The Dr. Hyman Show - Office Hours: The Fiber Trend—How Much Is Too Much?

Episode Date: March 23, 2026

Fiber is having a moment—but more isn’t always better. From “fiber maxing” trends to high-fiber hacks promising weight loss and better metabolism, it’s easy to assume that piling on more fiber is the answer. In this episode of Office Hours, I break down what fiber actually does in the body, who benefits most from increasing it, and how to use it strategically to support your gut and metabolic health. In this episode, I break down: • What fiber actually does in the body—from feeding your microbiome to regulating blood sugar, cholesterol, and hormones • Who benefits most from increasing fiber (and why it can support weight loss, insulin sensitivity, and estrogen balance) • When more fiber can make things worse—especially with IBS, SIBO, or gut inflammation • How to increase fiber the right way, including types of fiber, timing, hydration, and why protein still matters Fiber isn’t a trend or a quick fix—it’s a foundational nutrient. But the goal isn’t to “max out” your intake. It’s to build metabolic and gut resilience by giving your body the right types and amounts it actually needs. When used correctly, fiber can be one of the most powerful tools for long-term health—but only when it’s personalized to your biology. Visit ⁠functionhealth.com for 160+ lab tests at just $365 a year. Have a question you’d love answered on Office Hours? Submit it here   (0:12) Welcome & Introduction to Fiber's Importance (0:33) The power, promise, and risks of fiber (3:19) Understanding fiber: Benefits and Types (6:42) Who should increase or be cautious with fiber intake (12:07) Strategies for smart fiber consumption (14:21) Fiber's role in regulating GLP-1 and overall health

Welcome to office hours. This is our dedicated one-on-one space to go deeper, get clear, and explore what truly moves the needle for your health. I'm Dr. Mark Hyman, and each week we're going to pull back the curtain and share the insights, the research, the lessons that don't always make it into our conversations with guests. Because at the end of the day, you are the CEO of your own health. And for many of you, your family's health too. And you might not feel it all the time, but you have far more power in agency than you realize. I'm glad you're here. This episode is brought to you by Function Health, empowering you to live with.

100 healthy years with over 160 lab tests at just $365 a year. Sign up today at functionhealth.com slash mark and use code Mark 2026 to get $50 towards your membership. Fibers having a moment. Now, if you've been on social media lately, you probably heard the term fiber maxing. People adding chia to everything, down in itsillium husk, game it for 40, 50, even 60 grams of fiber a day. And the problem is, well, better gut health, better blood sugar, more weight loss, natural GLP1 activation, hormone balance, and here's the thing. Fiber is incredibly powerful. In fact,

most Americans are severely deficient. We're eating about half of what our bodies actually need. And that lack of fiber is contributing to a whole list of things called constipation, metabolic dysfunction like diabetes, inflammation, and even hormone imbalances. More fiber isn't always better. Like in functional medicine, we don't chase trends. We ask better questions. So what's the goal and who does this benefit? And what happens when we push a good idea just too far? Because if your gut is inflamed, if you have irritable bowel syndrome, if your microbiome is already fragile, dramatically increasing fiber is going to make you feel worse,

not better. So today I want to unpack this trend and what fiber actually does in the body and who truly benefits from increasing it and who needs to be careful and also how to build fiber into your diet in a way that supports your metabolism, supports your hormones, your long-term health without backfiring because you don't want that because it can get bad. Fiber isn't a hack. It's not a cleanse. It's not a quick fix. It's a foundational nutrient that when use correctly can transform your health. Let's break it down. What is fiber maxing? Well, let's define this. It's exactly what it sounds like. Intentionally pushing your fiber intake way up.

We're talking 30, 40, even 50 grams of fiber a day, sometimes more. Now, people are doing it, and very specific ways. Chia puddings, loaded with seeds, cillium husk in water every morning, ultra-high fiber cereals, gut cleanse protocols, fiber powder, supplements stacked on top of whole foods. It becomes almost a badge of honor.

How high can you go? Well, why is this trending? Because fiber works. It helps with weight loss. It blends blood sugar spikes. It feeds your microbiome. It's good. It helps you feel full.

It can even simulate your body's natural GLP1 hormone, the same pathway targeted by drugs like OZemping. And for many women, fiber also helps support estrogen detoxification and hormone balance and gets everything working in the hormone scene. So the excitement makes sense. So at its core, fiber maxing aims to accomplish something real.

It's trying to help you feel fuller, longer, so you don't need so much. It lowers spikes in insulin, which makes you gain weight. It's a fast storage hormone. It supports a healthier microbiome because fiber feeds the microbiome. It helps you go to the bathroom and have regular bowel, because you need fiber to go poop. And it assists in your body's clearing excess hormones through your gut. All these are really good goals.

But here's the functional medicine lens. The goal isn't maximum fiber. The goal is metabolic resilience. The goal is gut resilience. More isn't automatically better. Smarter is better. And the real question isn't, how much fiber can I tolerate,

which, you know, you get used to more and more. What does my body actually need? What does my biology actually need? Now let's talk about why fiber actually matters, because this isn't just about digestion. Fiber is one of the most important, powerful, underappreciated nutrients in the modern diet. First, fiber feeds your microbiome. You're not just eating for yourself, you're eating for your gut bacteria. And your microbiome isn't just about, you know, gut comfort or regularity.

It's about how the microbiome influences your immune system, your metabolism, your brain chemistry, even your mood. Now, when certain fibers are fermented by gut bacteria, and they produce something called short chain fatty acids, especially something called buterate. It smells bad, but it's really good for you. Buterate helps strengthen the gut lining. It also reduces inflammation, and it improves your insulin sensitivity. It actually even helps prevent cancer, by the way. It's one of the key molecules that keeps your metabolic system running smoothly. Now, fiber also helps regulate cholesterol by binding bile acids and helping your body eliminate excess cholesterol. It slows glucose absorption, which means you have fewer blood sugar spikes, fewer insulin,

insulin surgeries and more stable energy, which is good because people want that. And for many people, especially women, who are navigating a lot of the hormonal shifts that come with perimenopause and menopause or even PMS, fiber helps bind excess estrogen and also excess toxins in the gut. So they can be eliminated and don't affect your hormones. And that really helps create hormonal balance. Now, there's a key distinction you should know about. Not all fiber is the same.

Now here's where nuance matters. Some fiber is soluble, meaning it dissolves in warm. water. It forms as gel-like substance, and it feeds your gut bacteria. Think oats, chia, cillium. Some fiber is insoluble. It adds bulk to your diet. It helps move things through your digestive tract and helps you poop. Think leafy greens, vegetable skins, seeds. And then there's fermentable versus non-fermentable fiber. You know, some fibers are easily fermented by the gut bacteria, which is really beneficial. But for someone with an irritable bowel syndrome problem, or small intestinal bacterial overgrowth,

too much fermentable fiber all at once can cause bloating, discomfort, and make things worse. Not that you don't need it eventually, but in the short term, you have to fix the problem. So when we talk about fiber, we can't treat it like one single thing. From a functional medicine perspective, fiber is a tool.

And like any tool, it has to match the biology of the whole person using it. The goal isn't just more fiber. It's the right types of fiber in the right amounts for your body, not just anybody else. So fiber is not just about pooping, which is it's about metabolic signaling, which is very important. So who actually benefits from increasing fiber? Thoughtfully, not recklessly. Who benefits? When done correctly,

high fiber intake is an incredibly powerful tool for the right people. And let's look at who that is. First, anybody dealing with insulin resistance, by the way, which was almost 90% of the population, or pre-diabetes, fiber slows the absorption of glucose, which is really important. And that means fewer blood sugar spikes. It means less insulin flooding your system, and that's important because insulin is a fat storage hormone, and it means more stable energy throughout the day. And certain fibers actually stimulate your body's natural GLP1 production,

the same appetite regulating hormone that's targeted by popular weight loss medications like OZemPEC, except this is your body doing it naturally. If you're struggling with cravings, energy crashes, or sudden stubborn weight gain around the middle, well, fiber can be a game changer. Another great use of fiber is for people who are suffering from parimenopause or PMS or a lot of hormonal shifts. Now, when estrogen levels fluctuate,

many women experience a lot of changes in their bodies like fat distribution, maybe increased belly fat. Fiber also helps improve insulin sensitivity, which directly impacts this pattern. It also binds extra estrogen that's in your gut and supports proper detoxification, which means you don't have too much circulating estrogen in your body, which can cause all kinds of problems from PMS to breast cancer and many other things. This is not just a trendy claim.

This is just basic human physiology. Next big thing that fiber helps is constipation, which affects a lot of people. So when you have this slow transit time in your gut, when you increase fiber and when things aren't moving and you add the right types of fiber gradually, and then by the way, with enough water, because if you just have fiber without water, it's like cement.

So you don't want to do that. When you do that, it can really improve going very early, which is every day. I had a patient once and I said, how often you go? She goes, I'm regular. I said, well, how often you go? She goes, I go once a week. I'm like, that's not regular. She goes regular for me.

It should be once or twice a day, folks. So basically you have to make sure you get the right amount for you, it's slowly built up. But ideally, fiber is really important for having regular, healthy bowel movements. The next big thing that can help with is your cholesterol, high LDL cholesterol, high APOB, soluble fiber, things like steel cut oats, flax, cillium, they can bind to the bile acids in your gut and they help reduce the circulating cholesterol. And it's one of the most evidence-based back benefits of fiber. So this is a lot of research on this.

And those who are also eating ultra-processed diets, but honestly, you don't want to eat that anyway. But if you eat those, those foods are just empty of fiber. They're rapidly absorbed. They spike your blood sugar. hungry, they're just bad, and they make, you know, us all sick, which is what's happening in America today. So now, if you're one of those people eats ultra-processed foods, first of all, you shouldn't. But second of all, increasing fiber really helps correct this deficiency of fiber in your diet. So yes, fiber maxing, when done intelligently, and I don't like that term, by the way,

can be incredibly helpful. But it works best when it's addressing a real metabolic knee, not just chasing a trendy thing you've watched on Instagram or TikTok. Okay. So who should be a little cautious about eating too much fiber, right? It's time to track more than the weather. Your body has seasons too. In winter, your vitamin D levels and immune system may shift in response to those cool, cold, dark days. By the time spring shows up, your biology transitions again.

And here's the part the majority of us miss. These changes can happen quietly. You won't feel them, you won't see them, and you won't catch them without data. And that's why spring is a perfect moment to measure what's actually going on inside. Function gives you 160 lab test so you can stay on top of your vitamin D levels, your hormone balance, your inflammation patterns, and lots more. You can join in Functionhealth.com for $365 a year. That's literally a dollar a day. Nature's resetting. Make sure your body does too. Let's talk about the other side of this conversation. While eating fiber can be incredibly powerful,

more isn't always better, especially if your gut is not ready for it. And this is where personalization and nuance matters. And a lot of people suffer from irritable bowel, from bloating, from what we call sebo or small intestinal bacterial overgrowth. If you're struggling with these things, dramatically increasing fermentable fiber actually makes you worse in the short term. In the long term, it can help. But in the short term, it's going to cause a problem because fermentable fibers feed the bad bugs as well as the good bugs. And if bacteria overgrowing in the wrong place, like your small intestine, you're essentially pouring fuel on the fire and you're going to get more gas, more more dissension, more discomfort. So in those cases, we don't start with more fiber. We start with

healing the gut. And there's a very important method for doing that. We call the five-hour program in functional medicine, but it's really important. Second, anyone with active gut inflammation, whether it's inflammatory bowel disease or post-antibiotic gut disruption or significant leaky gut symptoms, you need a more personalized approach because certain fibers will irritate an already inflamed intestinal lining. Now, again, the goal is in volume. The goal is just to repair your gut. Another area to be cautious is thyroid patients, especially those taking thyroid medication, because if you're eating a very high fiber intake, that can interfere with the absorption of certain medications if you take it too close together. It doesn't mean avoiding fiber. It means about

being strategic about timing, so you're not absorbing the drugs as well as the sugar. Now, I want to talk about something that often gets overlooked. Some people start fibromaxing, but they're under-eating protein. They're adding chia pudding, flax crackers, fiber cereal, but they're not getting adequate protein to support building muscle. And especially as we age, muscle is critical for metabolic health, for blood sugar control, for longevity. Now, if fiber crowds out protein, you're solving one problem and you're creating another problem. So be careful.

The functional medicine rule is if your guts inflamed, heal that first, don't overload it. Don't force feed the gut microbiome. You want to make sure you have healthy bugs, build them up slowly. And slowly you build resilience and you can tolerate a lot more fiber. fiber is very powerful, but only when your biology is ready for. Okay, so if you're going to increase your fiber intake, let's do it in a smart way. First rule, go slowly. Your microbiome adapts over time.

Now, if you jump from 15 grams to 45 or 60 overnight, you're not going to be happy, and you're going to have issues. So it's slowly increased by about 5 grams of fiber a week, and then kind of let your system adjust. Second big point here is hydration is mandatory. It's non-negotiable. because fiber absorbs water. And if you increase fiber without fluids, you're actually going to worsen constipation.

Fiber is like a sponge, and it needs water to do its job. And if you have fiber without water, it turns to cement, and that is no fun for anybody. Next, pair your fiber with protein. That's critical because it helps with feeling full. It helps with blood sugar control.

But protein also preserves muscle, and it stabilizes your metabolism, and it supports your long-term overall, resilience of your health. So every fiber forward meal should also include high-quality protein. Next thing you want to do is focus on whole food sources of fiber. The best fiber comes packaged with nutrients, phytonutrients and minerals, like lentils, beans if you can tolerate them, chia seeds, flax seeds, artichokes, berries, veggies of all kind. A whole diversity of foods feeds a diverse microbiome. Next, be careful with ultra-processed high fiber products. My rule is if it has

a health claim on the label, do not eat it. It's bad for you. If it says high fiber, it's hiding something. If it says high protein, it's hiding something like sugar. So be careful. Fiber bars are often loaded with sugar, artificial sweeteners. Cereals fortified with synthetic fibers are not good for you. It's manufactured to look healthy, but read the label carefully and basically follow my rule. If it has a health claim on the label, don't eat it. Next, figure out what amount matters for you. diversity of fiber is really important. So not just all from the same source, like cillium husk or flaxseeds. 30 grams of varied plant fiber is even more beneficial than 60 grams of one isolated supplement

like flaxseeds or cillium husk. So here's a takeaway. From a functional method perspective, the goal is to win the fiber Olympics. It's to create a resilient gut, a stable blood sugar, balanced hormones, and sustainable energy. More is not the goal, better is. Now let's talk about why fiber is getting so much attention right now. GLP1. You've heard about Ozempic, Wagovi,

all those medications that increase GLP1 to reduce appetite and improve your blood sugar. But here's what most people don't realize. Your body already makes GLP1. And one of the most powerful ways to simulate it naturally is through fiber, especially soluble fiber and fermentable fiber. When fiber reaches your colon, it feeds your beneficial bacteria. and those bacteria produce short chain fatty acids. Those compounds signal your body to increase JLP1 production,

and that helps regulate your appetite, improve insulin sensitivity, and stabilize your blood sugar. So yes, fiber can support natural appetite regulation. But here's the nuance. Fiber alone is not a magic bullet. If you're not sleeping, if you're not strength training, if your protein intake is low, if your stress is chronically high,

fiber is not going to fix that. It's not going to override those signals. So a GLP1 isn't just about food. It's about metabolic health as a whole. Fibre is part of the solution, but it works much better inside a bigger framework of understanding metabolic resilience. All right, let's do a quick Q&A on fiber.

Is cillium good? Well, yeah, if you use strategically, and it's tolerated. Is too much fiber bad? Well, yes, it can be bad in the wrong situations, and you can get bloating, you can get poor absorption of other things like minerals, so be careful.

Next question. Should I fiber max if I'm trying to lose weight? Yes, but with protein intake that's adequate and strength training or resistance training. Next question. Can fiber lower estrogen dominance, which means too much estrogen, which can cause weight gain, fluid retention, breast tenderness, PMS, hot flashes, all kinds of stuff, even cancer. Yes, it actually can help by binding excess estrogen in the gut and pro tip flax seeds are particularly good at this. All right, let's zoom out. Fibermaxing isn't wrong.

In fact, for lots of people, increasing fiber is one of the smartest changes they can make in their diet. But health doesn't come from extremes. It comes from alignment. The real goal isn't the max amount of fiber. It's metabolic resilience. It's gut resilience. It's sustainable energy. It's sustainable hormones.

If your digestion improves, your energy stabilizes, your cravings decrease, then you're on the right track. But if you're bloated, you're inflamed, you're uncomfortable, that's data your body's giving you. Listen to your biology. If this episode helped you cut through the noise around the fiber trends, well, share it with someone experimenting with fibramaxing or trying to improve their gut health. And remember, the body responds to balance non-intensity, smarter, not harder. Thanks for joining me for office hours. I love diving into these topics with you.

Remember, you are the CEO of your own health. And every choice you make can move you closer to healing and vitality. I want to keep these episodes as relevant and useful as possible, so tell me, what do you want to explore next? What questions are you wrestling with? What breakthroughs are you chasing? Share your ideas in the comments on social media or through the link in the show notes. I'm listening. Until next time, keep taking charge, keep asking questions, and keep showing up for your health. If you love this podcast, please share it with someone else you think would also enjoy it.

You can find me on all social media channels at Dr. Mark, Hyman. Please reach out. I'd love to hear your comments and questions. Don't forget to rate, review, and subscribe to the Dr. Hyman show wherever you get your podcasts. And don't forget to check out my YouTube channel at Dr. Mark Hyman for video versions of this podcast and more. Thank you so much again for tuning in. We'll see you next time on the Dr. Hyman Show. This podcast is separate from my clinical practice at the Ultra Wellness Center, my work at Cleveland Clinic and Function Health, where I am chief medical officer. This podcast represents my opinions and my guest's opinions. Neither myself nor the podcast endorses the views or

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