Same Calories, Fewer Absorbed: How Fiber Feeds the Gut Bacteria That Eat Your Calories
A controlled feeding study found that a high-fiber diet led to fewer calories absorbed per day, even when people consumed the same number of calories and macronutrients. The key is feeding your gut bacteria.
Welcome to the positive corner of the internet. We’re here to make your life healthier, happier, and less stressful. At the bottom of each email, we explain our editorial process, stance on AI, and partnership standards.
If you were forwarded this message, you can get the free daily email here.
Today’s Health Upgrade
Arnold’s Corner: Monday motivation
Eat this, burn 100-400 more calories per day
Does maximum strength determine brain age?
Workout of the week
Arnold’s Corner
Monday Motivation: I’m Going To Be Blunt
It’s Monday. For a lot of people, this is the day it all gets complicated again.
I love research and statistics. Since we added a few questions when people sign up for this newsletter, we’ve gotten hundreds of replies every week. The most common one, by far, is this:
“I’m confused about all the conflicting information about fitness, and I don’t know where to start.”
I’m going to be blunt with you. All of you already know enough to succeed.
Everyone already knows what healthy food is. The vegetables, the fruits, the lean proteins, the healthy fats. The real foods, not the treats. And let me be clear: we believe in treats. As a treat, not as the main menu.
Everyone knows they need resistance training. And everyone knows the basic movements. The squat. The pushup or the press. The row or the chin-up. The deadlift. We’ve got videos of them on our YouTube if you need a quick refresh.
Everyone knows it’s good to get outside, walk or ride a bike, and move a little.
Three simple things most people know.
And there isn’t one person who could try to do a little better at each of those things and not see results.
But still, people get stuck.
Instead of doing three sets of squats, they do ten sets of listening to podcasts about squats.
Instead of making a salad with some tuna or salmon, they read an influencer explaining the perfect human diet.
Instead of going for a walk and enjoying their life, they check every 10 steps to see if their watch says they are in Zone 2.
Here is where I get really blunt. It’s all bullshit.
I am a simplifier. My team can tell you.
Whether I am working on a new business deal or planning an event, I know the danger of getting into the weeds. The weeds are where you get stuck.
When we start to trip into the weeds, my whole team knows I’m about to say, “It’s all bullshit.”
It’s the same in everything.
Especially fitness.
Train. Eat real food, with a couple of delicious goodies once or twice a week. Get outside and move.
People are stuck because they haven’t learned what I have in 60 years in this industry.
It’s OK to be confused; it’s not OK to do nothing. You’re always going to be confused and feel like you don’t know anything if you always listen to the latest trends and experts.
The trick isn’t getting smarter. It is just doing what you know works and ignoring the noise.
Look at me. I’ve done OK, right?
I never listened to any of it. I showed up and did my workouts, even on the days I didn’t want to. I stuck to the basic movements. I didn’t learn anything fancy. I pushed every set past the comfort barrier, because that is where you grow.
I ate mostly protein, vegetables, fruit, and pasta, potatoes, and rice. I added protein shakes to hit my protein goal. And you better believe I eat a croissant or a piece of pie a couple of times a week.
I used to run. Now I ride my bike every day. I have always believed that moving outside does something special for the mind, not just the body, and science backs me up now.
I believe that thinking kills more transformations than trying and failing.
When they had six-minute abs, I ignored it.
When everybody started putting butter in their coffee, I ignored it.
When they talk about this peptide or that peptide, I ignore it.
So here is my simple solution for all of you.
Put the blinders on. The only thing you need to see is this: Train. Eat well. Move.
Once those three are a consistent part of your life, then we can talk about the next level.
Some people want my arm routine from 1974 on their very first day. They want to start by studying what I did at the peak of my bodybuilding career. And still, I have bad news for you: that training would bore most of you with the basics.
In all of these years, I’ve learned that people would rather read about the peak of a mountain than start climbing it themselves.
It’s why the program we are proudest of in our app is called The Foundation. It is not because it is for beginners. There is an intermediate option and an advanced one. These programs change you no matter who you are.
But we call it “The Foundation” because most people build their fitness on a pile of bullshit, and we want them to feel what it is like to train the basic movements the way that has worked for decades. Pushing every set just short of failure. Progressing the same movements week after week.
(For those of you who love the science, this is another area where it agrees with me. You need hard reps to grow. You need a program, not random workouts. And you need progression.)
And here is the part that ends the confusion. You do not have to choose any of it. We chose the movements. We built the progression. Your only job is to show up and press start.
That was our whole goal when we built an app in the first place. How do we let people just click start and stop all the thinking?
I believe that thinking kills more transformations than trying and failing. So I wanted people to be able to turn off their brains and see results, and they have. A lot of them tell me they just do the Foundation over and over because they love seeing progress without having to think.
It’s the whole goal of the information we share here for free every day too. You have probably noticed that most of our summaries of the latest trends come down to “you can ignore this.” And we bring the science to back it up.
Do you want the brutal truth? I think everyone knows this already, deep down.
The overthinking, the researching, and the confusion are really about fear. People have failed before, and they are afraid to commit and feel that again. Hunting for the perfect plan is just a way to put off the failure.
But you do not have to fail. I want you to succeed.
I see this even with some of the people who join us in the app. They set everything up, and then they sit there staring at workout one, never pressing start. The tools are right in front of them. The fear is just louder.
So this is my push, whether you train with us or on your own.
You do not need a scientifically engineered twenty-point daily protocol. (No wonder you are confused.)
Just do something. Do the squats. Make the real meal. Take the walk.
Or if you want the choosing done for you, that is exactly what the Pump Club app is for. Open it and press start.
Whatever you do, this week, the goal is simple.
You are going to stop getting pulled into the weeds.
You know what to do.
This week, you start doing it.
Now hit reply and tell us the one thing you are going to start this week. Not next Monday. This one.
Together With Momentous
The Nutrient That “Burns” More Calories
Our job is to bust myths and misconceptions. And we’ve been clear for 3 years that fat burners don’t work.
But research suggests there might be a real exception to the rule. Forget all the energy pills because this one comes from food.
Scientists discovered something that should make you like fiber a lot more: eat enough of it, and the bacteria in your gut will eat some of your calories for you.
In a tightly controlled study, researchers fed healthy adults two diets with identical calories and identical macros. The only real difference was the details of what people ate.
For example, both diets would have the same amount of carbohydrates, but one included high-fiber whole foods (think fiber, resistant starch, and minimally processed ingredients), and the other mimicked a typical Western diet.
Same calories in. But, once the data was reviewed, the scientists found that the change in food led to a different amount of calories absorbed.
On the whole-food, high-fiber diet, participants “burned” an extra 116 calories through their stool without feeling any hungrier. And that was the average. Some people passed close to 400 calories a day.
This wasn't just fiber passing through undigested. Feeding your gut microbes more fiber grew their population (think about good bacteria colonizing), and those bacteria consumed some of the meal's energy before it would stick to your body.
Put simply, more fiber led to more good bacteria, and that good bacteria feasted on the calories you consumed, leaving less to be stored on your body.
Unlike most diet advice, which is about removing food, this was about what you add.
Most people eat only about half the fiber they should, so there's room to grow. Load up on vegetables, fruit, legumes, oats, and whole grains.
If you need help getting more fiber, that’s why we developed Fiber+ with Momentous.
We invested two years developing a formula that makes a real difference in gut health: 3 sources of fiber, 6 grams per serving, a mix of soluble, insoluble, and resistant starch. Everything you need to feed your healthy bacteria without bloating or stomach discomfort. It’s the first product ever developed by the Pump Club, and has Arnold’s seal of approval.
As an APC reader, get 35% off your first purchase subscription or 14% off a one-time order. Unlike many supplements, Fiber+ is backed by research, and you will notice a difference within the first week. And if you pick up a container at The Vitamin Shoppe, you’re entered into a chance to win a workout with Arnold.
But remember, the benefits are in the dose. Aim for at least 25 grams per day and try to build up to about 40 grams daily.
Longevity
Your Brain Doesn't Care About Your One-Rep Max
Somewhere along the way, fitness advice picked up a rule nobody voted on: if you're maxing out your weights, it doesn’t matter.
So if you’re not frequently testing your 1-rep max, you could talk yourself into doing nothing at all.
However, a new study found that resistance training is restorative for your brain and body. And as long as you push intensity — and there are many ways to do that without maxing out on weight — it’s good news for your body.
When older adults lifted for two years, their brains looked younger on scans, and it barely mattered whether they trained with heavy or light weights.
Researchers randomly assigned older adults over the age of 60 to heavy resistance training, a moderate routine (one supervised session plus two at home each week), or no exercise. Brain scans came at the start, one year, and two years. A "brain-age clock," a model built on scans, estimated how old each brain looked.
Both lifting groups lowered their brain-age gap over two years. The non-exercisers didn’t see any positive changes. But that wasn’t all the researchers found.
The heavy and moderate group saw brain age improve about 2 years. And when researchers asked whether the load used (heavier or lighter) explained the brain change, the link basically vanished.
So the brain wasn't paying out in proportion to the weight on the bar.
Pushing hard with the weight being used and staying consistent is what led to a younger-looking brain, not the load.
Nobody's cognition was measured, so it’s just evidence that steady training may slow one sign of brain aging. If you want to make sure your workouts make a difference, the routine studied included at least three sessions per week.
Workout Of The Week
The 1-2-3-4 Ladder
This is a session that ties everything together we’ve been sharing for the past month.
After a warm-up, you start with the highest intensity you can maintain for one minute. After equal rest, slightly reduce the intensity and push to 2 minutes of work followed by 2 minutes of recovery. You keep adding time and rest for the next two sets.
It's a fun and challenging way to touch every gear you've trained, and the built-in progression keeps you honest.
The Workout
Warm up: 10 min to get your blood flowing and prepare for a high-intensity set. But the warm-up should not be exhausting.
The Work (equal recovery after each interval):
Set 1: 1 minute all-out sprint + 1 minute rest
Set 2: 2 minutes very hard + 2 minutes rest
Set 3: 3 minutes hard + 3 minutes easy
Set 4: 4 minutes moderate intensity (your 4×4 pace)
Cool down: 4-5 minutes
Pick your tool
Rower
Ski Erg
Kettlebell swings
Sled push and pull
Hill running or sprints
Give it a try, and start your week strong!
Better Today
Take any of these tips from today’s email and put them into action:
1. Arnold Schwarzenegger On Fitness Trends: It’s All BS
What's Arnold's approach to training and nutrition? Stop overthinking and avoiding fundamental truths you already know. Arnold believes it’s best to master three basics before anything else — resistance-train the fundamental movements, eat mostly whole foods with an occasional treat, and move outside daily. Other than those habits, ignore everything else until those are consistent.
Why it matters: Chasing every new trend keeps you stuck and scared to start.
Try this: Pick one thing — a workout, a real meal, or a walk — and do it today. If you want to think less and just act, we have you covered with the Pump Club app (free 7-day trial included).
2. Your Gut Bacteria Eat Some of Your Calories (If You Feed Them Fiber)
Feeding your gut microbes more fiber makes them consume some of your meal's energy before your body can store it, so a high-fiber whole-food diet left people absorbing about 116 fewer calories a day at identical calorie and macronutrient intake.
Why it matters: Eating more fiber lets your gut bacteria burn off some of your calories for you. Same food, same calories — but you keep fewer of them.
Try this: Add a serving of beans, veggies, or whole grains to one meal a day. If you need help, Fiber+ was developed to provide three sources of fiber to improve your gut health.
3. Lifting Made Older Brains Look 2 Years Younger
In a randomized trial, older adults who resistance-trained showed brains that measured roughly 2 years younger on scans, and the effect held whether they trained with heavy or moderate loads — so effort and consistency, not the load, drove it.
Why it matters: Resistance training supports a healthier, younger brain, whether the weights are heavy or light.
Try this: Prioritize at least three strength workouts each week. Push hard, skip the ego lifting, and be consistent.
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 by “Together With”). Why? Because it allows us to keep the APC emails 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.
—
Publisher: Arnold Schwarzenegger
Editors-in-chief: Adam Bornstein and Daniel Ketchell