How to Double your Fiber – Dr. Mark Hyman

The Boring Nutrition Advice That Actually Works: How to Double Your Fiber Intake

If you had to guess the single most powerful piece of nutrition advice that people consistently ignore, “eat more fiber” probably wouldn’t come to mind. It sounds like the kind of thing you’d hear in a waiting room before a colonoscopy, not exactly inspiring. But according to Dr. Mark Hyman, it might be one of the most underrated levers for improving blood sugar, lowering inflammation, and reducing chronic disease risk, and most Americans aren’t getting nearly enough of it.

What fiber actually does in the body

Fiber is a type of carbohydrate found in plants that your body can’t fully digest, which is exactly why it’s so valuable. Unlike other carbs, it doesn’t break down into sugar and provides little to no calories, while still helping you feel full. That combination means you can feel more satisfied eating fewer calories overall, which is part of why people who eat more fiber tend to be leaner than those who don’t.

There are two types, soluble and insoluble, and while they work differently, most plant foods contain a mix of both, so there’s no need to obsess over which kind you’re eating. Together, fiber-rich foods can:

• Slow the absorption of sugar into the bloodstream, leading to steadier blood sugar and fewer energy crashes after meals
• Feed beneficial gut bacteria, which produce short-chain fatty acids like butyrate that help regulate inflammation and support gut barrier function
• Lower inflammation, with research linking higher fiber intake to lower levels of C-reactive protein, a key inflammation marker
• Decrease LDL cholesterol, an effect so well established that a University of Guelph study found adding just one cup of beans a day reduced LDL cholesterol by 8% in four weeks
• Improve overall nutrition, since fiber-rich foods like vegetables, legumes, fruits, nuts, and seeds naturally come packaged with magnesium, folate, potassium, and other beneficial nutrients

A quick caveat: fiber isn’t right for everyone, all the time

For most people, increasing fiber intake is one of the best things they can do for their health. But if you experience bloating, gas, or diarrhea after eating high-fiber foods, you’re not imagining it, and you’re not alone. These symptoms are common with conditions like IBS, SIBO, or sensitivities to certain fermentable carbohydrates known as FODMAPs.

The fix in these cases isn’t giving up on fiber permanently. It’s usually about healing the gut first, sometimes through a temporary reduction in foods like grains, beans, and raw produce, while focusing on clean proteins, healthy fats, and well-cooked vegetables that are easier to tolerate. Working with a practitioner familiar with gut health can help build a plan that supports healing without sacrificing overall nutrition.

The real target: 30 grams a day

A solid daily fiber goal is 30 grams or more, but the average American only gets about 17 grams a day. Rather than trying to hit 30 grams all at once, the simplest approach is aiming for 8 to 10 grams of fiber at every meal. Do that consistently, and you could add 10 to 15 grams a day just from meals alone, with snacks pushing that number up to 20 grams, effectively doubling most people’s current intake.

Here’s how to actually make that happen.

Strategy 1: Double up on non-starchy vegetables

Most nutrition advice tells you to watch portion sizes, but non-starchy vegetables are the exception. They’re low in calories, packed with nutrients, and high in fiber, so the goal here is to load up rather than hold back.

Aim for at least two servings of non-starchy vegetables at each meal, but redefine what a “serving” actually means. Forget the traditional half-cup measurement. Think of one full cup, about the size of your fist, as a single serving instead.

Some standout options include Brussels sprouts (6.4 grams cooked per cup), jicama (5.9 grams), broccoli (5.2 grams cooked), turnip greens (5 grams cooked), and kohlrabi (4.9 grams). Worth noting: cooked vegetables generally pack more fiber per cup than raw ones, simply because cooking shrinks their volume, letting more fit into the same space.

Strategy 2: Sneak in fiber-dense extras

Beyond vegetables, a handful of everyday foods can meaningfully boost your fiber intake without much effort:

• Avocado: half an avocado provides 5 grams of fiber and works with almost any meal
• Blackberries and raspberries: about 4 grams per half cup, easy to add to breakfast or snacks
• Chia seeds: just one teaspoon delivers 5 grams, and they blend easily into smoothies, salads, or puddings
• Beans: lentils, black beans, chickpeas, and lupini beans provide 5 to 9 grams per half-cup serving, though it’s smart to cap intake around a half-cup to one cup daily

Strategy 3: Round it out without overdoing it

A few additional sources can help close the gap, though they come with more starch or sugar, so moderation matters:

• Nuts and seeds: roughly 2 to 3 grams of fiber per ounce for almonds, pistachios, or sunflower seeds
• Fruit: about 2 to 3 grams per half-cup for most varieties
• Starchy vegetables: sweet potatoes, carrots, and winter squash offer 3 to 5 grams per half-cup, but shouldn’t be your primary fiber source
• Whole grains: intact grains like quinoa, black rice, and buckwheat provide modest amounts, around 2.5 grams per half-cup of cooked quinoa

The takeaway

The point here isn’t to hit a perfect number every single day. It’s simply having a target in mind at all. Once fiber becomes something you’re actually paying attention to, you naturally start experimenting with new foods, noticing what works for your body, and building habits that stick. Over time, eating more fiber stops feeling like a chore and starts feeling like second nature. Perfect isn’t the goal. Moving in the right direction is.

**Inspired by Dr. Mark Hyman’s Article on Fiber

This article is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment, and is not a substitute for a conversation with a qualified healthcare provider. Individual health needs vary. If you have questions about your health, we invite you to schedule a consultation with one of our providers.