessed, non-starchy vegetables (like broccoli and spinach), whole grains (oatmeal, brown rice), legumes (beans, lentils), and whole fruits.

Yes, even 100% fruit juice is a poor choice for diabetes management. It lacks the fiber of whole fruit, and the concentrated liquid sugar is absorbed quickly, causing a significant blood sugar spike.