There are countless dietary approaches, each touting its own unique benefits and restrictions. Gastroenterologist Dr. Will Bulsiewicz, author of Fiber Fueled, champions a simple yet powerful rule for a healthy diet: consume enough fiber, and ensure it's from diverse sources.
The Fiber Fueled Journey: From Personal Struggle to Dietary Revolution
Dr. Bulsiewicz's journey to becoming a proponent of fiber-rich diets began with his own health struggles. During his residency, he neglected his well-being, relying on fast food and energy drinks while working long hours. This lifestyle took a toll on his body, leading to weight gain and other health issues. He tried exercising his way out of the problem, completing grueling, hours-long workouts every day to try to lose the excess weight, but it didn’t work. His initial attempts to rectify the situation through exercise proved futile.
A pivotal moment occurred when he met his wife, whose plant-based diet contrasted sharply with his meat-heavy consumption. This encounter sparked his curiosity and led him to explore the scientific literature on nutrition. Based on what he’d learned, Dr. Bulsiewicz changed his diet completely and prioritized eating fiber-and only then was he finally able to lose the weight and his other symptoms. The research he conducted transformed his understanding of nutrition and ultimately led to a complete dietary overhaul centered around fiber.
Understanding Fiber: More Than Just a "Torpedo"
Fiber is a part of plants. Every plant has fiber in it, and plants are the only thing that contain dietary fiber. Fiber, found exclusively in plant foods, serves as a prebiotic that nourishes beneficial gut bacteria. Dietary fiber, classified as a non-digestible carbohydrate, stands apart from other carbohydrates, such as starches and sugars, due to its unique behavior within the digestive system. In the colon, intestinal bacteria, known as gut microbes, have the enzymes needed to digest many types of fiber. This microbial digestion of fiber yields short-chain fatty acids (SCFAs), which have significant documented health benefits.
Contrary to the common misconception that fiber simply passes through the digestive system, it plays a much more complex role. There are tons of different types of dietary fiber - so many that we actually have no idea of the number. “There’s not even an estimate because it’s so structurally complex,” he says. It's crucial to understand that "fiber is not just fiber." The source of the fiber you consume matters a lot. Fiber can be broadly categorized into two types: soluble and insoluble.
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Soluble Fiber: The Gut Microbiome's Best Friend
Soluble fiber, as Dr. Bulsiewicz emphasizes, dissolves in water. This type of fiber is prebiotic, which means it feeds and nourishes the microbes in your gut. The power of soluble fiber comes from the fact that soluble fiber is prebiotic, which means it feeds and nourishes the microbes in your gut. Soluble fiber passes through the small intestine untouched, then enters the large intestine, or colon, which is the predominant location of your microbiome - in other words, it’s where most of your microbes live. This is where the soluble fiber benefits kick in.
Now that it has helped produce more anti-inflammatory microbes, the microbes turn around and pay you back for the food by releasing what Dr. Bulsiewicz calls “the biggest secret in all of nutrition:” short-chain fatty acids. These short-chain fatty acids, which are actually postbiotic compounds, are incredibly healing. These SCFAs are a "biggest secret in all of nutrition" and are incredibly healing. One of the points that Dr. Bulsiewicz emphasizes in his practice is the importance of food diversity in your diet. Based on his research and experience, he believes that eating food in abundance, and eating many different types of food, is essential.
Insoluble Fiber: The "Torpedo" We Know
Insoluble fiber, on the other hand, will never dissolve no matter how much you stir. Dr. Bulsiewicz says that most of us have been taught to believe that “fiber goes in the mouth and it goes through the intestine and it launches out the other end like a torpedo” - but in reality, this only applies to insoluble fiber, not soluble fiber. It adds bulk to the stool and aids in regular bowel movements.
The Importance of Food Diversity: Feeding a Thriving Microbiome
One of the points that Dr. Bulsiewicz emphasizes in his practice is the importance of food diversity in your diet. Based on his research and experience, he believes that eating food in abundance, and eating many different types of food, is essential. The plan gradually introduces plant diversity. What he’s proposing is quite different, and quite straight-forward: “There’s one rule. It’s simple. You don’t need to count your calories. You don’t need to weigh your food. You don’t need to worry about macros.
So why does food diversity and diversity of plants matter so much? It all comes back to those soluble fiber benefits. Remember how soluble fiber feeds the microbes in your gut? Well, all of those microbes eat different types of dietary fiber, and because every type of plant contains its own mix of fiber, you need to eat many different types of plants to keep all your healthy microbes satisfied. Microbial diversity is crucial. The human gut contains 39 trillion microorganisms, including bacteria, yeasts, parasites, viruses, and archaea. Dysbiosis leads to disease. When the gut microbiome loses diversity and balance, it can result in increased intestinal permeability ("leaky gut") and the release of bacterial endotoxins.
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While this argument for food diversity makes sense on an intuitive level, there’s also hard research to back it up. Dr. Bulsiewicz cites the largest study to date - including more than 11,000 people - which correlated diet and lifestyle with the diversity (and thus the health) of the gut microbiome. This study demonstrated a strong correlation between dietary diversity and a healthy gut microbiome.
The Downside of Restrictive Diets: A Warning Against Categorical Elimination
So what happens when you turn away from food diversity and start eliminating categories of food from your diet? Dr. Bulsiewicz says that it’s “not the end of the world” if you turn away from one food or a small category of foods. Where things get troublesome is when it comes to categorical elimination: for instance, the elimination of legumes or whole grains, two food categories that are commonly cut out on various diets.
“The studies are very consistent in their findings, whether it is looking at a gluten-free diet, whether it is looking at a low-FODMAP diet, whether it’s looking at the paleo diet, where people completely eliminate whole grains and legumes,” says Dr. Bulsiewicz. This is because there are specific microbes in your gut that thrive when you consume legumes, so if you get rid of legumes entirely, those microbes die. Similarly, there are healthful microbes that survive on the consumption of whole grains, as well as harmful microbes that thrive in their absence. Going Gluten-Free may not be good for everyone. By depriving oneself of gluten, we may actually lose part of your carbohydrate-processing ability, making our guts weaker and less adapted to processing and unpacking complex carbs.
Eliminating entire food groups can have detrimental effects on the gut microbiome, leading to a decrease in microbial diversity and potentially impacting overall health.
Practical Steps to Embrace a Fiber Fueled Lifestyle
Embracing a fiber-rich diet can be transformative for our health, and the journey begins with prioritizing whole, unprocessed foods over their processed counterparts. How many plant-based whole foods do we need daily to meet the fiber requirements? A plant-focused diet is crucial for meeting daily fiber requirements. Aim for 2-4 servings of fruit, 3 servings of whole grains, unlimited non-starchy vegetables, and 1 ounce of nuts or seeds daily. Starchy vegetables like potatoes, peas, and corn contribute to fiber intake.
Read also: Gut Health on Carnivore Diet
Here's a breakdown of how to incorporate the principles of the Fiber Fueled diet into your daily life:
- Prioritize Plant Diversity: Aim for 30+ plant foods per week. Embrace whole plant foods. Focus on minimally processed plant foods rather than refined or processed versions. A diverse diet leads to a diverse gut microbiome. Research from the American Gut Project found that consuming more than 30 different plant foods weekly results in a more varied gut microbiome than those with fewer than 10 plant varieties.
- Embrace F GOALS: F.G.O.A.L.S. Incorporate these foods regularly. Choose organic when possible. F GOALS plants are thin-skinned foods. There's no rind or skin to peel away, with the exception of onions and garlic.
- Go Low and Slow: Go low and slow when adding fiber to your diet. There is no need to rush and add all the high-fiber foods you can in one day. Instead, gradually add fiber-containing foods over time, allowing your body to adjust. Increase fiber intake as tolerated and make sure you stay hydrated. Increasing fiber intake too quickly or while dehydrated generally could lead to increased gastrointestinal symptoms.
- Incorporate Fermented Foods Gradually: Incorporate fermented foods gradually. Start with small amounts and increase slowly to allow your gut to adapt. Fermented Foods have tremendous health benefits for the gut. It is one of the few examples of food preservation that actually makes our food even more healthy.
- Develop a Health Mindset: Practice mindful eating. Pay attention to your food, eat slowly, and listen to your body's hunger and fullness cues.
The Gut-Brain Connection: Fiber's Impact on Mental Well-being
Are you looking to add foods to your diet that will give you an extra boost of energy, happiness and emotional well-being? So, how exactly does this fibrous friend do so much? First, we should take a look at a little something called the gut-brain axis. It has long been thought that your brain is the control center of your body and that it tells your organs what to do. Your gut, in fact, is called your second brain and houses something called the enteric nervous system. Over 90% of the serotonin in your body (the “happiness hormone”) and 50% of your dopamine (the “feel good hormone”) is made there. These molecules influence mood, sleep, energy and gut motility.
What is the microbiome you ask, and what does it have to do with fiber and mental health? Excellent questions! Your microbiome is composed of over thirty-nine trillion (with a T) microorganisms that live in your colon! Isn’t that crazy! Seriously though, your microbiome is an ecosystem that allows things to go swimmingly when balanced (good outweighing the bad bacteria), and you feel great. The bad bacteria take over and cause an inflammatory cascade that is associated with leaky gut. This can lead to numerous, unfavorable health conditions, one of which is irritable bowel syndrome (IBS). So, how do you ensure that your gut bacteria are getting along with each other? The answer is diet! The food you eat feeds all of your little bacterial friends. Foods high in saturated fat and refined sugar and low in fiber are known to derail your intestinal happiness. Dr. So, dig in. Embrace eating the rainbow and providing diversity in the plant foods you consume.
The Standard American Diet (SAD) and the Importance of Reversing the Trend
The Standard American Diet is predominantly composed of refined and processed foods, constituting a startling 63% of the diet. This includes soft drinks, packaged snacks, chips, desserts, and more. Animal-based products contribute 25% of dietary intake, leaving only 12% for plant-based foods. Overreliance on medication. It's crucial to shift away from this dietary pattern and prioritize plant-based, fiber-rich foods.
Beyond Gut Health: The Long-Term Benefits of a Fiber Fueled Diet
This isn't a twenty-eight day plan that you do as an isolated event. Long-term benefits extend beyond gut health. Fiber supports gut health by nourishing gut bacteria and producing essential SCFAs. Additionally, fiber promotes regularity, lowers cholesterol levels, reduces the risk of diabetes, and provides better blood sugar stability for those with diabetes. Furthermore, fiber is associated with a decreased risk of several types of cancer, including breast, ovarian, endometrial, and colon cancer.
Recommended Fiber Intake: How Much Do We Need?
How much fiber is recommended daily? The Institute of Medicine recommends 25 grams of fiber for women and 38 grams for men under age 50. For those over 50, the daily recommended fiber intake is slightly lower at 21 grams for women and 30 grams for men.
Priming the Gut for Fiber: A Pre-Fiber Fueled Approach
Some of us may currently have trouble digesting raw plant fibers, which will hinder this healing experience. This works to jump start Bifidobacteria and Akkermansia production, which will in-turn strengthen our gut lining and repair butyrate transport. These are powerful tools that can properly prime the body prior to starting the Fiber Fueled Diet Plan. This will maximize your body’s ability to breakdown and ferment these plant fibers. These will be best consumed at breakfast for 1-2 weeks prior to starting Fiber Fueled.
Going primarily plant-based in the short-term can be a remarkable healing experience. It’s important to remember that we as humans, are seasonal eaters. This is how we evolved. Different seasons brought on abundance of various food sources, or lack thereof. The body is extremely intelligent in its ability to learn and adapt to our eating habits. For example, if you are eating too much of one food, your body can eventually reject it and develop an allergy.
Personalization and Flexibility: Tailoring the Fiber Fueled Plan to Your Needs
This plan was created to fit the uniqueness of each and every individual. With our own individuality at the forefront of our mind, we must remember that the rules are meant to be bent. Use your journal to rank recipes from your enjoyment - perhaps on a scale from 1-10. This ranking system should be based on your taste, preference, convenience, enjoyment, and overall satisfaction.
The Fiber Fueled Plan does not track your caloric intake but rather how many different plants you use at each meal. Your total number of plant points will be calculated for the week in sum. Note, that each recipe card below will include the total number of plant points for that meal. This point system is designed to keep track of your overall plant diversity. We will become gut health masters as we begin this new and exciting culinary journey. The point system is here to help you and remind you to increase diversity over time. With patience, we will begin to notice that it takes less effort to search for foods we know we’ll love at the grocery store.
Monitoring Progress and Embracing the Journey
We are just getting started. This is where we experience the real change. Here, we should notice better energy levels, more restful sleep, and overall, less inflammation in the body. Changes in your gut are underway. Your gut microbiome is shifting for the better. Pushing yourself to achieve greatness! A fiber fueled god of rock. Welcome to the world of microbiome diversity.