Does Broccoli Cause Gas? (Data-Backed Answer)


For most people, broccoli doesn’t cause a noticeable amount of gas.

However, for those who really love broccoli and eat large amounts of it at a time (we’re talking about a full head or more), there is a possibility that broccoli can contribute to bloating and gas problems.

I’ll quickly break down the reasons that broccoli causes flatulence in large amounts, and by the end you should have a pretty clear idea if broccoli is giving you stomach issues, or if it’s something else.

The Main Reasons That Broccoli Can Cause Bloating and Gas

The vast majority of gas is produced by bacteria in your gut fermenting hard-to-digest carbohydrates.

That’s it.

Broccoli contains a few carbohydrates that can’t be digested by your small intestine, so they end up fermenting in your gut:

  • Fiber – Most vegetables are high in fiber. Fiber is good for many aspects of health, but too much can produce excess gas.
  • Tough to digest sugars – Certain sugars like glucose are easy to digest, but broccoli also contains fructose and oligosaccharides, which essentially don’t digest at all in the small intestine.

It’s important to note that these are not “bad” carbohydrates by any means. In fact, they essentially act as food to the bacteria in your gut and help keep you healthy. It’s just that too much of them can cause you stomach issues.

Fiber Content of Broccoli

You’re probably familiar with fiber already, so we can quickly go through this.

Below is the macronutrient profile for 100 grams of broccoli, which includes fiber.

Energy (kcal) 34
Protein (g) 2.82
Total Lipid (g) 0.37
Carbohydrate (g) 6.64
Fiber (g) 2.6
Sugars (g) 1.7

Like most vegetables, broccoli is very low in calories, and most of its carbohydrates come from fiber.

However, note that while 2.6 grams of fiber is more than most foods, it’s still less than other foods like beans. For example, cooked chickpeas have 7.6 grams of fiber per 100 grams.

While eating a lot of broccoli won’t be an issue because of calories, the fiber can add up.

Oligosaccharides in Broccoli

Oligosaccharides are a class of carbohydrates that we lack the enzyme to digest, so they end up having to be broken down by our gut bacteria.

Broccoli has a significant amount of oligosaccharides, although much less compared to foods like beans.

The data below shows a breakdown of the sugars in 100 grams of broccoli:

Moisture 86 g
Fructose 0.88 g
Sucrose 0.65 g
Sorbitol 0.2 g
Total FOS 0.78 g
Stachyose 0.11 g

Let me walk you through the most important parts of this:

  • Total FOS (Fructooligosaccharides) – One of the 2 main types of oligosaccharides, and the one that broccoli has the most of.
  • Stachyose – Another oligosaccharide that is part of the raffinose family oligosaccharides (RFO). Despite many claims I’ve seen, broccoli doesn’t actually have raffinose, only stachyose. It doesn’t make any practical difference though.
  • Fructose – Fructose is not an oligosaccharide, but it is very hard to digest and studies have shown that fructose can contribute to flatulence. Broccoli has a good amount of fructose, and note that sucrose is literally half fructose as well.

I also included the sugar alcohol sorbitol on the table above for completeness. While sorbitol can cause cramping and stomach problems, it’s not usually an issue until you consume at least 5 grams, which is an absolute ton of broccoli.

Can You Prevent Gas From Eating Broccoli?

As mentioned, most of these carbohydrates are quite healthy, so while I understand that gas isn’t comfortable, it’s likely not harming you.

The only things you can really do to limit gas after eating vegetables like broccoli are:

  • Eat smaller portions
  • Take an enzyme supplement like Beano, which will break down many oligosaccharides before your gut

Cooking does generally improve digestion of vegetables, but it likely won’t help too much here.

There’s some evidence that cooking legumes reduces oligosaccharide content, but you’re probably not cooking broccoli in large amounts of water, so it’s unlikely that cooking will reduce oligosaccharide content in broccoli.

About the author

Dale Cudmore

Your friendly neighborhood vegan from Toronto. Chemical engineer turned semi-professional soccer player and freelance nutrition writer. I've been vegan for years and try to make life easier for others by sharing what I've learned.