Live Well, Age Well

Protein has had a very good decade. It is on the front of every package, in every ad, at the center of every conversation about staying strong as we age. And it deserves the attention. I have spent three posts in this series making that case myself. Fiber has had a very different decade. Nobody is arguing about it. Nobody is marketing it. There is no fiber influencer. And that quiet is exactly the problem, because fiber is the nutrient with one of the widest gaps between what we need and what we actually eat. How wide? Researchers analyzing national nutrition survey data from more than 14,000 U.S. adults found that roughly 7% of adults meet the daily fiber recommendation — about 5% of men and 9% of women. The rest of us are somewhere below the line, most of us well below it. Average intake sits near 16 grams a day against targets of roughly 25 grams for women and 38 grams for men. We are not slightly short. We are, as a country, eating about half the fiber we need. And the reason that matters has almost nothing to do with what most people think fiber is for. Fiber is not a digestion nutrient. It is an aging nutrient. Most of us learned about fiber in the narrowest possible terms. It keeps you regular. It is what you take when something is wrong. It lives in the pharmacy aisle next to things nobody wants to discuss. That framing is not wrong, exactly. It is just so small that it misses the actual story. Here is the bigger version. Your large intestine houses a population of bacteria that you cannot live well without. Those bacteria have a job, and the job is fermentation — breaking down the fibers you cannot digest yourself and producing compounds called short-chain fatty acids as a byproduct. Butyrate is the one worth knowing by name. It is the preferred fuel source for the cells lining your colon, and it is central to keeping the intestinal barrier intact. That barrier is the thing that matters as our bodies change. Reviews of the aging gut describe a consistent pattern: microbial diversity tends to decline with age, the bacteria that produce short-chain fatty acids become less abundant, and the tight junctions that hold the intestinal barrier together lose some of their integrity. Researchers connect that combination to inflammaging — the persistent, low-grade inflammation that shows up as a hallmark of aging across nearly every system in the body. In other words: the gut does not just get less comfortable as we age. It gets less protective. And the primary thing you can feed the bacteria that hold that line is fiber. The number that made me pay attention Researchers following more than 1,600 adults aged 50 and older for a decade looked at which dietary factor best predicted what they called successful aging — reaching the end of the follow-up period free of disability, depressive symptoms, cognitive impairment, respiratory symptoms, and chronic disease. They tested total carbohydrate intake. Glycemic index. Glycemic load. Total sugar. Fiber was the strongest predictor of the group. Participants in the highest fiber intake group had close to an 80% greater likelihood of aging well over those ten years. One observational study is not proof of cause. But when the nutrient nobody markets outperforms every other carbohydrate variable in the analysis, that is worth more than a shrug. Some fiber feeds your gut. Some just passes through. Here is where the label gets interesting, and where a lot of well-intentioned shopping goes sideways. "Fiber" on a Nutrition Facts panel is a regulatory category, not a description of what something does in your body. It covers a wide range of compounds that share one trait — your small intestine cannot break them down — and almost nothing else. Some pass through largely inert, adding bulk and not much more. Some form a gel that slows digestion. And some are actively fermented by your gut bacteria, which is the category that produces the short-chain fatty acids we just talked about. That last group has a name: prebiotic fiber. A prebiotic is not a probiotic. You are not swallowing bacteria. You are sending food to the bacteria you already have, which is a considerably more reliable proposition than hoping a capsule of live cultures survives the trip. Inulin, the fiber found in chicory root, is one of the best-studied prebiotic fibers there is. In a randomized, placebo-controlled trial of 55 adults, dried chicory root increased fecal acetate, propionate, and butyrate by about 26%, with matching increases in circulating levels. Bifidobacterium and Anaerostipes — two groups central to that fermentation chain — increased three- to fourfold. Stool softness and bowel frequency improved. The effects appeared quickly and reversed when the fiber was withdrawn, which is its own kind of evidence: the bacteria respond to what you actually feed them, this week, not to what you ate five years ago. That is the distinction worth carrying into a store. The question is not how many grams of fiber. The question is what kind, and whether it does anything once it arrives. The source matters more than the number This is the part of the label conversation that almost nobody has, and it is the reason we built our bars the way we did. When the FDA modernized the Nutrition Facts panel, it did something that sounds bureaucratic and turned out to be consequential: it decided that a compound can only be counted on the Dietary Fiber line if there is evidence it produces a beneficial physiological effect in humans. Not just that it resists digestion. That it does something. Then the agency published a list. Inulin and inulin-type fructans — chicory root fiber — made the list in June 2018. Isomaltooligosaccharide, almost always labeled as IMO, did not. Two separate manufacturer petitions asked the FDA to add it. In January 2020 the agency denied both, concluding that the strength of the evidence did not show a beneficial physiological effect in humans. Now put that next to a shelf of high-fiber bars. IMO syrup is one of the most widely used ingredients in the bar category. It is inexpensive, it binds beautifully, it tastes mildly sweet, and for years it was counted as fiber. After the FDA’s decision, it cannot be. Which means a bar built on IMO either has to reformulate, or watch its fiber number fall. What this means when you read a panel If a bar shows a large Dietary Fiber number today, that number is legally required to come from fibers the FDA recognizes. The grams on the line are real. What the line will not tell you is whether the rest of the bar's bulk comes from something the agency has specifically declined to count — that information is in the ingredient list, not the panel.   So let me be direct about our own label, because we use IMO syrup too, and I would rather you hear it from me than find it yourself. IMO syrup is fifth on our PB Cacao ingredient list. It is there for structure. Without it, we do not have a bar that holds together, travels, or tastes like something you want to eat twice. It has been generally recognized as safe since 2008, it is well tolerated at the amounts in a single bar, and I have no interest in pretending it is a villain. What it is not is our fiber. The 8 to 9 grams of Dietary Fiber on our panel come from chicory root fiber — the inulin that sits second on every one of our ingredient lists, ahead of the protein. We did not pad the number. We could not have, even if we wanted to. That is not marketing language. It is a consequence of how the panel is regulated, and it is verifiable by anyone willing to read two documents. Why 8 or 9 grams, and not 15 People ask this one more than I expected. If fiber is good and most of us are short, why not build a bar with twenty grams and close the whole gap in one bite? Because that is not how your gut works. Fermentable fiber is fermented. That is the entire point. But fermentation produces gas along with the short-chain fatty acids, and the amount your system handles comfortably at one sitting has a ceiling. Push past it and the experience stops being pleasant — bloating, pressure, the kind of afternoon that makes people swear off fiber entirely and go back to eating none. Eight to nine grams in a single serving sits near the practical upper end of what most people tolerate well in one sitting. It moves you roughly a third of the way to a daily target in one bar, which is meaningful, while leaving room for the fiber in your actual meals — where most of it should be coming from anyway. A bar is not supposed to replace vegetables. It is supposed to make the day you did not eat enough of them less of a loss. One honest heads-up If you are coming from a low-fiber diet — and statistically, most of us are — give your system a few days to adjust. Adding eight or nine grams at once to a gut that has not seen much fermentable fiber lately can feel like a lot at first. That is not a problem with the bar. It is your microbiome reorganizing around a new food supply. Start with one bar a day, drink water with it, and give it about a week. The adjustment is real, it is temporary, and it is worth sitting through. Fiber and protein are better together than either is alone In the last post I made the case for protein as the anchor nutrient for holding onto muscle as our bodies change. Fiber is the other half of that equation, and the two work differently enough that pairing them changes what a snack actually does. Protein is the most satiating of the three macronutrients — more filling, gram for gram, than either carbohydrate or fat. Fiber slows gastric emptying and blunts the speed at which glucose enters the bloodstream. Put them in the same serving and you get something that keeps you full and keeps the next two hours steady — rather than the rise and collapse that sends you back to the pantry at three in the afternoon looking for whatever is closest. This is the difference between a snack that interrupts your hunger and a snack that resolves it. Twelve grams of protein and nine grams of fiber in two hundred calories is not an accident of formulation. It is the specific combination that makes the calories do work. And it is why the total sugar line matters as much as the added sugar line — a point worth reading in full in Part 2 of this series, where we walk the whole panel line by line. What to actually look for If you take one practical thing from this post, make it this sequence. It takes about fifteen seconds in a store aisle.   Step What to do What you learn 1 Find the Dietary Fiber line on the panel The honest grams — legally limited to recognized fibers 2 Read the first five ingredients Where the bulk of the food actually comes from 3 Look for a named prebiotic fiber Chicory root, inulin, or another recognized fermentable fiber 4 Check where the syrups sit Structure ingredients near the top mean sweetness is doing the work 5 Compare fiber to protein A real food bar carries both; a candy bar carries neither   That is the whole method. It does not require a nutrition degree, and it does not require trusting anybody’s marketing — including ours. The quiet nutrient I spent most of my training life optimizing protein and barely thinking about fiber. I counted grams of one and ignored the other entirely, and I would not have told you there was a cost to that, because nobody was telling anyone there was. What changed my mind was not a headline. It was noticing, over and over in the research, that the nutrient nobody is marketing keeps showing up in the outcomes that actually matter — the barrier that holds, the inflammation that stays low, the decade that goes well instead of going sideways. Fiber is not exciting. It is not going to trend. But it is one of the clearest, cheapest, most under-used levers we have for aging the way we want to age, and almost all of us are leaving it on the table. You do not need a bar to fix that. Beans, oats, berries, artichokes, and a hundred other ordinary foods will do it better and cheaper than we can. But on the days when the vegetables did not happen and the afternoon is coming at you anyway, it matters what you reach for — and it matters whether the fiber on that label is doing anything once it gets where it is going. Ours is. Eight to nine grams of chicory root fiber. Twelve grams of plant protein. No added sugar. One bar, one habit, one thing off the list. Shop LAST Bars This post is part of the Resetting Normal Series. Read the full series: Part 1: Resetting Normal · Part 2: What’s Actually in Your Protein Bar · Part 3: Protein and Muscle as We Age · Part 4: Fiber, Your Gut, and Aging Well Here’s to aging well… Cheers! Joel J. Montesano Founder, Five Plus Protein References Miketinas D, et al. Usual dietary fiber intake among US adults with and without diabetes: NHANES 2013–2018. Presented at NUTRITION 2021 LIVE ONLINE, American Society for Nutrition. n = 14,640. U.S. Department of Agriculture, Agricultural Research Service. Fiber intake of the U.S. population: What We Eat in America, NHANES. FSRG Dietary Data Briefs. Giannouli V, et al. Gut microbiota and ageing: mechanisms, age-related diseases, and therapeutic perspectives. Healthcare. 2026;14(14):2117. Gopinath B, et al. Carbohydrate nutrition is associated with successful aging over 10 years. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. 2016. Blue Mountains Eye Study, n > 1,600 adults aged 50+. Dried chicory root improves bowel function, benefits intestinal microbial trophic chains and increases faecal and circulating short chain fatty acids in subjects at risk for type 2 diabetes. Gut Microbiome (Cambridge University Press). 2022. Randomized placebo-controlled trial, n = 55. U.S. Food and Drug Administration. FDA issues guidance, science review, and citizen petition responses on dietary fiber. June 14, 2018 — identifies inulin and inulin-type fructans among non-digestible carbohydrates meeting the dietary fiber definition. U.S. Food and Drug Administration. Responses to citizen petitions regarding isomaltooligosaccharide (IMO). January 13, 2020 — both petitions denied; evidence did not demonstrate a beneficial physiological effect in humans.