If you’ve had diverticulitis, you know how painful it is. And you’ve probably been told the solution is simple: eat more fiber.
You’ve done everything “right.” You’ve added whole grains, vegetables, and all the recommended foods to your diet. You track your fiber intake carefully. You avoid trigger foods.
But there’s something that works alongside fiber that’s arguably even more important for preventing flares, and almost nobody talks about it. Not your doctor, not the medical advice online, barely anyone.
And the crazy thing is, it’s so simple that when I tell you what it is, you might think it can’t possibly make that much difference. But I’ve seen it transform outcomes for our diverticulitis clients over and over again.
In this article, I’m going to reveal the missing prevention factor that works alongside fiber — and what you can actually do to prevent flares for good.
Here is a video we made, otherwise there is a written version underneath.
Problem: You’re Only Addressing Half the Equation
Let’s talk about the fiber approach you’ve already been following.
Maybe you’ve increased your whole-grain intake. Maybe you’ve added more vegetables, beans, and high-fiber foods to every meal. And here’s what happens:
For a while, things seem better. You’re doing what the doctors recommended. Your digestion improves somewhat. So you think: “Great! This is working. I’m preventing flares.”
But here’s the problem: Fiber alone is only half the equation. Without the second critical factor, fiber can actually backfire. And when you focus solely on fiber for months or years without addressing this missing piece, something dangerous happens: You’re creating harder stool that puts MORE pressure on your colon walls. You’re increasing friction instead of reducing it. Your diverticula pouches are under more stress, not less.
Think of it like this: You’re trying to push a dry sponge through a pipe. Without lubrication, that sponge creates friction, gets caught on edges, and puts pressure on the walls.
And now, when you eat high-fiber meals? They’re not moving through smoothly anymore — not because fiber is bad, but because you’re missing the critical component that makes fiber work properly.
For so many people, they end up wondering why they’re still getting flares despite doing everything “right.”
What’s Actually Missing?
The missing factor is hydration. Not just “drink more water” as throwaway advice, but understanding how proper hydration works with fiber to protect your colon.
Because the goal isn’t just to eat more fiber, it’s to create the optimal environment in your digestive tract so everything moves smoothly, without pressure, without friction, without triggering a flare.
Summary: Fiber alone is only half the equation for preventing diverticulitis flares. Without adequate hydration, fiber can actually create harder stool, increase friction, and put more pressure on your colon walls and diverticula pouches. The missing factor that makes fiber beneficial rather than harmful is proper hydration, which works together with fiber to create smooth movement through your digestive tract.
Why Hydration Matters More Than You Think
Most people never understand the actual mechanism of how diverticulitis develops — and therefore don’t realize why hydration is so critical.
Your doctor probably said, “Eat more fiber to prevent flares,” and sent you home. But they likely didn’t explain what’s actually happening in your colon that causes those diverticula pouches to become inflamed. So let’s take a deeper dive into what’s actually going on.
The Diverticulitis Process
Diverticulitis occurs when those small pouches or sacs — diverticula — in your colon wall become inflamed or infected. And what causes that?
According to scientific consensus, it’s when fecal matter, intestinal mucus, or other substances get trapped in these diverticula sacs. The thin walls become damaged, you get a perforation or puncture, and boom — infection, inflammation, pain.
Now here’s the key: If you think about the statistic that half or more than half of us will develop these diverticular sacs by age 60 just through the natural aging process, it’s not unusual that mucus and waste collect in these sacs at some point.
But they’re supposed to be naturally flushed out — gently, without damage. Just like waves gently washing sand out of a shell on the beach.
This natural flushing means symptoms don’t occur, and most people never even know they have diverticula in the first place. That’s why not everyone gets symptoms, right?
It’s Not Just About “Flushing”
So is it just as simple as “water flushes them out, so drink more water, and you won’t have another flare?” Not really. It’s much more fascinating and nuanced than that.
The only way to truly prevent flares is through understanding how hydration works at three different levels to protect your colon tissue, work with fiber, and reduce pressure.
And this is why many people stay stuck. They’re increasing fiber intake and hoping for the best, but never addressing the hydration component that makes fiber actually work.
This is why proper hydration education is so critical. It gives you the complete picture — then you can implement both strategies together instead of just doing half the work.
Summary: Most people don’t understand the mechanism behind diverticulitis — that it occurs when substances get trapped in diverticula pouches and cause inflammation. While these pouches should naturally flush out, proper hydration works at three critical levels to prevent flares: protecting colon tissue, working with fiber, and reducing pressure. Without understanding this complete picture, you’re only doing half the work needed for prevention.
How Water Actually Protects Against Diverticulitis
This is the piece most people miss entirely: Hydration doesn’t just “flush things out.” It works at three distinct levels to prevent flares.
Here’s what proper hydration actually does (you might know the first one, but I bet you won’t know points 2 and 3 — and they’re really important).
First: It Keeps Your Colon Tissue Elastic and Healthy
Our cells — including the cells in our colon walls where diverticula form — need water to remain hydrated, to remain as elastic and flexible as possible. This is even more important as we grow older.
When your colon tissue is well-hydrated, it’s more resilient. It can handle the normal pressure and movement of stool without tearing or creating weak spots that become diverticula.
When the tissue is dehydrated, it becomes more rigid, less elastic, and more prone to damage. Think about it:
- Why does your skin crack when it’s dry?
- Why do rubber bands snap when they’ve dried out?
- No other tissue in your body stays flexible when dehydrated
Second: Water Works With Fiber to Keep Everything “Slippery”
This is the part most people don’t understand and where there is such confusion around fiber and diverticulitis.
Fiber needs water to work properly and be beneficial to you. Without adequate fluids, fiber can actually harden stool and worsen inflammation risk, instead of helping it.
So let’s think about how fiber works. It’s a bit like a sponge that absorbs water into your colon to help keep everything sliding and flowing through, around all the turns and bends of your digestive tract, with minimal friction
Think of it like an oil pipe, where the contents are smooth and slippery. So if there are shapes or contours in the pipe, it doesn’t matter — everything slides by and doesn’t get caught up.
Because in the digestive tract, if anything gets caught up, it can tear the tissue, especially fragile tissue, like in a diverticula sac. When that gets torn, it gets inflamed, it gets infected. Boom — you have diverticulitis.
This is the critical connection between water and fiber that creates either a protective environment or a damaging one.
Third: Hydration Reduces Pressure in Your Colon
A lot of people think about what foods are going through them, but they don’t consider the velocity at which it moves through, and the influence of pressure in the digestive tract, and how impactful that is in diverticulitis.
Think of your colon as a balloon. With a deflated balloon, it’s limp. There’s no pressure on the walls because there’s no pressure inside the balloon. Blow the balloon up, with high pressure inside, it puts more force on the walls.
So there is more pressure on the walls of the colon, and many researchers now believe this increased pressure is what causes the diverticula to pop out and form in the first place.
The theory is then that proper hydration — combined with fiber — creates larger, softer stool volume that is easier to pass because it stimulates peristalsis — those wave-like muscle contractions that move everything through your gut.
We don’t consciously control that. The body just does it automatically, just like the heart pumps automatically. You don’t have to think about it.
So strong peristalsis means your colon doesn’t have to generate as much pressure to move things along. Less pressure equals less stress and potential damage to the colon wall and diverticula sacs, and therefore, in theory, a lower risk of a flare-up.
Summary: Proper hydration protects against diverticulitis at three critical levels: (1) keeping colon tissue elastic and resilient, (2) working with fiber to create a “slippery” environment that prevents friction and tearing, and (3) reducing colon pressure by stimulating natural peristalsis. Without adequate hydration, fiber can actually create harder stool and increase pressure, which is why strategic hydration alongside fiber intake is essential for preventing flares rather than inadvertently creating conditions that trigger them.
If you’re just getting started, download our free Low FODMAP food list to get clarity on common food triggers
Tap the blue button below to download our “Eat This, Not That” list, along with additional resources for Diverticulitis (it’s free!)
How Much Water Do You Actually Need?
Alright, so you understand why hydration matters. The obvious next question is: how much water should you actually be drinking?
There isn’t one perfect number — but there is an easy starting formula.
The Basic Formula
A simple rule of thumb is this: Aim for about half your body weight in ounces — or around 35 milliliters per kilogram — per day.
So if you weigh 180 pounds, that’s about 90 ounces, or roughly 2.7 liters. If you weigh 80 kilos, that’s about 2.8 liters per day. This is a baseline, not a hard rule.
When You Need More
If you exercise, sweat a lot, live in a hot climate, or eat a higher-fiber diet, you’ll likely need more.
A good adjustment is adding half a liter — or 16 ounces — for each hour of exercise or heavy sweating.
The Best Hydration Check
And here’s the hydration check I trust more than any calculator: your urine color.
- Pale yellow? You’re hydrated.
- Dark yellow? Drink more.
- Completely clear all day? You may actually be overdoing it.
This is the simplest, most reliable indicator of your hydration status without needing to track ounces obsessively.
The Fiber-Water Connection
Remember: For every 5 grams of fiber you add to your diet, drink an extra 8 ounces of water.
This ensures the fiber can do its job properly without creating the dry, hard stool that increases pressure and flare risk.
Summary: Aim for half your body weight in ounces (or 35ml per kilogram) of water daily as a baseline, adjusting for exercise, climate, and fiber intake. The most reliable hydration indicator is pale yellow urine — dark yellow means drink more, completely clear means you might be overdoing it. For every 5 grams of fiber added, increase water by 8 ounces to ensure fiber works beneficially.
The Strategic Hydration Approach
Now that you know how much water you need, here’s how we approach hydration with our diverticulitis clients to maximize prevention benefits:
1. Start Your Day with Water
Before you have your coffee or breakfast, drink a full glass of water. Your body has been without fluids for 8 hours or so, and starting with water sets the tone for the day.
This primes your digestive system and ensures your colon tissue starts the day properly hydrated.
2. Drink Consistently Throughout the Day
Don’t try to chug 2 liters all at once. Spread it out. Set reminders on your phone if you need to. Carry a reusable water bottle with you everywhere.
One of our clients who had been struggling with recurrent flares started carrying a 32-ounce bottle and made it a goal to refill it at least twice daily. Within weeks, she noticed significant improvement in her bowel regularity and overall symptoms.
Sounds simple, but oftentimes it’s the simple things we overlook.
3. Drink Extra Water When Increasing Fiber
If you’re following a protocol to gradually increase your fiber intake, you MUST increase your water intake at the same time.
A good rule of thumb: for every 5 grams of fiber you add, drink an extra 8 ounces of water.
And of course, you want to do this through the main part of your day, not necessarily late in the evening, because otherwise you’re going to have to wake up in the middle of the night multiple times to pee. So be a little bit savvy with when you drink your fluids.
4. Consider Your Drink Choices
Not all fluids are equal. Good choices include:
- Plain water (obviously)
- Herbal teas (non-caffeinated)
- Clear broths
- Coconut water (for electrolytes)
Moderate/Be mindful of:
- Coffee and tea (compensate with extra water)
- Juice (has some hydration benefit but can be high in sugar — I truly believe juice should be like a special occasion type drink, like the hotel breakfast on vacation or at a party. It’s not something that should just be part of your everyday routine.)
Avoid or severely limit:
- Alcohol
- Sugary sodas and energy drinks
- High-caffeine beverages in large amounts
Summary: Implement strategic hydration by starting each day with water before coffee or food, spreading intake consistently throughout the day using reminders or a tracking bottle, increasing water proportionally when adding fiber (8oz per 5g fiber), and choosing hydrating beverages wisely while limiting dehydrating drinks like alcohol and high-caffeine options.
What Should Your Next Steps Be?
If you’re feeling overwhelmed or struggling to manage your diverticulitis alone, professional guidance can make all the difference. We’ve helped over 15,000 people successfully navigate these exact challenges and implement prevention strategies that actually work.
To learn more about our integrated approach, I invite you to apply for a nutrition assessment call with us. We’ll help you make sense of what’s really happening and map out the next steps to get you feeling confident again — not just temporarily avoiding flares, but addressing the complete prevention picture for long-lasting peace of mind.
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