by Katlyn Adams, MS, ISSA

“Why should I be eating carbohydrates…if any at all?”

This post starts the beginning of a series all about why you should be eating carbohydrates. 

In recent years, there has been a dark light shed on carbohydrates due to a great deal of misinformation. I would argue that carbohydrates are unfairly getting a bad rap!  They deserve way more explanation than to simply believe they cause weight gain. 

Holly has tasked me with the question “Why eat carbohydrates?” assuming that you hesitate when you reach for a piece of bread.

Why should you eat the bread, the apple, the zucchini, and more?  The answer is…fiber. 

Hello! I’m Katlyn Adams and I’m teaming up with Holly to bring you researched-supported information from the nutrition field.

I have a Bachelor’s degree in Biochemistry, hold a Nutrition Coach certification through ISSA, and I’m currently enrolled in a Master’s program for Dietetics and Nutrition.  I am excited to guide you through some of the insights I have pertaining to nutrition in order to help you achieve optimal health. 

Let’s begin by talking about fiber.  The definition of fiber simply states that it’s the parts of a plant that are unable to be digested by enzymes in your body, and are therefore fermented in the large intestine.

So why is something that is indigestible important to eat? Shouldn’t indigestible material be avoided? Nope!

Although fiber may be indigestible that is exactly what makes it so powerful for your body.

Fiber can be broken down into soluble and insoluble pieces.  Soluble fiber is able to be dissolved in water and can be very easily fermented by the gut microflora, the helpful bacteria in your gut.  Whereas insoluble fiber cannot be dissolved and makes up the bulk of your stool. Insoluble fiber can also work to inhibit absorption and digestion throughout the large intestine. 

All fiber is also accompanied by vitamins, minerals, phytochemicals, and even antioxidants that also improve health on another level. 

Not only is fiber good for you in general, but it also brings several other health benefits that promote optimal vitality . 

But there’s a catch….The only way to get fiber is to eat carbs!

Yep, you read that correctly. Carbohydrates are our only source of fiber.

Carbohydrates = Fiber. 

“Fiber” is an umbrella term as there are many different kinds of fiber, each of which has unique functions for your health. 

 Some of functions of fiber are…

• beneficial fermentation in the large intestine

• increased intestinal viscosity

• nutrient absorption

• gut hormone production

• short chain fatty acid production

All of these functions can help to prevent and control conditions such as type 2 diabetes, cancer, cardiovascular disease, obesity, and gut health. 

Tip: Not all fiber is created equally

Read on below and I’ll break down everything you need to know about fiber.

In case you missed it above, this is the first in a series about carbohydrates, and why you need to be eating them if you want to be truly healthy.

Stay tuned in the coming weeks for Part 2 on brain health, and Part 3 on energy.

Let’s jump in deeper. As you’ll see in a just a few minutes, fiber is super important to prevent or manage some of the most common diseases today.

Type 2 Diabetes

Insulin resistance coincides with type 2 diabetes. 

Insulin resistance is when insulin receptors stop responding to insulin in the blood. Under normal circumstances when insulin is present in the blood it binds to receptors and brings blood glucose circulating into cells. 

But when there are large amounts of glucose in the blood all the time, insulin is also released in large amount and the insulin receptors become less sensitive to insulin resulting in less binding and more concentrated blood glucose.

High blood glucose for long periods of time can cause significant damage to blood vessels leading to other issues.

Fiber comes to the rescue by slowing the absorption of glucose into the blood. 

This alleviates the insulin receptors so they are not inundated, and gives them an opportunity to manage blood glucose levels at a better pace, as well as protects blood vessels from excessive amounts of glucose in circulation. 

In a preventative manner, fiber lowers the amount of glucose in the bloodstream at any given time. It decreases the insulin that is released, which will decrease the likelihood of insulin resistance. 

Fiber will not only help manage glucose absorption when dealing with type 2 diabetes, it will also help to prevent the development of insulin resistance before type 2 diabetes.

Obesity

Fiber can curb obesity because it will keep you fuller for longer, prolonging the “effects” from each meal. 

Fiber increases the bulk in your digestive system allowing you to feel fuller and keep you from overeating. 

Coinciding with this, the slower absorption of nutrients gives the body the ability to use the energy as it comes in, rather than finding a way to store it as fat. 

Cancer

When fiber is fermented in the large intestine, short chain fatty acids are created. These components actually aid as cancer fighters.  They’re able to slow tumor growth and encourage intestinal cell death. This controls the opportunity cells have to malfunction. 

Fiber will also increase stool’s bulk and viscosity. This phenomenon decreases interactions between potential cancer-causing carcinogens and the cells that line the gut. 

With fiber comes antioxidants, which are known to be cancer preventative and increase bile acids in the gut which bind to carcinogens, eliminating or negating their effects on the body.

Cardiovascular Disease

As discussed previously, fibers increase short chain fatty acids which have anti-carcinogenic effects, and decrease serum cholesterol levels.

As you know, high cholesterol levels are often a predictor of heart disease risk. 

As mentioned in the diabetes section, fiber decreases the glucose absorption rate. This leads to better arterial wall health, and a decrease in plaque buildup on the arterial walls.

This also decreases the inflammation flags in the body, lowering plaque buildup and stubbornness.  This leads to healthier and clearer arteries and a decreased risk of developing cardiovascular disease!

Gut Health

The microbiota of the gut is highly important to our health, as you have probably heard about in the media.

The bacteria in the gut has the preventative effect for many inflammatory conditions such as IBS and autoimmune diseases. Because of short chain fatty acid production, the bacteria also reduces the risk of various cancers.

One of the issues with the Western Diet is that it generally lacks fiber which is seen to leave the gut with minimal diversity and low function. 

The fiber in our diet can introduce new beneficial bacteria populations to our systems. It also serves as an energy source for the bacteria as they use it regularly in fermentation.

The bacteria populations are not only diversified by fiber, but they also have protective effects on the gut lining, giving rise to important metabolic products that will benefit the body in fighting and preventing a plethora of different conditions. 

Without fiber, microbiome populations tend to shift their consumption patterns to less favorable metabolites. This can lead to irritation or proliferation of diseases and inflammation conditions. 

When fiber is lacking, the microbiome bacteria don’t ingest what they prefer, and they also do not stimulate the gut lining to secrete mucous like they should when they get enough fiber. This lack of fiber minimizes the mucosal membrane which ultimately is what protects the gut mucous cells from the outside environment that we ingest. 

Low fiber intake not only wreaks havoc on gut health but it also causes problems elsewhere in the body.  Low fiber intake can lead to obvious decreases in gut health, as well as lung conditions and decreased immune function. This is all thanks to the decrease in short chain fatty acids which would be the product of gut fermentation. 

You may have known that fiber is super beneficial for gut health. What’s surprising is that fiber is also crucial for optimal health in ways completely unrelated to the intestinal tract!

Supplementation

Now that I’ve given you compelling reasons to monitor your dietary fiber intake, let us talk about why supplementation may not be the best option when you need more.

Your first thought may be to go to supplementation because it’s often easier than finding good sources of fiber from food. 

However, I would proceed with caution here.  Supplementation may be beneficial in some cases, however I would argue that it’s often not the best approach here.

The fiber supplements are often riddled with ingredients other than fiber. 

They often have too much sugar and chemicals you’re unaware of. 

Supplementation can help with fiber intake but it may decrease the effectiveness by negatively affecting the body in other ways. Sadly, the supplementation industry is not highly regulated, and you may not have the time or interest in researching your best options.

It’s so easy to innocently fall into the trap of overusing fiber supplements. The problems is that it can lead to dependency, as well as stomach pain, gas, and even reflux. 

Another downside to supplementation is the lack of variety they provide.  Supplementation is unable to provide the variety of fiber content that whole foods are going to give you. 

Fiber has so many divisions and subdivisions, and finding a supplement that’s better than what whole foods provide is nearly impossible. I’m referring to the combo of not only insoluble and soluble but also all the subdivisions of fiber like inulin, arabinoxylan, beta-glucan, pectin, bran, cellulose, and more. 

Subdivisions of Fiber and Food Sources

Fiber is highly beneficial in many ways, as I have mentioned above.

Below I'll review where you can find the different fiber types in your favorite foods.

Arabinoxylan is a component of fiber found in whole grains, specifically in the bran and endosperm of the grain which are the outer two layers – often times lost in processing. 

The arabinoxylan component has been seen to be helpful in postprandial (after lunch or dinner) blood glucose and insulin levels. 

Inulin is completely metabolized by the microflora of the gut and ferments the byproduct, propionate.  This product will decrease the acetic acid to propionate ratio leading to decreased serum cholesterol and LDL levels.  Inulin can also be considered a prebiotic because it is known to introduce beneficial bacteria populations into the gut microbiome.  Studies show it can increase the absorption of certain minerals such as calcium, which is often deficient in your diet. Inulin can be found in foods such as onions, garlic, wheat, artichokes, and bananas.

Beta-glucan is found in the endosperm of grains and cereals, with barley and oats being the richest.  Beta-glucan has been shown to be beneficial in lipid and glucose metabolism.  As beta-glucan levels increase, serum cholesterol decreases, while also increasing short chain fatty acids.  However, due to beta-glucans structure, it’s sensitive to processing.  All of its benefits come from the way it’s processed because the beta bonds that make up the fiber component are sensitive (and this is where the benefits come from). Oats seem to be better at retaining benefits than barley, but a lot of factors ride on where it comes from and how it is processed. 

Pectin is present in citrus fruit, especially concentrated in the peels.  It is known for its formation of a gel like substance, which decreases intestinal inflammation and pathogenic bacteria.  It has even been found to bind to tumors limiting their growth as well as decrease migration risk. 

Bran is the outermost layer of a grain and it can control the postprandial glucose levels limiting risk for arterial wall destruction.  It can control serum cholesterol, triglycerides, and LDL levels, all leading to a decrease in cardiovascular disease risk.  It can also lead to an increase in satiety which generally helps control body mass by decreasing the likelihood of overeating. 

Cellulose is unique in that it is both soluble and insoluble lending itself to twofold benefits.  However, the bond structure is delicate so sometimes during processing the bonds responsible for insolubility become lost.  When fermented, cellulose creates short chain fatty acids, and also decreases blood glucose after a meal.

Although there are even more divisions of fiber, you can see that the benefits seem never ending.

To reiterate, the only way to get fiber is to consume carbohydrates. 

Your fear of carbohydrates could be hurting your fiber intake dramatically!  So, consider viewing carbohydrates as your “fiber friends” rather than something that causes weight gain. It’s already been proven that there is no direct correlation between carb intake and body fat percentages.

Are you ready to reach for a fiber-rich snack? I thought so!

Some of the best “fiber friends” include…

There are plenty more fiber rich foods, but it’s key to remember that carbohydrates are the only place you will be able to find fiber.

Hopefully you see the importance of carbohydrates in your diet and how fiber intake depends on that.

There's no question that fiber is required for optimal health. And that means that carbohydrates are essential.

So, go break some bread (whole wheat of course) and feel happy that you are providing your body with a powerful tool for health.

Catch me next time where I tackle carbohydrates from a different perspective. We’ll be talking about carbs and brain health. 

Happy Fueling! 
Katlyn

RESEARCH REFERENCES

Effects of Dietary Fiber and Its Components on Metabolic Health
Department of Human Nutrition, Kansas State University - James M. Lattimer and Mark D. Haub
Effects of Dietary Fiber and Its Components on Metabolic Health - PMC (nih.gov)

The Impact of Dietary Fiber on Gut Microbiota in Host Health and Disease
Cell Host and Microbe Vol. 23 – Kassem Makki, Edward C. Deehan, Jens Walter, and Fredrik Backhed
The Impact of Dietary Fiber on Gut Microbiota in Host Health and Disease - ScienceDirect