March 6, 2026
Fiber is having its protein moment. Just like kale dethroned Brussels sprouts, fiber is angling for the crown in modern health culture. If it isn’t already, soon it will be in your algorithm, popping up all over your socials, and in the mouths of your favorite health influencers. It’s all for a very good reason.
Fiber is something every health-conscious person should take seriously. Are you getting enough? Are you getting the right kinds? The data is clear and the evidence is mounting. As dietary fiber intake rises, all-cause mortality risk falls. And by a significant amount.
If you want to learn more about the thrilling world of fiber and your gut microbiome, check out the deep dive from last week.
But as always, beyond the deep dive, our audience has questions. Good questions. And we like to provide insightful answers from the world’s leading experts. Today, we deliver on that promise with Dr. Federica Amati.
Dr. Amati is a medical scientist and registered nutritionist passionate about translating complex science into actionable health advice. She is the Head Nutritionist at ZOE, the gut health science and personalised nutrition company, a best-selling author, a speaker, and an educator. To learn more about Dr. Amati and ZOE, please visit her website and check her out on Instagram.
If this newsletter has been valuable to you, the best way to support it is to take a look at today’s sponsor: Momentous. They just released a new product aimed at helping people close the fiber gap without friction. It’s called Fiber+, and you can read more about it below.
It’s a fair assumption that fiber needs should scale with body size the way protein and fluids do. But fiber works differently. It isn’t absorbed and used to build body tissue the way protein is. It passes through our digestive system to the colon, where it helps in three main ways: mechanically (adding bulk and supporting regular bowel movements); as a toxin removal system (capturing waste products from the liver and moving them through and out of the body); and biochemically (feeding gut microbes and helping regulate nutrient absorption, including sugar and fats).
The fiber recommendations are based on large, population-wide research, showing a reduction in the risk of chronic diseases like heart disease and type 2 diabetes, cancer, and all-cause mortality with over 25g fiber per day. These benefits continue beyond 30g of fiber per day, with continued improvements in health as fiber intake increases up to 50g and even 90g per day. On the other hand, lower intakes are associated with a higher risk of many diseases from gut issues to metabolic illness and obesity. These health benefits (and risks) are seen at absolute intake thresholds across multiple populations and characteristics with ranges differing across ages, rather than based on intake per body size.
In America, the fiber recommendations are also calculated relative to caloric intake: 14g per 1,000 kcal. In the UK, we recommend a minimum of 30g for all adults, as the science shows us that there is no upper limit to how much fiber we should be eating: the benefits just seem to keep increasing.
A helpful way to think about it is that 30g/day is the health “floor” for improved health. For most people, the priority is getting up to that range consistently. Your “personal ceiling” is more about tolerance and appetite than a different health target.
How do you know you’re getting the right amount?
As 95% of the US population is deficient in fiber, it’s likely that you will feel “normal” even if you aren’t meeting the requirements. The most accurate method is to track your intake and count the number of plants you are eating each week. The ZOE app makes this easy, as you can simply snap a photo of your meal or snack to instantly see the total fiber content and plant count. It logs everything and keeps track for you, so you can monitor your intake without having to do the math yourself.
95% of American adults don’t get enough fiber
That's almost everyone.
As we're learning today, fiber isn't optional; it's foundational. It feeds your gut microbiome, which influences inflammation, blood sugar, cholesterol, immune signaling—even mood. Higher fiber intake is associated with a roughly 25% reduction in all-cause mortality risk.
The minimum recommendation is 25–30 grams per day. Some research suggests 40–50 grams may be even better.
Most don't get close, and achieving that through food alone isn't always realistic.
That's where Momentous Fiber+ comes in.
It’s a triple-pathway formula: soluble fiber to help regulate blood sugar and cholesterol, insoluble fiber to support digestion, and resistant starch to feed beneficial gut bacteria. Each serving delivers 6 grams of well-tolerated, functional fiber to help close the gap.
And unlike most fiber supplements, Fiber+ actually tastes good.
What matters most with fiber is not the exact time you eat it, but the total amount you get consistently, day after day, and the diversity of fiber-rich foods you consume. Having said that, a fiber-rich breakfast can help get your gut going in the morning, which is helpful for regular bowel movements.
Where timing can help is in a really practical way. If you’re thinking about blood sugar, the key is simply to have fiber with meals that contain carbohydrates. Fiber slows digestion and the absorption of glucose, so you will see a smaller post-meal blood sugar rise.
For cholesterol, it’s much more of a “what you do most days” story. Getting enough fiber consistently over weeks and months can help bring down LDL cholesterol. There isn’t a magic morning-versus-evening window.So rather than watching the clock, I’d focus on two things: work towards 30g of fiber every day, and spread it out in a way that feels good for your gut. And if you’re increasing fiber from a lower baseline (average US intake sits around 12g per day), start gradually and make sure you’re drinking enough water.
Yes. Fiber is really important for your gut, as it feeds your microbes, supports steadier blood sugar and cholesterol levels, and helps keep your digestion and appetite regulated. As with lots of things that are good for you, it’s important to take a personalized approach and listen to your body.
If you notice uncomfortable bloating, cramping, gas, diarrhea, or constipation that gets worse after increasing your intake, it’s worth making sure you slow down and speak to a registered nutrition professional for support. This can happen if you increase your fiber intake too quickly or without enough fluids.
If you have a gut condition (such as inflammatory bowel disease, Crohn's disease, ulcerative colitis, and/or celiac disease) or a sensitive gut, increasing fiber could trigger adverse responses in some people.
It’s possible that fiber can interfere with the absorption of some medications if taken together, which is why certain prescriptions will specify that they need to be taken on an empty stomach away from meals. Consult your doctor or dietitian to find the most suitable diet for you if you have a gut condition or take medication.
There is some research that suggests dietary fiber can interfere with nutrient absorption, specifically calcium, zinc, and iron. This occurs through binding of minerals, entrapment within the fiber matrix, and altered transit time.
Similar mechanisms can also interfere with medication absorption, so to minimize interactions, dietary fiber should be spaced 1–2 hours before or after oral medications.
However, it’s important to note that there are gaps in evidence for both examples, and the degree of impact is highly variable, depending on fiber type, medication type, dose, presence of other dietary inhibitors, and individual factors.
Psyllium husk has clinical benefits for cholesterol control, blood sugar regulation, and bowel function. It is also very affordable, which is a bonus, as supplements should never take away from your healthy whole food budget. It is not a universal supplement, but for people managing inconsistent digestion, cardiovascular risk, or blood sugar, the research is good. As with any supplement, timing, consistency, and adequate hydration are very important. It is a mono-fiber supplement so doesn’t provide the benefits of a varied, plant rich diet and isn’t particularly fermentable by helpful microbes, so it doesn’t help to feed your gut biome.
Dose: Most clinical trials use 3–15g per day, split into 1–3 doses. If you're new to it, begin at 3-5g/day and increase over the next few weeks. Jumping to a full dose can cause bloating and gas because your gut takes a bit of time to adjust.
How to take it: Always dissolve in a large glass of water and drink another glass immediately after. The gel needs fluid to form safely and move through the gut. Inadequately hydrated psyllium is the cause of most reported adverse events.
The views expressed by our expert are entirely their own. There is no financial, professional, or organizational affiliation between the expert featured in this Q&A and our sponsor.
Disclaimer: This newsletter is provided for educational and informational purposes only and does not constitute providing medical advice or professional services. The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice should consult with a licensed physician.
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