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Does raw broccoli cause more gas than cooked?

Broccoli is a nutritious vegetable that is rich in fiber, vitamins, minerals, and antioxidants. However, some people find that eating broccoli, especially raw broccoli, makes them gassy and bloated. In this article, we’ll explore whether raw broccoli causes more gas than cooked broccoli.

The Fiber Content of Raw vs Cooked Broccoli

One of the main reasons broccoli causes gas is because of its high fiber content. Fiber is indigestible by human enzymes, so it passes through the digestive system to the large intestine where it is fermented by gut bacteria. This fermentation process produces gas as a byproduct.

There are two main types of fiber in broccoli:

  • Soluble fiber – dissolves in water to form a gel-like material
  • Insoluble fiber – does not dissolve in water, passes through the digestive system intact

Raw broccoli contains more insoluble fiber than cooked broccoli. One study found that 100g of raw broccoli contains 2.6g of insoluble fiber, while 100g of cooked broccoli contains 2g.[1] The cooking process softens the insoluble fiber in broccoli, making it easier to break down and less likely to cause gas.

However, cooking broccoli also destroys some of the soluble fiber. 100g of raw broccoli has 2.4g of soluble fiber, compared to 1.3g in cooked.[1] Even though soluble fiber dissolves in water, it can still cause gas because of the way gut bacteria ferment it.

Overall, raw broccoli has more total fiber than cooked broccoli, which likely contributes to it causing more gas for some people.

Broccoli Type Insoluble Fiber (g) Soluble Fiber (g) Total Fiber (g)
Raw 2.6 2.4 5.0
Cooked 2.0 1.3 3.3

Other Factors That Contribute to Gas

While fiber content plays a major role, there are other factors that can contribute to raw broccoli causing more gas than cooked broccoli for some people.

Sulfur-Containing Compounds

Broccoli contains sulfur-containing compounds like sulforaphane and allyl isothiocyanate. These compounds give broccoli its sometimes pungent smell and taste.

Cooking broccoli reduces the levels of these sulfur-rich compounds because they leach out into the cooking water or get destroyed by heat. One study found that boiling broccoli for 6 minutes reduced its sulforaphane content by 19-59%, depending on the specific cultivar.[2]

For some individuals, the remaining sulfur compounds in raw broccoli may contribute to more gas and bloating when eaten.


FODMAPs (fermentable oligo-, di-, monosaccharides and polyols) are short chain carbohydrates that can be hard to digest. Like fiber, FODMAPs are fermented by gut bacteria, which results in gas production.

Raw broccoli contains higher levels of the FODMAP fructan than cooked broccoli. One study found that cooking broccoli by boiling or steaming helps reduce fructans by leaching them into the cooking water.[3]

The higher fructan content in raw broccoli may exacerbate gas and bloating in people who are sensitive to FODMAPs.


Raffinose is a complex sugar that humans lack the enzyme to digest. It is found naturally in broccoli and other cruciferous vegetables.

One study showed that simmering broccoli in water for just 2.5 minutes decreased its raffinose content by 59%.[4] The intact raffinose in raw broccoli passes to the colon where gut bacteria ferment it and release gas.

Speed of Digestion

The speed at which food passes through the digestive system can also impact gas levels. Slower transit time allows for more microbial fermentation of fiber, FODMAPs and other compounds in the colon.

Chewing raw broccoli very thoroughly can help speed its passage and reduce gas. But in general, the fibrous texture of raw broccoli means it likely transits the colon more slowly than softened, cooked broccoli.

How Cooking Method Affects Gas Causing Compounds

Different cooking methods impact the gas causing compounds in broccoli differently:

  • Boiling: Boiling broccoli causes soluble fiber, sulfur compounds, FODMAPs and raffinose to leach into cooking water, reducing levels in the broccoli itself. One study found boiling removed the most gas-causing compounds.
  • Steaming: Steamed broccoli retains more sulfur compounds than boiled, but still loses some fiber, FODMAPs and raffinose.
  • Microwaving: Microwaved broccoli retains more sulfur compounds and fiber versus boiling and steaming.
  • Stir-frying: Stir-frying broccoli very briefly retains the most sulfur compounds and fiber compared to other cooking methods.

So boiling and steaming broccoli reduces gas-causing compounds the most, while stir-frying reduces them the least.

Tips to Reduce Gas from Broccoli

Here are some tips to help reduce gas and bloating from eating broccoli:

  • Cook broccoli by boiling, steaming or microwaving to reduce fiber, FODMAPs and raffinose.
  • Avoid eating large portions of raw broccoli if you are sensitive to gas.
  • Start with small servings of broccoli and gradually increase over time to allow gut bacteria to adjust.
  • Chew raw broccoli thoroughly to break down fiber and speed digestion.
  • Take an over-the-counter gas relief product like simethicone with broccoli.
  • Avoid broccoli if you have an underlying condition like IBS that makes you prone to gas.

The Bottom Line

Raw broccoli does tend to cause more gas and bloating issues than cooked broccoli for most people. The main reasons are broccoli’s insoluble fiber content and presence of sulfur compounds, raffinose, and fructans – all of which can lead to excess gas.

Cooking broccoli using methods like boiling, steaming, and microwaving can reduce these gas-causing nutrients and anti-nutrients by leaching them into cooking water. Starting with small amounts of cooked broccoli and gradually increasing intake allows the digestive system to better tolerate this healthy but gassy veggie.

While a little gas and bloating is normal, those with chronic gastrointestinal issues like irritable bowel syndrome may need to avoid broccoli altogether. But for most people, cooked broccoli can be enjoyed as part of a healthy, vegetable-rich diet.