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The Importance of Fiber in Diabetes Management

Mar 28, 2025

Fiber is a powerful nutrient. Why? Because fiber has the ability to provide benefits in many different chronic diseases such as digestive disorders, heart disease, and diabetes. But adding more fiber to your diet may be challenging, especially if you don’t know where to start. In this article, we will be focusing on how fueling up with fiber is great for diabetes and we’ll share some simple steps to get you started. Let’s learn more about fiber and diabetes!

What is Fiber?

Fiber is defined as the portion of plant foods that escapes digestion. This is different from other nutrients we eat, such as carbohydrates, proteins, and fats because our body does not break down fiber to use for energy. Rather, it passes through our system intact, bringing along with it many health benefits.

While there are many benefits to eating fiber, there are 3 main effects that are the most well-known:

  1. Reducing cholesterol.
  2. Lowering blood glucose levels.
  3. Maintaining a healthy bowel.

Fiber helps to lower cholesterol in two different ways. The first is through decreasing the absorption of cholesterol that we have eaten, and the second is through inhibiting our body from making more of its own cholesterol. Fiber also assists with maintaining bowel health. This occurs through the bulking action that fiber gives to stools as well as aiding in keeping us regular in our bowel movements. Lastly, fiber is beneficial for blood sugar. Fiber helps to decrease the glycemic index of foods as well as delay the absorption of sugar.

Types of Fiber

There are lots of different ways that fiber can be classified, but we are going to focus on solubility in the context of fiber and diabetes. Soluble fiber is found in foods that hold on to and absorb water. Because of this, they form a thick, gel-like substance as they travel through our digestive system. It is this type of fiber that helps to lower cholesterol and glucose levels, as well as help keep you full. Insoluble fiber does not have these characteristics and therefore passes through the GI tract more intact. Because of this, it helps to prevent and ease constipation and assist in colon health.

Fiber and Diabetes

Let’s come back to fiber and blood sugar. This is where it becomes an important player in diabetes management. As mentioned above, there are two ways in which fiber influences diabetes: the glycemic index and delaying the absorption of sugar. Let’s break this down further.

The glycemic index is a way to classify foods based on how they influence our blood sugar. Foods with a high glycemic index will cause our blood sugar to spike. Fruits, which can contain natural sugar, can cause your blood sugar to rise, but what makes them different from other foods with a high glycemic index is that they contain fiber. This lowers the effect that the food has on your blood sugar.

Not only does the fiber content help to pull down the glycemic index, but it also works to our benefit once we have consumed it. Soluble fiber specifically helps to slow down the digestion of sugars. This is because of soluble fiber’s ability to hold water and become gel-like. This slows down the digestion and absorption of the carbohydrates consumed. Are you beginning to see how fiber and diabetes are related?

Glycemic Index versus Glycemic Load

While the glycemic index is one way to categorize foods, it doesn’t give us a complete picture of what a particular food will do to our blood sugar. This is where the concept of glycemic load comes into play. Glycemic load takes into account the quality and quantity of carbohydrates in a normal serving of a food. Let’s use watermelon as an example. Watermelon has a glycemic index of 80. Theoretically, this means that it should spike our blood sugar. But when you eat a serving of watermelon, which is equal to 1 cup, not all the carbohydrates are actually available to be broken down into glucose due to the presence of fiber. This means it has a low glycemic load of 5. Therefore, glycemic load is a way to categorize foods based on the presence of fiber.

Fiber Favorites

Now that we have talked about all these amazing benefits of fiber, let’s talk about which foods to choose. All plant foods contain some amount of fiber, some will just have more than others. An important point here is the emphasis on plant foods. A common misconception is that meat contains fiber, but if we look at the definition of fiber again, it is the portion of plant foods that escapes digestion.

There are 4 main categories of foods that are full of fiber:

  • Beans & Legumes: Sources include chickpeas, black beans, pinto beans, lentils, peas, and soybeans. Eating 3 servings of this food group per day is a great start to adding in more fiber!
  • Whole Grains: Some options include quinoa, brown rice, popcorn, whole wheat, oats, etc. The less processed your whole grains, the better! Eating 3 servings of whole grains per day is the goal.
  • Fruits & Veggies: Bananas, berries, broccoli, spinach, sweet potatoes, the list could go on and on. The options here are endless!
  • Nuts & Seeds: Almonds, walnuts, pistachios, chia seeds, flaxseeds, sesame seeds, etc. 1 serving of nuts and seeds per day is the recommended intake. Great for a quick snack!

For even more ideas for fiber foods, check out this article from Mayo Clinic!

Action Steps

Here are a few takeaways that can help you incorporate more fiber into your diet:

  • How much fiber should you eat? Aim for 40 grams of total dietary fiber per day. This includes both soluble and insoluble fiber.
  • Find your favorites: Start by adding in plant foods that you already like to eat. This will make the process much more enjoyable!
  • Increase intake slowly: Increasing fiber consumption too fast can cause discomfort such as gas and bloating. Make sure to increase your intake slowly.
  • Drink water: Remember how soluble fiber holds on to water, slowing down the digestion of sugars? We need to make sure to give the fiber enough water to do its job properly. Aim to drink half of your body weight in ounces of water daily.

As you can see, fiber has many different health benefits and can be useful in managing several chronic diseases including diabetes. If you would like more information on the interactions of fiber and diabetes, or how to fuel with fiber, schedule an appointment with us today! For more tips on eating well check out our recipes at  https://lifestylemedical.com/resources/

References

Weickert, M. O., & Pfeiffer, A. (2018). Impact of Dietary Fiber Consumption on Insulin Resistance and the Prevention of Type 2 Diabetes. The Journal of nutrition, 148(1), 7–12. https://doi.org/10.1093/jn/nxx008