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Today’s Health Upgrade
The one diet change almost everyone overlooks
A note from Arnold
Let’s analyze a popular headline (about dementia prevention)
Can you reduce your brain age?
Health
The Simplest Diet Change That Could Add Years to Your Life
Most nutrition advice asks you to subtract something. Cut carbs, drop calories, eliminate this food, avoid that one. What if the most powerful thing you could do was just add more of one thing to your diet?
In one of the largest studies we’ve ever seen (and we’ve covered thousands), scientists found that eating more fiber meaningfully reduced your risk of heart disease, stroke, type 2 diabetes, and colorectal cancer.
In other words, in an industry filled with too much hype, fiber might be one of the highest-leverage dietary habits identified in nutritional science.
Researchers analyzed 185 prospective studies and 58 clinical trials representing approximately 135 million person-years of data, which is about as close to definitive as nutrition science ever gets.
Compared to people eating the least fiber, those eating the most saw 15 to 30 percent lower rates of all-cause and cardiovascular mortality, plus significantly lower rates of the types of disease that pose the greatest threat to longevity.
Clinical trials found that higher fiber intake also led to lower body weight, blood pressure, and total cholesterol. But it wasn’t just about eating fiber; there appears to be a clear threshold where you unlock the benefits.
Health improvements kick into high gear when you reach 30 grams per day, with the potential for even greater benefits beyond that.
At a minimum, you want about 25 grams per day. Unfortunately, the average American currently eats around 15 grams.
Even more staggering, data suggests that 95 percent of Americans don’t get enough fiber.
Fiber does several things at once. It slows digestion, which blunts blood sugar spikes. It binds to cholesterol and helps remove it from circulation. It feeds the gut bacteria that regulate inflammation, immunity, and metabolic function. The researchers used unusually strong language for a nutrition paper, describing the relationship to disease as potentially causal rather than merely associated.
You don't need a dramatic diet overhaul to close the gap. A cup of lentils and a whole avocado are both loaded with fiber. Add an apple and a handful of almonds to your current routine, and you're getting more than the average person. Toss in a bowl of oatmeal and green veggies, and you’re there. But don’t let those options intimidate you. Pick one high-fiber food you actually enjoy and start there, and the rest gets easier. Or, if you need help, we developed something special to help close the fiber gap.
Together With Momentous
A Note From Arnold: We Did Something About The Fiber Gap
I've spent 60 years in fitness. I've watched this industry sell people everything from exotic superfoods and random ingredients with names nobody can pronounce, to supplements that change every three years when the trend shifts.
We just talked about it yesterday. How many of you have wasted money on detox teas, testosterone boosters, or fat loss supplements?
I get it, their marketing makes me think sometimes, and I’ve seen it all.
Meanwhile, the most powerful dietary intervention in nutritional science has been sitting there the whole time, with too much data to ignore.
Fiber matters. It’s real health, longevity, gut health, and heart protection. But it’s boring. No one posts about it.
That bothered me. So we decided to do something about it. And that’s why we spent the last two years building Fiber+.
I wanted something that actually changed your gut — not just today, but over time.
Most fiber supplements give you one source of fiber. It’s sludge. It forms a gel, slows digestion, and keeps you regular. Don’t get me wrong, that is fantastic and important, and I know many people feel less bloated and more comfortable because of the sludge.
But it doesn't feed your gut bacteria in a way that actually transforms your microbiome.
When we partnered with Momentous to create Fiber+, I told them I only wanted to do this if we did it right. Not a basic powder in a new container. Not a product that moves things through your gut and calls it a day.
For that, you need resistant starch. It’s something we first wrote about in this newsletter years ago, not long after we started, and I immediately asked Adam to look into it more.
Resistant starch is the ingredient that most fiber products are missing. It directly feeds your good gut bacteria. They eat it. And when they do, they produce the compound that feeds your microbiome. I’m not the science guy, but Adam says it drives the kind of inflammation reduction and metabolic improvements that show up in your cholesterol, blood sugar, and energy.
Fiber+ uses three distinct fiber sources. Psyllium for immediate results you can feel — the sludge, as I call it. Resistant starch (Solnul™) to transform your microbiome. Rice bran hull for long-term protection. They work on different timelines and do different jobs, so you don’t just take away bloating and stay regular. You're actually rebuilding your gut ecosystem from the inside out.
No artificial sweeteners. No artificial flavors. No orange flavor. 6 grams of fiber per serving.
If you're already taking probiotics, keep taking them. But understand what you're missing without fiber: you're importing healthy bacteria and giving them nothing to eat. Fiber is what keeps them alive after they arrive. Think of it as soil for everything already working inside you. You wouldn’t plant flowers without soil.
The article above showed you the research. 135 million person-years of data. 15 to 30 percent lower risk of dying from any cause. Lower rates of the diseases that matter most.
We built Fiber+ to make that research real for you in a formula that does more than any single-source fiber on the market, at a dose that matters, with ingredients you can actually trust. And with a taste you’ll actually enjoy.
Try Fiber+ today. We built it for you because we know your gut, and the rest of your body, will thank you.
Beyond The Headline
“Brain Training Reduces Dementia By 25%”
If you've seen headlines claiming that a brain training app can cut your Alzheimer's risk by 25 percent, you're not wrong to be curious. You're also not wrong to be skeptical.
Staying mentally active, especially with tasks that challenge your processing speed, might support brain health as you age. But the claims are not as extreme as what you might see in the news.
The latest headline comes from one of the longest cognitive training studies. Nearly 2,800 adults aged 65 and older were randomly assigned to one of four groups: memory training, reasoning training, speed-of-processing training, or no training. Each program lasted just 10 sessions over five to six weeks, and some participants received booster sessions at 11 and 35 months. Researchers then tracked dementia diagnoses through Medicare records for 20 years.
When researchers compared each training group to the control group, none of the programs significantly reduced dementia risk. And yet, the headlines will tell you that games led to a 25 percent reduction in dementia.
So is the stat made up? Not exactly.
That positive result only appeared when they looked specifically at speed-training participants who also completed booster sessions. That's a subgroup of a subgroup, and the researchers didn't adjust for multiple comparisons, which increases the risk of a false positive.
There's also a selection problem. Booster sessions were offered only to participants who completed most of the initial training, which likely means they were already healthier or more motivated than the average person in the control group.
So what actually holds up for protecting your brain? The most powerful boosters are exercise, particularly resistance training and aerobic activity. Managing blood pressure and cholesterol, prioritizing sleep, and maintaining real social connections all matter, too.
Health
The Workout That May Keep Your Brain 2 Years Younger
If you’re worried about the item you just read, turns out, you can pump up your mind the same way you pump up your muscles.
A two-year randomized trial found that both moderate and heavy resistance training reduced biological brain age by about 2 years compared to people who didn't exercise.
Researchers used "brain aging clocks" to estimate how old your brain looks based on its connectivity patterns. They tracked participants across two years, randomly assigned to heavy resistance training, moderate resistance training, or a non-exercise control group.
At the end of the study, both lifting groups showed measurably younger brains. Heavy resistance training specifically increased connectivity in the region most linked to focus, decision-making, and executive function.
One thing worth saying clearly: this study measured a brain imaging biomarker, not direct cognitive performance. "Two years younger on an fMRI" is not the same as a confirmed reduction in dementia risk — that research still needs to happen. But brain aging clocks are a promising tool, and the findings align with a growing body of evidence showing resistance training supports cognitive health after 40.
The most encouraging detail? Even if you can’t push maximum weight, moderate intensity produced significant effects, too.
If you're already lifting, keep going. If you're not, this is a good reason to start. Even two full-body sessions a week of moderate resistance training puts you within the range studied by this research. The minimum effective dose here is lower than most people assume, and the upside extends well beyond what you can see in the mirror.
Better Today
Take any of these tips from today’s email and put them into action:
1. Eating More Fiber Cuts Your Risk of Dying Early by Up to 30%, According to 135 Million Person-Years of Data
An analysis of 185 prospective studies and 58 clinical trials, representing approximately 135 million person-years of data, found that people eating the most dietary fiber had 15 to 30 percent lower rates of all-cause and cardiovascular mortality compared to those eating the least — with the strongest benefits beginning at 25 to 30 grams per day, a threshold most Americans never reach (the current average is 15 grams). The fiber-disease relationship was described by researchers using unusually strong language for a nutrition paper: potentially causal, not merely associated. The average American is 10 to 15 grams short of meaningful protection — close enough that adding lentils, an apple, and a handful of almonds, and a multi-source fiber supplement to your current diet could close most of the gap today.
2. Most Fiber Supplements Give You One Source. Here's Why That's Not Enough — And What Resistant Starch Actually Does to Your Gut
Fiber+ combines three distinct fiber sources — psyllium husk for immediate digestive relief, resistant starch to directly feed beneficial gut bacteria and drive microbiome transformation, and rice bran hull for long-term protection — delivering 6 grams of fiber per serving with no artificial sweeteners or flavors. Unlike single-source fiber supplements that address regularity but leave your microbiome unchanged, resistant starch is fermented by gut bacteria into short-chain fatty acids, which are linked to reduced inflammation, improved blood sugar regulation, and metabolic health benefits. Arnold built Fiber+ with Momentous because the 135 million person-years of fiber research is only actionable if the product actually closes the microbiome gap — and most products on the market don't.
3. A 20-Year Study Followed Nearly 2,800 Older Adults. The Brain Training Programs Did Not Reduce Dementia Risk As Much As Headlines Suggest
A 20-year randomized trial of adults aged 65 and older found that none of the three brain training programs — memory, reasoning, or speed-of-processing — significantly reduced dementia risk compared to controls when analyzed as intended; the widely-cited “25% reduction in dementia” figure came exclusively from speed-training participants who also completed optional booster sessions, a subgroup analysis conducted without adjustment for multiple comparisons, substantially increasing the risk of a false positive. The booster group selection bias — sessions were offered only to participants who completed most of the initial training, likely healthier and more motivated than average — further undermines the headline claim. Keeping your brain sharp is a good idea, but the data didn’t support the claims. What actually holds up for brain protection research: resistance training, aerobic exercise, blood pressure and cholesterol management, sleep quality, and social connection.
4. Resistance Training Reduced Biological Brain Age by 2 Years in a Randomized Trial (And Moderate Intensity Lifting Works Too)
A two-year randomized controlled trial found that both moderate and heavy resistance training reduced biological brain age by approximately 2 years compared to a non-exercise control group, with heavy resistance training specifically increasing connectivity in prefrontal regions governing focus, decision-making, and executive function. Researchers used brain aging clocks that were tracked over two years of structured training. Two full-body resistance training sessions per week at moderate intensity produced significant effects, placing the minimum effective dose well within reach for most people — and the benefits extend to brain regions that decline most predictably with age.
The Positive Corner of The Internet
About Arnold’s Pump Club Editorial Standards
We do things a bit differently here, starting with transparency.
The Content: All APC emails are researched, written, and fact-checked by the APC editors (see bottom of the email), with written contributions from Arnold (noted with “Arnold’s Corner”). Links take you to original studies (not second-hand sources).
Does AI play a role? Not for the primary content, but it is used in two ways. The main items are original content written by the APC team. The summaries at the end are AI-generated based on the human-written content above. We also use an AI tool to review our interpretations of the research and ensure scientific accuracy. We don’t assume AI is right, but we use technology to hold ourselves accountable.
Yes, we have partners (all clearly noted). Why? Because it allows these emails to remain free. We first test products, and then reach out to potential partners who offer ways to help you improve every day. The bar is set high, and to date, we have turned down millions in ad deals. (Example: we will not partner with any non-certified supplements or those without evidence in human trials). If we won’t buy the product, we won’t recommend it to you. And if there’s no evidence it works, then there’s no place for it here.
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Publisher: Arnold Schwarzenegger
Editors-in-chief: Adam Bornstein and Daniel Ketchell
