I have to admit—before I took medical nutrition classes in medical school, fiber didn’t seem that interesting to me. I thought I knew everything about it. You take it when you need to go to the bathroom, and that’s it. Right? 

Wrong. Fast forward a few years of nutrition education later and I am a huge proponent of increased fiber in western diets. Why? 

Because fiber is a safe, inexpensive food-as-medicine that has a host of benefits for your entire body, not just your digestive tract. Not all fiber is created equal, either, so science really does matter when it comes to using fiber for your health. Here’s the truth. 

‌‌‌‌Fiber’s Impact on Health

Fiber can help with health conditions like allergies, heavy metal toxicity, cognitive function, asthma, skin rashes, inflammatory bowel diseases, osteoporosis, and more. There’s even evidence that it prolongs life.

Yes, you read that right. Regularly consuming fiber could help you live longer!

If there were a drug that did all of the things that fiber does, I’m convinced it would be a million dollars a dose. If you account for the fact that fiber also has very few side effects, we’re looking at an incredibly effective, safe, and valuable health intervention that far outpaces any pill we’ve got.

Because those fruits and veggies are right in our grocery store, though, we often overlook them or take them for granted as medicine. For the sake of your skin, gut, and lifespan, you really should give fiber a shot. 

In this article, I’ll explain what fiber is, the many forms it comes in, and how to use it effectively and strategically for particular health benefits. Let’s dive in.

‌‌‌‌What Is Fiber?

Fibers are starches that the human digestive tract isn’t able to completely break down into sugar. Fibers are a type of carbohydrate; they only come from plant and grain foods like vegetables, tubers, grains, legumes, nuts, and seeds. 

You can’t find fibers in meats, eggs, cheeses, or oils. So, when we’re talking fiber, we’re talking plants.

‌‌‌‌Why You Must Consume Fiber With Water

Many people are familiar with the fiber + water equation when it comes to moving things through the digestive tract, but in case you are not, allow me to clarify. Fiber only works to regulate stool when it’s consumed with water.

This important fact is why fiber powders always come with instructions to take with a large glass of fluid. What happens if you take fiber on its own without water? It can actually make you constipated—the opposite of what you were probably hoping for!

This is because, in the digestive system, fiber and water create an increase in osmotic pressure that pulls more fluid across colonic membranes. This stimulates peristalsis—movement in the intestines. Without water, fiber just creates more bulk that has nowhere to go. It sits, and you aren’t able to push fecal matter through the digestive tract efficiently.

What does this mean for you? Just that, whenever you take a fiber supplement, you should always take it with water or as directed on the container. That way, it will work just like you want it to.

There are a few other ways to maximize and biohack your fiber consumption, as well.

‌‌‌‌Sources Of Fiber

Fruits and Vegetables

The great part about eating fresh fruits and vegetables as your fiber source is that they come prepackaged with their own ideal fiber-to-water ratio, so you don’t have to worry as much about water. This is even true if you’re eating semi-dried fruit like prunes.

Fiber-containing foods usually taste delicious and they have a host of other beneficial ingredients that help boost human health. Eating a black bean avocado brownie made with gluten-free flour is way more fun than taking a fiber pill for many folks.

Luckily, both are great options for getting your fiber numbers up.

Nuts and Seeds

Another awesome option for adding more fiber is to add more nuts and seeds to your normal recipes or as a healthy snack throughout the day.

I frequently advise my patients to add flaxseed and chia seeds to things like oatmeal, baking mix, and even savory dishes like chilis and soups. The bonus with these fiber-boosting seeds is that they also contain omega 3 fatty acids, which are essential for human health. 

Fiber Supplements

Lastly, if you don’t like or can’t eat enough fruits, veggies, nuts, or seeds, you can take a fiber supplement each day to make sure you’re hitting the goal of 25 grams per day set by the American Heart Association. Again, make sure to take it with plenty of water.

‌‌‌‌Fiber Can Help You Detoxify Daily

You can think of fiber like the broom of the digestive tract. Because it stays intact rather than dissolving into liquid in the intestines, it helps to clear out waste much like a sweeping broom would. This is a great thing if you’re looking to feel detoxed daily!

Now, the word “detox” has taken on a gimmicky quality recently. That’s unfortunate because our bodies actually detoxify our bloodstreams and cells—on their own—every single day when they work correctly. It’s basic human physiology. If you didn’t get rid of the waste products of enzymatic reactions, you’d die. So, detox is natural and important.

Detox doesn’t come in a special potion or pill, but rather happens naturally when you’re eating the right foods, drinking enough water, and consuming enough fiber. Here’s the science.

How Our Bodies’ Natural Detoxification Process Works

Our lymph, liver, kidney, skin, and digestive systems are “emunctory” organ systems in the body. Emunctories are responsible for excreting the harmful bioproducts of every normal enzymatic reaction in the body, as well as toxicants that we come into contact with through the environment. They’re our natural detoxification systems. 

Our liver, in particular, is responsible for filtering 100% of our blood each day. It pulls toxins and waste products out of the bloodstream, then puts these toxins through phase one and phase two detoxification. 

Next, the liver packages inactivated and compound-bound toxins into bile, which is stored in the gallbladder. The gallbladder then secretes bile into the digestive tract, where it binds to fibers. 

Finally, the toxins and the fibers they’re bound to are supposed to move out of the body as stool. In plain and simple terms—you’re supposed to poop those toxins out!

Now, imagine what happens if you don’t have enough fiber for those toxins to bind to, or if you don’t have enough fiber to produce at least one bowel movement per day. The toxins will sit in the digestive tract and be reabsorbed into the bloodstream. Over time, they build-up, and can cause problems in the body like constipation, dysbiosis, estrogen dominance symptoms (weight gain, acne, PMS, mood issues), and even things like heavy metal toxicity if you work or live in an environment where you’re regularly exposed to heavy metals, like welding. 

Without fiber, you can’t detoxify as much as you should. By focusing on the right fiber/water equation, though, you can make sure this isn’t a problem for you.

‌‌‌‌Fiber Can Benefit Gut Health

Fiber provides prebiotic starches that we need to feed healthy bacteria (also known as probiotics) in our gastrointestinal system. Probiotics are responsible for keeping our gut flora balanced by preventing the overgrowth of harmful bacteria and yeast.

Having healthy gut flora makes you less likely to experience gastrointestinal symptoms like bloating, indigestion, and food sensitivities. It also makes you more likely to experience clear skin, as we’ll explain below.

The Gut-Skin Connection and Acne

Gut health directly impacts skin health because they both have one thing in common—a microbiome. The microbiome is a collection of bacteria, yeast, and other substances that colonize our skin and mucosal surfaces. 

Studies have shown that we actually have more bacterial DNA in our bodies than we do our own DNA. That’s how important bacteria are for human health! 

A healthy gut depends on having a diverse and wild array of good bacteria, or probiotics. It helps regulate motility, immunity, and more to keep things running as they should. It also affects your overall levels of inflammation, hormone balance, and sebum production on your skin! This is because the microbiomes of the skin and gut are connected. When the gut is unhealthy, skin can become unhealthy as well.

Studies show, for example, that people who eat diets that are rich in simple sugars and low in fibrous plants are more likely to experience acne and skin rashes than those who consume lower-sugar, whole foods diets. We theorize that this could be due to changes in the microbiome. 

You can use this fact to your advantage! Eat tons of healthy fibers to keep your gut healthy, and watch your skin improve as well. 

‌‌‌‌Fiber Can Help Reduce Skin Rashes

Fiber also reduces two immune processes that can create allergic/chronic rashes and skin disorders like eczema and psoriasis.

The first is mast cell degranulation. This is a fancy term that refers to the process by which our immune cells release histamine—an excitatory molecule that makes blood vessels leaky. This leakiness, in turn, causes fluid to spread into place in our skin and organs where it shouldn’t. Have you ever gotten hives and been able to see the fluid inside of them? Or the inflammation within a bumpy rash? That’s histamine for you! 

Reducing histamine activity is one way to potentially reduce the number of rashes you experience. One study (cited in the references section below) found that dietary fiber was able to inhibit mast cell degranulation, thereby reducing the number of rashes that people experienced. It’s worth a shot to try fiber for rashes, particularly if you’ve got the support of your doctor for trying this approach. 

The second-way fiber helps to reduce certain types of skin rashes (also known as atopic dermatitis) is that it decreases the number of immunoglobulins produced by the immune system. Immunoglobulins are responsible for a number of immune system functions, including allergic response. High levels of immunoglobulins are associated with disorders like atopic dermatitis, asthma, and airborne allergies.

Key takeaway: Want your rashes to go away? Consider adding more fiber to your diet for several weeks and notice if there’s a change. Talk with your doctor about a more specific plan for your individual skin condition and mention fiber during this chat.

As you can see, fiber improves digestion, helps to prevent gut dysbiosis, reduces skin issues like rashes and acne, and can treat constipation. It’s an incredible health intervention that tastes great, costs very little, and has widespread, powerful impacts on your health. 


  1. Chen, Jia-Ping, et al. “Dietary Fiber and Metabolic Syndrome: A Meta-Analysis and Review of Related Mechanisms.” Nutrients, vol. 10, no. 1, 26 Dec. 2017, p. 24, www.ncbi.nlm.nih.gov/pmc/articles/PMC5793252/, 10.3390/nu10010024. Accessed 17 Jan. 2021.
  2. Chen, Kangning, et al. “Dietary Fiber Intake and Endometrial Cancer Risk: A Systematic Review and Meta-Analysis.” Nutrients, vol. 10, no. 7, 22 July 2018, p. 945, www.ncbi.nlm.nih.gov/pmc/articles/PMC6073518/, 10.3390/nu10070945. Accessed 17 Jan. 2021.
  3. Dai, Zhaoli, et al. “Association Between Dietary Fiber Intake and Bone Loss in the Framingham Offspring Study.” Journal of Bone and Mineral Research, vol. 33, no. 2, 7 Nov. 2017, pp. 241–249, www.ncbi.nlm.nih.gov/pmc/articles/PMC5990003/, 10.1002/jbmr.3308. Accessed 17 Jan. 2021.
  4. Folkerts, Jelle, et al. “Effect of Dietary Fiber and Metabolites on Mast Cell Activation and Mast Cell-Associated Diseases.” Frontiers in Immunology, vol. 9, 29 May 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC5992428/, 10.3389/fimmu.2018.01067. Accessed 17 Jan. 2021.
  5. Hogenkamp, Astrid, et al. “Supplementation of Mice with Specific Nondigestible Oligosaccharides during Pregnancy or Lactation Leads to Diminished Sensitization and Allergy in the Female Offspring.” The Journal of Nutrition, vol. 145, no. 5, 1 Apr. 2015, pp. 996–1002, pubmed.ncbi.nlm.nih.gov/25833889/, 10.3945/jn.115.210401. Accessed 17 Jan. 2021.
  6. Kivit, S., et al. “Galectin-9 Induced by Dietary Synbiotics Is Involved in Suppression of Allergic Symptoms in Mice and Humans.” Allergy, vol. 67, no. 3, 9 Jan. 2012, pp. 343–352, pubmed.ncbi.nlm.nih.gov/22229637/, 10.1111/j.1398-9995.2011.02771.x. Accessed 17 Jan. 2021.