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How to Double Your Fiber Intake

July 28, 2025

What’s the most powerful nutrition advice that most people ignore?

Hint: It’s the kind of boring advice you might see while waiting for a colonoscopy. (Which partly explains why most people ignore it.) 

The answer: “Eat more fiber.”

Exciting? Nope.
Powerful? Absolutely. 

Adding 10 to 20 grams a day can significantly improve your blood sugar, lower inflammation, and reduce your risk of chronic disease. 

It can also shift your entire diet in a healthier direction—filling you up with real food and crowding out the stuff that’s dragging you down. 

And most Americans aren’t getting nearly enough.

Can you add 10 grams of fiber a day to start?
Or maybe the better question: Can you afford not to?*

I’ll show you how—in three easy steps. 

* For some people—including those with gut issues or autoimmune conditions—more fiber isn’t always better. We’ll talk about when it might be a problem, and what to do instead.

The “Magic” of Fiber 

Before we get to the how, a quick primer to give you a little more inspiration. 

In case you didn’t know, fiber is a type of carbohydrate found in plants that your body can’t fully digest. Because of this, scientists refer to it as a “non-digestible carbohydrate.” That’s a good thing.

Unlike other carbs, fiber doesn’t break down into sugar and provides little to no calories. At the same time, it also helps fill you up. 

The result: By increasing your fiber intake, you can feel more satisfied on fewer calories—one reason why people who consume more fiber are often leaner than those who eat less.^1,2,3

Put another way: Eat more fiber, crave less junk. It’s not magic, but if you significantly increase your fiber intake, it might seem like it is. 

That’s not the only benefit fiber has on your health, though.

More Benefits of Fiber

There are two types of fiber—soluble and insoluble—and they offer different benefits. Soluble fiber helps slow digestion and steady blood sugar. 

Insoluble fiber adds bulk and keeps things moving through your digestive tract.

But most plant foods contain a mix of both, so there’s no need to micromanage which kind you’re getting.

In general, increasing your fiber intake can:

• Slow the absorption of sugar into your bloodstream. Fiber, especially the soluble kind, slows the rate at which carbohydrates are digested and absorbed. That means steadier blood sugar and fewer spikes and crashes after meals.
  
  
• Feed your gut microbes. Fiber is often called a “prebiotic” because it feeds the beneficial bacteria in your gut. More technically, scientists refer to fiber as a “microbiota-accessible carbohydrate”—your body can’t digest it, but your microbes can.⁴ In the process, they produce short-chain fatty acids like butyrate, which help regulate inflammation, support gut barrier function, and even influence metabolism.
  
  
• Lower inflammation. Research shows that people who eat more fiber tend to have lower levels of C-reactive protein (CRP), a blood marker of inflammation.⁵ This may be due to the fiber itself, the healthful nutrients in fiber-rich foods, or its beneficial effects on blood sugar, weight, and gut health. Or most likely, all of the above.
  
  
• Decrease LDL cholesterol. You’ve probably heard this before, as it’s a well-established finding.⁶ But here’s a recent example: A University of Guelph study found that adding 1 cup of beans—they ate black, navy, pinto, dark red kidney, and white kidney—reduced LDL cholesterol by 8 percent in four weeks.⁷ That’s the equivalent of about 15 to 18 additional grams of fiber a day. 
  
  
• Improve your overall nutrition. Fiber-rich foods—like vegetables, legumes, fruits, nuts, and seeds—come packaged with antioxidants, vitamins, and minerals. Think magnesium, folate, potassium, and polyphenols. So you’re not just getting fiber; you’re getting a better nutrient profile overall.

How to Double Your Fiber Intake

A good daily goal for fiber: Eat 30 grams or more a day. But turns out, most folks aren’t even close to this number. The average American consumes just 17 grams of fiber per day, according to the British Medical Journal.⁸

Of course, for many, getting to that 30-gram level can feel pretty daunting. That’s where having a clear and doable plan comes in. 

My advice: Shoot for 8-10 grams of fiber at every meal. 

If you’re already there, great. You’re way better than average! 

But if your intake is closer to the norm, this shift alone could give you an additional 10 to 15 grams of fiber a day. 

Include fiber in one or two snacks (if you have them), and you might boost your daily intake by up to 20 grams—potentially doubling what you’re consuming now.

Here are three strategies for making that happen. 

Strategy #1: Have a double serving of non-starchy vegetables. 

Most nutrition advice tells you to watch your portions. But when it comes to non-starchy, high-fiber vegetables, you want to do the opposite.

After all, they’re low in calories, high in nutrients, and rich in fiber. So don’t restrict—load up. 

Whenever you have non-starchy vegetables—aim to include them at each meal—shoot for a minimum of two servings.

But here’s the catch: Skip the conventional serving sizes. 

Traditionally, a serving of vegetables is defined as a half-cup. From now on, think of one serving as one full cup. For a visual, that’s about the size of your fist. 

If you only focus on this step, you’ll likely be amazed at how much it reduces your cravings and improves your overall eating habits.

Below is a short list of non-starchy vegetables you can choose liberally from, along with the amount of fiber in one cup. (Note: Cooked vegetables contain more  fiber than raw, simply because cooking shrinks them down. That means more vegetable—and more fiber—fits in the same space.) 

Fiber in Non-Starchy Vegetables 

Strategy #2: Use these foods to sneak more fiber into your day.

In addition to vegetables, these fiber-rich foods can help you quickly boost your intake—and they’re easy to work into your everyday routine.

• Avocado: a half avocado provides 5 grams of fiber and is a delicious addition to just about any meal. It’s great with eggs, in a salad, or as a complementary side.
  
  
• Blackberries and raspberries: Both contain about 4 grams of fiber per half cup, which you could have every day, as part of any snack or meal.
  
  
• Chia seeds: Just one teaspoon of these crunchy, slightly nutty-tasting seeds contains 5 grams of fiber. And you can add them to almost anything—salads, smoothies, stir fry. You can even create a dish around them, using these fiber-packed recipes: coconut chia pudding (15 g fiber); super simple chia seed pudding (13 g fiber); vanilla blueberry chia seed pudding (25 g fiber); warm chia pear porridge (10 g fiber).
  
  
• Beans. As you probably already know, beans are loaded with fiber. But don’t overdo it. Limit to a half-cup to 1 cup a day, particularly of lentils, black beans, garbanzo beans (chick peas), or lupini beans. A half-cup serving of beans will provide anywhere from 5 to 9 grams of fiber, depending on the variety. 

Strategy #3: Include other fiber sources—without overdoing it.

Vegetables, seeds, berries, and beans are some of the most effective ways to boost your fiber intake—but they’re not the only ones. Other plant foods can contribute as well. 

Just keep in mind that some of these come with more starch, sugar, or calories, so it’s best to include them in moderation.

• Nuts and seeds: A small handful (about 1 ounce) of almonds, pistachios, or sunflower seeds offers 2–3 grams of fiber. Walnuts and pumpkin seeds contain a bit less—closer to 1.5 to 2 grams. They’re a great addition, but stick to 1 to 2 handfuls a day as they can be easy to overeat. 
  
  
• Fruit: Besides blackberries and raspberries, most fruits provide about 2 to 3 grams of fiber per half-cup. 
  
  
• Starchy vegetables: Cooked sweet potatoes, carrots, winter squash, and parsnips contain about 3 to 5 grams of fiber per half-cup. These are real, nutrient-rich foods—but again, don’t rely on them as your primary fiber source as they’re also high in starch.
  
  
• Whole grains: Most packaged “whole grain” products aren’t truly whole. But intact grains like quinoa, black rice, buckwheat, and amaranth can be good sources of fiber if tolerated. For example, a half-cup of cooked quinoa has about 2.5 grams of fiber.

Look for opportunities.

Let’s be clear: The most important thing here isn’t to hit a perfect fiber number every single day. It’s about having a target in the first place.  

Once you set an intention to eat more fiber, you’ll get better at making it a bigger part of your meals. 

You’ll be more open to trying new foods, more curious about what works for your body, and more likely to stick with it. 

Over time, you’ll find fiber-rich foods you actually enjoy, and eating more of them will feel easy and natural.

Remember: You don’t have to be perfect. You just need to get moving in the right direction.

References

1. Slavin JL. Position of the American Dietetic Association: health implications of dietary fiber. J Am Diet Assoc. 2008 Oct;108(10):1716–31. 

2. Tucker LA, Thomas KS. Increasing total fiber intake reduces risk of weight and fat gains in women. J Nutr. 2009 Mar;139(3):576–81. 

3. Howarth NC, Saltzman E, Roberts SB. Dietary fiber and weight regulation. Nutr Rev. 2001 May;59(5):129–39. 

4. Slavin J. Fiber and prebiotics: mechanisms and health benefits. Nutrients. 2013 Apr 22;5(4):1417–35.

5. Ma Y, Griffith JA, Chasan-Taber L, Olendzki BC, Jackson E, Stanek EJ 3rd, et al. Association between dietary fiber and serum C-reactive protein. Am J Clin Nutr. 2006 Apr;83(4):760–6.

6. Brown L, Rosner B, Willett WW, Sacks FM. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Am J Clin Nutr. 1999 Jan;69(1):30–42. 

7. Doma KM, Dolinar KF, Dan Ramdath D, Wolever TMS, Duncan AM. Canned Beans Decrease Serum Total and LDL Cholesterol in Adults with Elevated LDL Cholesterol in a 4-wk Multicenter, Randomized, Crossover Study. J Nutr. 2021 Dec 3;151(12):3701–9.

8. McKeown NM, Fahey GC Jr, Slavin J, van der Kamp JW. Fiber intake for optimal health: how can healthcare professionals support people to reach dietary recommendations? BMJ. 2022 Jul 20;378:e054370.