Office Hours: The Fiber Trend—How Much Is Too Much?

[Music] Welcome to Office Hours. This is our dedicated 101 space to go deeper, get clear, and explore what truly moves the needle for your health. I'm Dr. Mark Heim in 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 and agency than you realize. I'm glad you're here. [Music] This episode is brought to you by FunctionHealth empowering you to live 100 healthy years with over 160 lab tests at just $365 a year. Sign up today at functionhealth.com/mark and use code Mark2026 to get $50 towards your membership. Fibers have in a moment. Now, if you've been on social media lately, probably heard the term fiber maxing. People adding chia to everything, down in Slamhust, gamut for 40, 50, even 60 grams of fiber a day. And the promise will better get 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 now like a 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, and your long-term health without backfire, because you don't want that because it can get bad. Fiber isn't a hack. It's not a clan. It's not a quick fix. It's a foundational nutrient that when used correctly can transform your health. Let's break it down. What is fiber maxing? 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 days. Sometimes more. Now people are doing it in very specific ways. She of puddings loaded with seeds, psyllium husk and water remorning, ultra high fiber cereals, gut cleanse protocols, fiber powders, 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 ozimpyc. 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-sourge hormone. It supports a healthier microbiome because fiber feeds the microbiome. It helps you go to the bathroom and have regular bowel movements because you need fiber to go poop. And it assists in your body's clearing excess hormones through your gut. All of 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 is an 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, they produce something called short-chain fatty acids, especially something called butyrate. It smells bad, but it's really good for you. Butyrate helps strengthen the gut lining. It also reduces inflammation and it improves your insulin sensitivity. It actually even helps strengthen 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 surges, and more stable energy, which is good because people want that. And for many people, especially women who are navigating a lot of their hormonal shifts to come with paramedics 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 nuanced matters. Some fiber is soluble, meaning it dissolves in water. It forms its gel-like substance and it feeds your gut bacteria. Think oats, chia, psyllium. 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. Now some fibers are easily fermented by the gut bacteria, which is really beneficial. But for someone with an irritable balance in general problem or a small intestinal bacterial overgrowth, too much fermentable fiber all at once can cause bloating, discomfort, and making it 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 treat 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 prediabetes, 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 OZMPEC. Except this is your body doing it naturally. If you're struggling with cravings, energy crashes, or sudden stubborn weight gain around the middle, fiber can be a game changer. Another great use of fibers are people who are suffering from paramedicause, or PMS, or a lot of hormonal shifts. Now, when estrogen almost fluctuates, 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 the 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 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 regularly, which is every day. I had a patient once and I said, "How can you go?" She goes, "I'm regular." I said, "Well, how can 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 it's basically you have to make sure you get the right amount for you and slowly build 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 it will be soluble fiber. Things like steel cutouts, flax, cillium. They combine to the bile acids in your gut and they help reduce the circulating cholesterol. 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-process diets, but honestly, you don't want to eat that anyway, but if you eat those foods are just empty of fiber. They're just rapidly absorbed. They spike your blood sugar, they make you hungry, they're just bad. They make us all sick, which is what's happening in America today. So now, if you're one of those people, it's ultra-process 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 need, not just chasing a trendy thing. 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 two. 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 a 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 SIBO 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. 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 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 5R program in functional medicine, but it's really important. As 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 and 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, does it mean avoiding fiber? It means about being strategic about timings or not absorbing the drugs as well as the sugar. Now, I want to talk about something that often gets overlooked. Some people start fiber-maximity, 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 and troll, 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 gut's inflamed, heal at first, don't overload it, don't force feed the gut microbiome, you want to make sure you have healthy bugs, build them up solely, 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, feel slowly. Your microbiome adapts over time. Now, if you jump from 15 grams to 45 or 60 overnight, you're going to be not going to be happy and you're going to have issues. So it's slowly increased by about five grams of fiber a week, and then kind of let your system adjust. Second big point here is hydration is mandatory. It's not 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 into 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 source 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 or 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 a mount matters for you. Diversity of fiber is really important. So not just all from the same source, like silicon husk or flax seeds. 30 grams of varied plant fiber is even more beneficial than 60 grams of one isolated supplement like flax seeds or silicon husk. So here's a takeaway. From a functional minute perspective, the goal is to win the fiber Olympics. Instacredeous resilient got a stable blood sugar, downed swarimones and sustainable energy. More is not the goal that or is. Now let's talk about why fibrous getting so much attention right now. GLP1, you've heard about Hosempic, Wagowi, all those medications that increase GLP1 to reduce appetite and improve your blood sugar. But here's the most people that realize your body already makes GLP1 and one of the most powerful ways to simulate it naturally is to 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 that your body to increase GLP1 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 string training, if you're 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 GLP1 isn't just about food. It's about metabolic health as a whole. A fiber 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. It's still good. Well, yeah, if you strategically and is tolerated, it's too much fiber bad. Well, yes, it can be bad in the wrong situations and you can get bloating, you can get poor absorption if 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, this 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, rest 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. Flaxids are particularly good at this. All right, let's zoom out. Fiber maxing 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 a sustainable energy. It's a sustainable hormones. If your digestion improves your energy stabilizes. Your cravings decrease, and 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 with someone experimenting with fiber maxing or trying to improve their gut health. And remember, the body responds to balanced not 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. Do you have a question about my favorite books, supplements, or recipes? Then sign up for my free MarxPix newsletter at drheimen.com/markspix, where I'll share all of this information with you and so much more. You'll get emails from me every Friday with recommendations on things that have helped me on my health journey, and I hope they can help you too. Thank you so much again for tuning in. We'll see you next week on the Dr. Heimichau. 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 Heimen. 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