Whether you're keto, vegan, omnivore, or anything in between, one thing most health experts agree on is that we could all use more fiber in our diet. 

Fiber, also known as "roughage," offers a wide range of health benefits both directly and indirectly due to its activity in your digestive tract.

In this article, we'll explore what fiber is and how it can directly impact both weight loss and blood sugar management.

What Is Fiber?

Dietary fiber is the rough, indigestible part of plants and is technically a type of carbohydrate. We say "technically" because fiber isn't broken down and absorbed like other carbohydrates. In fact, fiber moves through your digestive system and is eliminated pretty much intact. 

Since fiber never makes it into circulation, its direct benefits all involve digestion and gut health. That said, the role that fiber plays in digestion is far-reaching, and studies show that getting enough fiber is crucial for weight maintenance, heart health, metabolic health, and potentially even cancer prevention[1]. 

While there are many different sources of fiber, there are two primary types; soluble and insoluble. Soluble fiber dissolves in water, creating a gel-like substance that helps your body clear excess cholesterol. This type of fiber also acts as fuel for your gut bacteria and is considered a prebiotic. 

Insoluble fiber, on the other hand, does not dissolve in water. Instead, it attracts water into your digestive system, helping to soften your stool. This allows for easier passage, making insoluble fiber ideal for anyone that struggles with constipation. 

How Does Fiber Assist With Blood Sugar Control?

Studies in people with type 2 diabetes show that increased dietary fiber intake can help to control blood sugar and reduce hyperinsulinemia[2].

But how exactly does fiber accomplish this? 

Fiber Directly Impacts Digestion 

Fiber can directly lower the glycemic response of foods in two ways:

  • #1. Since fiber can't be absorbed into your circulation, foods high in fiber will naturally produce a lower glycemic response as this nutrient can't make it into your blood. Therefore, only the non-fibrous carbohydrates in your food will contribute to a blood glucose response. 
  • #2. The fiber content of your food can influence the accessibility of nutrient breakdown by enzymes. In this way, fiber slows digestion as enzymes have to work harder to get to the fat, protein, and carbohydrates trapped within the food matrix. As digestion is slowed down, so too is the uptake of glucose into circulation[3]. 

Fiber Promotes the Production of SCFA 

SCFA (short-chain fatty acids) act as an energy source for your gut lining, fueling the cells responsible for absorption in your intestines. Studies show that a deficiency of SCFAs is associated with type 2 diabetes and that consuming a diet rich in fiber can promote the repopulation of SCFA-producing organisms. 

In one study, researchers found that increasing fiber intake in diabetic volunteers increased SCFA production and improved the entire gut microbiome. As a result, the volunteers saw a decline in hemoglobin A1c, improved blood glucose levels, and elevated levels of glucagon-like peptide-1, which is a regulator of the hormone insulin[4][5].

Fiber Feeds Beneficial Bacteria 

As a prebiotic, fiber acts as fuel for the beneficial bacteria in your gut and, therefore, can enhance microbial diversity. One of the known benefits of improved microbial health is a reduction in inflammation, which may directly impact metabolic processes related to blood glucose control and the progression of type 2 diabetes[6]. 

How Does Fiber Assist With Weight Loss?

In addition to blood glucose control, another way in which dietary fiber can enhance metabolic health is by supporting weight loss. 

Fiber Keep You Full Longer

Research shows that viscous fiber, or soluble fiber, can help to control appetite by enhancing feelings of satiety and therefore reducing overall food intake. By slowing down your digestive process, fiber helps you feel full longer, reducing your drive for food[7].

Fiber Reduces Hunger Hormones 

Interestingly, fibers' ability to keep you physically full is only part of their satiating effect. 

In addition to slowing digestion, fiber helps to regulate the hormone ghrelin, also known as the "hunger hormone." When ghrelin is released, it stimulates your appetite and sends a message to your brain that you need more food. By helping to control ghrelin, fiber reduces unnecessary urges for food[8]. 

Fiber Enhances Satiety Hormones

In addition to reducing levels of your hunger hormone, dietary fiber also promotes the signaling of your satiety hormone, leptin. 

Leptin is released from your fat cells and plays a crucial role in modulating energy balance and weight. It sends a signal to your brain when you have had enough to eat to diminish appetite and, therefore, can help to prevent overeating. 

Furthermore, studies show that including more fiber in your diet may improve a condition known as leptin resistance. Leptin resistance occurs when your brain no longer responds to leptin signals as it should, leaving you unsatisfied and continuously hungry. It's believed that leptin resistance may be one reason we see so many people struggling with obesity today[9].

Fiber Promotes Microbial Diversity In Favor Of Weight Loss

Although your gut microbiota lives in your gastrointestinal tract, they can exert metabolic effects systemically. In fact, we're constantly learning new ways in which a healthy microbiome can impact health.

As mentioned previously, one of the benefits of dietary fiber is that it acts as a prebiotic, feeding the healthy bacteria in your gut. In this way, fiber helps to promote microbial diversity. 

Studies show that the makeup of your gut microbiota is directly associated with body weight. When your diversity is low, it increases the risk of obesity, and when diversity is high, it reduces long-term weight gain[10]. 

Some research suggests that greater microbial diversity can enhance energy metabolism and therefore assist with weight loss and maintenance independently of calorie intake[11]. 

Low-Carb Sources Of Dietary Fiber

Fiber can be found in almost all plant-based foods, but not all foods that are rich in fiber are low-carb. If you do a google search for high-fiber foods, you'll likely see a lot of whole grains like brown rice, quinoa, and whole wheat or beans like lentils and chickpeas. While these foods offer a good source of fiber, their overall carbohydrate content won't work for most people trying to follow a keto or low-carb diet.

Below are some low-carb fiber-rich foods to start incorporating into your meal plan:

  • Seeds – flax seeds, chia seeds, pumpkin seeds
  • Avocado
  • Coconut (unsweetened)
  • Berries – raspberries, blackberries
  • Nuts – pistachios, almonds, 
  • Vegetables – broccoli, asparagus, cabbage, spinach, collard greens, okra, artichoke, brussels sprouts 


In addition to supporting weight management and blood sugar control, consuming a high-fiber diet offers several other health benefits for overall wellness. For example, fiber is well-known to support the health of your digestive tract, and its primary claim to fame is in the prevention of heart disease due to its role in reducing blood pressure and cholesterol levels.

If you already have insulin resistance, diabetes, or prediabetes, adding more fiber to your diet is an excellent way to enhance your metabolic health.

To learn more about what foods can support your health and healing journey, take a look at the BioCoach App for more tips and guidance.


  2. Chandalia, Manisha, et al. "Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus." New England Journal of Medicine 342.19 (2000): 1392-1398.
  3. Riccardi, Gabriele, and Angela A. Rivellese. "Effects of dietary fiber and carbohydrate on glucose and lipoprotein metabolism in diabetic patients." Diabetes care 14.12 (1991): 1115-1125.
  4. Zhao, Liping, et al. "Gut bacteria selectively promoted by dietary fibers alleviate type 2 diabetes." Science 359.6380 (2018): 1151-1156.
  5. Lim, Gareth E., and Patricia L. Brubaker. "Glucagon-like peptide 1 secretion by the L-cell: the view from within." Diabetes 55.Supplement_2 (2006): S70-S77.
  6. Wagenaar, Carlijn A., et al. "The effect of dietary interventions on chronic inflammatory diseases in relation to the microbiome: a systematic review." Nutrients 13.9 (2021): 3208.
  7. Ho, Irene HH, Lara Matia-Merino, and Lee M. Huffman. "Use of viscous fibres in beverages for appetite control: a review of studies." International Journal of Food Sciences and Nutrition 66.5 (2015): 479-490.
  8. St-Pierre, David H., et al. "Fiber intake predicts ghrelin levels in overweight and obese postmenopausal women." European journal of endocrinology 161.1 (2009): 65-72.
  9. Zhang, Ru, et al. "Effects of cereal fiber on leptin resistance and sensitivity in C57BL/6J mice fed a high-fat/cholesterol diet." Food & nutrition research 60.1 (2016): 31690.
  10. Cronin, Peter, et al. "Dietary fibre modulates the gut microbiota." Nutrients 13.5 (2021): 1655.
  11. Menni, Cristina, et al. "Gut microbiome diversity and high-fibre intake are related to lower long-term weight gain." International journal of obesity 41.7 (2017): 1099-1105.

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