How Many Calories are in a Cup of Broccoli? The Real Answer for Your Meal Prep

You're standing in the kitchen, scale out or measuring cup in hand, wondering exactly how many calories are in a cup of broccoli before you toss it into the stir-fry. It seems like a simple question. It isn't. Not really. Most people just Google a number, see "31," and move on with their day, but if you’re actually tracking macros or trying to hit a specific caloric deficit, that "31" can be wildly misleading depending on how you prepped that green tree-looking vegetable.

Broccoli is a nutritional powerhouse. Everyone knows that. But the density of a cup changes the moment you apply heat or a knife. A cup of large, airy florets is mostly oxygen. A cup of finely chopped stalks? That’s a whole different caloric density.

The Raw Truth About Broccoli Calories

If you’re eating it raw—maybe dipped in some hummus or just crunching away like a rabbit—a standard one-cup serving of raw broccoli contains roughly 31 calories. According to the USDA FoodData Central database, that cup (about 91 grams) also brings about 6 grams of carbs, 2.5 grams of protein, and practically zero fat.

It’s basically high-volume water.

But honestly, who eats exactly one cup of perfectly sized florets? If you chop it into tiny bits, you can fit nearly double the amount of broccoli into that same measuring cup. Now you’re looking at 50 or 60 calories. It’s still low, sure, but if you’re doing this three times a day, the math starts to drift. This is why most nutritionists, including folks like Rhonda Patrick who talk extensively about sulforaphane, suggest weighing your greens in grams rather than relying on volume. Volume lies. The scale tells the truth.

Why the Cut Matters

Think about the structure. Broccoli has a "canopy." Those florets are bushy. When you measure "a cup," you’re measuring a lot of air trapped between the tiny green buds. If you use the stems—which you absolutely should because they are delicious and fiber-rich—the weight increases significantly.

• Large Florets: Might only weigh 75g per cup.
• Chopped Small: Usually hits that 91g to 100g mark.
• Shredded (Broccoli Slaw): Can easily reach 110g or more.

What Happens When You Cook It?

Cooking changes everything. When you steam or boil broccoli, the cell walls break down. The vegetable wilts. It collapses.

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If you take two cups of raw broccoli and steam them, they might shrink down to fit into a single cup. So, if you are tracking how many calories are in a cup of broccoli that has been cooked, the number jumps to about 55 calories per cup.

Why? Because it’s denser. You’re fitting more actual plant matter into the same space.

The Cooking Method Trap

Here is where people mess up their "healthy" diet. Broccoli is a literal sponge. Its structure is designed to soak up whatever liquid it touches.
If you sauté that cup of broccoli in just one tablespoon of olive oil, you’ve just added 120 calories. Your 31-calorie snack is now a 151-calorie side dish.
If you roast it? Roasting removes water. It concentrates the sugars. It makes it taste incredible—shout out to the Maillard reaction—but it also means you might eat three cups of "raw equivalent" broccoli in one sitting because it’s so small and delicious.

The Fiber and Net Carb Factor

We can't talk about calories without talking about fiber. Out of those 6 grams of carbs in a cup, about 2.4 grams are fiber.

For the keto crowd or those tracking net carbs, this is huge. You’re looking at roughly 3.5 to 4 grams of net carbs per cup. This fiber isn't just a "free" calorie; it's a metabolic tool. It slows down digestion. It feeds the Akkermansia bacteria in your gut. This is why a calorie of broccoli is fundamentally different from a calorie of soda. The broccoli requires energy to burn. It’s thermogenic.

Beyond the Calorie: Sulforaphane and E-E-A-T

When we look at the work of researchers like Dr. Jed Fahey from Johns Hopkins, we see that broccoli isn't just "low calorie." It's a chemical factory.
It contains glucoraphanin. When you bite it or chop it, an enzyme called myrosinase converts that into sulforaphane.

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Sulforaphane is perhaps one of the most potent natural triggers for our body's antioxidant defense system (the Nrf2 pathway).

• Pro tip: If you cook your broccoli, you kill the myrosinase enzyme.
• The fix: Let the chopped broccoli sit for 40 minutes before cooking, or add a pinch of mustard seed powder to the cooked greens to "reactivate" the health benefits.

Common Misconceptions About Broccoli Nutrition

I’ve heard people say that broccoli has "negative calories."
Let's be real. It doesn't.
While your body does spend energy chewing and digesting fiber, it doesn't spend more than the 31 calories the broccoli provides. It’s a myth. A persistent, annoying myth.

Another one: "The stems have no nutrients."
Actually, the stems are packed with fiber and have a very similar vitamin profile to the tops. They just need to be peeled because the outer skin is woody. If you throw them away, you're throwing away money and nutrition.

Is Frozen Broccoli Different?

Usually, no.
In fact, frozen broccoli is often blanched and frozen at peak ripeness. This locks in the nutrients. Sometimes, frozen broccoli can actually be more nutrient-dense than the "fresh" head that’s been sitting on a truck for nine days and then under grocery store lights for another three.
Calorie-wise? It’s the same. Just watch out for "frozen broccoli in sauce" packs. Those sauces are calorie bombs filled with cornstarch and low-quality oils.

Comparing Broccoli to Other Greens

If you're choosing your veggies based on "bang for your buck," here is how a cup of raw broccoli stacks up against its cousins:

1. Spinach: About 7 calories per cup (it’s mostly water).
2. Kale: About 33 calories per cup.
3. Cauliflower: About 25 calories per cup.
4. Brussels Sprouts: About 38 calories per cup.

Broccoli sits right in the middle. It’s heartier than spinach but less calorie-dense than a starch like peas or corn.

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How to Actually Track Broccoli Calories Accurately

If you are serious about your data, stop using cups. Buy a $10 digital kitchen scale.

1. Place a bowl on the scale and tare it to zero.
2. Add your broccoli (raw or cooked).
3. Multiply the weight in grams by 0.34 (for raw) or 0.55 (for cooked).
4. That is your actual calorie count.

It takes ten seconds. It removes all the guesswork about whether your "cup" was packed tight or loose.

Actionable Takeaways for Your Next Meal

Forget the "31 calories" rule of thumb for a second and focus on the quality of the intake. To get the most out of your broccoli without accidentally doubling your caloric intake:

• Steam, don't boil. Boiling leaches the Vitamin C and glucosinolates into the water. Unless you're drinking the broccoli water, you're losing the good stuff.
• Air fry for texture. If you hate mushy broccoli, toss it in an air fryer at 390°F for 6-8 minutes with a tiny spray of avocado oil. You get the crunch of roasting with a fraction of the oil calories.
• Season aggressively. Lemon juice, red pepper flakes, and garlic powder add zero calories but make the vegetable taste like a cheat meal.
• Watch the "Hidden" Calories. Adding a handful of cheddar cheese (115 calories) or a dollop of ranch (140 calories) turns a healthy side into the caloric equivalent of a small burger.

Broccoli is arguably the best "filler" food on the planet. You can eat a massive volume, feel physically full, and still be under your caloric goals. Just stay mindful of the scale and the sauté pan.

Start by weighing your portion for dinner tonight just once. You’ll be surprised at how much—or how little—a "cup" actually looks like on your plate. Once you see the volume on the scale, you can eye-ball it much more effectively in the future. Better data leads to better results, period.