One cup of chopped raw broccoli (about 91 grams) contains roughly 2.4 grams of dietary fiber, which covers about 8% of the daily value. That makes broccoli a solid but not exceptional source of fiber, comparable to most other cruciferous vegetables. Where it gets more interesting is in the type of fiber broccoli provides, which part of the plant you eat, and how cooking changes the picture.
Fiber in Raw vs. Cooked Broccoli
Raw and cooked broccoli deliver similar amounts of fiber, but the numbers shift slightly because cooking changes the volume of a cup. One cup of chopped raw broccoli weighs about 91 grams and provides around 2.4 grams of fiber. One cup of cooked, chopped broccoli packs in more plant matter by weight and bumps the fiber up to about 2.6 grams. The fiber itself isn’t being created by heat. You’re just fitting more broccoli into the same measuring cup once it softens and shrinks.
For a standard 2,000-calorie diet, the recommended daily fiber intake is about 28 grams. So a full cup of broccoli gets you roughly 9% of the way there. Two cups at dinner, mixed into a stir-fry or roasted on a sheet pan, and you’ve covered close to a fifth of your daily target from a single vegetable.
Soluble and Insoluble Fiber Breakdown
Broccoli contains both soluble and insoluble fiber, but the ratio depends heavily on whether you eat it raw or cooked. Raw broccoli is overwhelmingly insoluble fiber: about 3.06 grams per 100 grams of the vegetable compared to just 0.44 grams of soluble fiber. Cooking shifts that balance. Microwaved broccoli, for example, contains roughly 1.85 grams of soluble fiber and 2.81 grams of insoluble fiber per 100 grams, according to USDA data.
That distinction matters for your gut. Insoluble fiber adds bulk to stool and helps keep things moving through your digestive tract. Soluble fiber dissolves in water and forms a gel-like substance that slows digestion, helps regulate blood sugar, and feeds beneficial gut bacteria. The fact that cooking increases the available soluble fiber means your body may get more of that prebiotic benefit from steamed or microwaved broccoli than from raw florets.
Stems Have More Fiber Than Florets
If you’ve been tossing broccoli stems, you’re throwing away the most fiber-rich part of the vegetable. The stems contain noticeably more fiber than the florets, particularly insoluble fiber. This makes sense from a plant biology standpoint: stems provide structural support, so they’re built from tougher, more fibrous cell walls. They also contain more potassium and calcium than the florets.
The stems are perfectly edible. Peel the tough outer layer with a vegetable peeler, then slice or dice the tender interior. You can roast them alongside the florets, shred them into slaws, or add them to soups. Using the whole stalk instead of just the crown can meaningfully increase the fiber you get per head of broccoli.
How Cooking Method Affects Fiber
Fiber is more heat-stable than many other nutrients, so you won’t lose much regardless of how you cook broccoli. That said, there are small differences worth knowing about. A small percentage of soluble fiber can leach into cooking water during boiling, since soluble fiber dissolves in liquid. Insoluble fiber stays put. The longer you cook any vegetable, the more both types of fiber break down structurally, though they still count as dietary fiber in your body.
Steaming is generally considered the best method for preserving both fiber and other nutrients like vitamin C. Microwaving works similarly well. If you boil broccoli, keeping cook times short and using the cooking liquid in a sauce or soup can help you recapture whatever soluble fiber migrated into the water.
How Broccoli Compares to Similar Vegetables
Broccoli sits right in line with other cruciferous vegetables when it comes to fiber. One cup of chopped raw cauliflower (107 grams) has about 2.1 grams of fiber, also 8% of the daily value. Raw kale looks low at first glance, with only 0.66 grams per cup, but that’s because a cup of loosely packed kale leaves weighs just 16 grams. Per 100 grams, kale actually has comparable fiber density.
Broccoli won’t compete with fiber heavyweights like lentils (about 15 grams per cup cooked) or black beans (about 15 grams per cup). But vegetables play a different role in your overall fiber intake. They’re easy to add to nearly any meal, they come with very few calories, and you can eat large volumes without much effort. A couple of cups of broccoli alongside a grain and a legume can push a single meal well past 15 grams of fiber.
What Broccoli Fiber Does in Your Gut
Broccoli’s fiber feeds specific populations of beneficial gut bacteria. Research published in The Journal of Nutrition found that broccoli consumption increased microbial diversity in the gut and boosted the abundance of bacteria in the Lachnospiraceae family, a group associated with healthy gut function. More notably, bacteria in the gut responded to broccoli fiber by ramping up production of butyrate and acetate, two short-chain fatty acids that fuel the cells lining your colon and help regulate inflammation.
These effects showed up at intake levels equivalent to as little as a quarter cup to one cup per day in humans. The study also found that broccoli activated a signaling pathway in the gut lining involved in immune regulation. This pathway responds to compounds released during fiber fermentation and from broccoli-specific nutrients, suggesting that the fiber and the other bioactive compounds in broccoli work together rather than independently.