Carbohydrates, Sugar, Fiber, and Chronic Disease
Carbohydrates, Sugar, Fiber, and Chronic Disease
Carbohydrates have been blamed for just about everything over the last few decades. Weight gain. Diabetes. Heart disease. Even cancer. As a result, entire food groups have been pushed aside, while fear-based nutrition messaging continues to thrive.
This is one of a series of posts covering foundational information on carbohydrates, pulling together what we know about carbohydrates, sugar, and fiber in the context of chronic disease. That includes diabetes, heart disease, and certain cancers. But it must be said that all these chronic diseases are multifactorial and complex, and suggesting, or assigning “blame” to the individual for not doing things “right,” is not helpful and is often untrue anyway. The goal here is not to oversimplify complex conditions but to separate myths from evidence and to focus on patterns, not individual foods.
Diabetes and Carbohydrates: Myths vs Reality
When people talk about carbohydrates and chronic disease, type 2 diabetes is usually the first condition mentioned. Type 2 diabetes is characterized by insulin resistance and impaired glucose regulation. While lifestyle factors can influence risk, diabetes is not caused by a single food or nutrient.
Common modifiable risk factors for type 2 diabetes can include:
Body weight and fat distribution
Physical inactivity
Sleep quality
Chronic stress
Overall dietary patterns
Genetics and family history also play a role; however, obviously, we can’t change that. But we can combat it with those modifiable risk factors.
It is important to say this clearly: the presence of modifiable risk factors does not mean someone caused their diabetes. Biology, genetics, access to care, and social factors all matter.
Myth: Sugar Causes Diabetes
Sugar does not directly cause diabetes. High intakes of added sugars can contribute to excess calorie intake and weight gain over time, which may increase risk, but eating sugar does not automatically lead to diabetes.
Myth: People With Diabetes Cannot Eat Sugar
People with diabetes can eat sugar. Carbohydrates are part of diabetes management, not something that must be eliminated. What matters is the amount, timing, type of carbohydrate, and how it fits into the overall eating pattern, including what other foods are consumed with the carbohydrates.
Myth: All Carbohydrates Raise Blood Sugar the Same Way
Carbohydrates are not interchangeable. Fiber content, food structure, fat-protein pairing, and portion size all influence the blood glucose response.
How Carbohydrates Fit In
Carbohydrates are the body’s primary energy source. For people with diabetes or those trying to manage their blood sugar, learning to distribute carbohydrates across meals and to choose a mix of fiber-rich and refined sources is part of effective management.
Read More: Carbohydrates vs Sugar: What’s the Difference and Why It Matters
How Carbohydrates Can Help
Fiber plays a major role. Soluble fiber can slow digestion and help blunt post-meal glucose rises. Diets higher in fiber from whole grains, beans, fruits, and vegetables are consistently associated with better glycemic control and reduced diabetes risk
Read More: Fiber 101: Soluble, Insoluble, Functional Fiber, and Resistant Starch
Heart Disease and Carbohydrates
Heart disease is an umbrella term that includes coronary artery disease, heart attacks, and other cardiovascular conditions. It is influenced by a wide range of factors, including genetics, blood lipids, blood pressure, smoking, physical activity, and diet.
It is also worth stating the obvious. Heart disease can happen to anyone with a heart. There is no single “look” that predicts a heart attack. People who are very fit and exercise regularly can have heart disease – I’ve seen it happen plenty.
Where Carbohydrates Get Blamed
Carbohydrates are often blamed for heart disease because of associations with high sugar intake. The issue is not carbohydrates themselves but dietary patterns that are high in added sugars and low in nutrient density.
Foods high in added sugars are often low in fiber, vitamins, and minerals. When these foods crowd out fruits, vegetables, whole grains, and legumes, overall diet quality suffers.
What Actually Matters More
Fat quality remains a major contributor to cardiovascular risk. Diets high in saturated fats and trans fats are associated with increased risk, while unsaturated fats from foods like nuts, seeds, and olive oil are protective. The science is clear on this. It is not ambiguous.
How Carbohydrates Fit In
Whole food carbohydrate sources can support heart health. Whole grains, beans, fruits, and vegetables provide fiber, antioxidants, and phytonutrients that support cholesterol management and vascular health.
How Carbohydrates Can Help
Soluble fiber can help lower LDL cholesterol. Potassium-rich carbohydrate foods, such as fruits and vegetables, help regulate blood pressure. These benefits are lost when carbohydrates are overly restricted (or overly processed and stripped of those nutrients like potassium).
Cancer, Fiber, and Dietary Patterns
Cancer is not a single disease, and diet-related risk varies by cancer type. Some cancers, particularly colorectal cancer, have clearer associations with dietary patterns.
There is no strong evidence that sugar directly feeds cancer in the way it is often portrayed. All cells use glucose. The concern is not sugar itself but the dietary context.
Read More: What Are Carbohydrates? Fiber, Starch, and Sugar Explained
What The Evidence Suggests
Low fiber intake is consistently associated with increased risk of colorectal cancer. Diets low in fruits, vegetables, whole grains, and legumes lack protective compounds that support gut health and regular bowel function.
High intakes of ultra-processed foods that are low in fiber and high in added sugars may indirectly increase cancer risk by displacing protective foods and contributing to inflammation and metabolic dysfunction.
Context Matters
A meal or snack like cake and ice cream at a birthday party is not the problem. Chronic disease risk is shaped by what the overall diet lacks over time, not by occasional celebrations. Having cake and ice cream, or whatever, is not solely in and of itself increasing the risk for diabetes, heart disease, and colorectal cancer. It’s the lack of whole grains, fruits, vegetables, and beans that is the bigger issue if people “fear” or eliminate carbs under the guise of being unhealthy.
The Bigger Picture
Carbohydrates are not the villain they are often made out to be. Problems arise when carbohydrates are stripped of fiber, nutrients, and structure, then consumed in excess, while more protective foods are missing.
Fear-based messaging around sugar and carbohydrates tends to push people toward restriction rather than improvement. That approach often backfires and distracts from what actually supports long-term health.
It’s less about what people ARE eating and more about what they ARE NOT eating.
Bottom Line
Carbohydrates play a role in chronic disease risk, but not in the simplistic ways they are often portrayed. Sugar does not cause diabetes. People with diabetes can eat carbohydrates. Heart disease is not prevented by cutting carbs alone. Cancer risk is more closely tied to what is missing from the diet than to sugar itself.
Fiber-rich carbohydrate foods support metabolic, heart, and gut health. The goal is not elimination but balance and quality within the context of the overall diet.
The next post in this series will focus on real world application: How to Build a Balanced Plate When Carbohydrates Are Involved.
Related blogs in this series:
Carbohydrates vs Sugar: What’s the Difference and Why It Matters
The Six Essential Nutrients Explained: A Foundational Guide to Nutrition
What Are Carbohydrates? Fiber, Starch, and Sugar Explained
Fiber 101: Soluble, Insoluble, Functional Fiber, and Resistant Starch
What Are Net Carbs and Do They Actually Matter?
What Are the Names of Added Sugars?
“Detoxing” From Sugar and the Idea of Sugar Addiction
Low-Carb and No-Carb Diets: What They Get Right and What They Miss
Healthier Alternative Sugars: What the Science Actually Says
