Broccoli is one of the lowest-carb vegetables you can eat. A full cup of raw chopped broccoli contains just 6 grams of total carbohydrates and about 2.4 grams of fiber, putting its net carb count at roughly 3.6 grams. That makes it a staple for keto, low-carb, and blood sugar-conscious eating plans alike.
Carb Breakdown per Serving
One cup of raw chopped broccoli (about 91 grams) delivers 6 grams of total carbs, 2.4 grams of fiber, and 2.6 grams of protein, with virtually no fat. Fiber doesn’t raise blood sugar, so when you subtract it, you’re left with only 3.6 grams of net carbs per cup. That’s remarkably low for a vegetable that fills a decent portion of your plate.
For context, broccoli has a glycemic index of just 10, which is about as low as a food can score. Most foods under 55 are considered low-glycemic; broccoli barely registers. This means it causes almost no spike in blood sugar, even in larger servings.
How Broccoli Fits a Keto Diet
Ketogenic diets typically cap net carbs at around 50 grams per day. At 3.6 net carbs per cup, you could eat several generous servings of broccoli and still have plenty of carb budget left for other foods. Roughly 1,000 grams of broccoli (about 11 cups) would be needed to hit 50 grams of net carbs, so running into trouble with broccoli alone is nearly impossible.
This is one reason broccoli appears on virtually every “keto-friendly vegetable” list. It’s filling enough to serve as a main side dish, pairs well with high-fat foods like cheese and butter, and won’t push you out of ketosis even in generous portions.
Raw vs. Cooked: Does It Change?
Cooking broccoli doesn’t significantly change its carb content per gram, but it does change how much fits in a cup. Raw broccoli is bulkier, so a cup of raw florets weighs less (around 91 grams) than a cup of cooked, softened broccoli. When broccoli is steamed or boiled, it shrinks and compresses, meaning a measured cup of cooked broccoli contains more actual broccoli by weight and therefore slightly more carbs per cup.
The difference is small enough that it won’t matter for most people tracking carbs casually. If you’re counting precisely, weigh your broccoli in grams rather than measuring by cup volume, and you’ll get a consistent number regardless of how it’s prepared.
How Broccoli Compares to Other Low-Carb Vegetables
Broccoli sits right alongside cauliflower, its closest relative. One cup of raw cauliflower (107 grams) has 5.5 grams of total carbs and 2 grams of fiber, giving it about 3.5 net carbs. The difference between the two is negligible. Leafy greens like spinach and lettuce are even lower in carbs per cup, but they’re also much lighter and less filling.
- Broccoli (1 cup raw): 6g total carbs, 2.4g fiber, ~3.6g net carbs
- Cauliflower (1 cup raw): 5.5g total carbs, 2g fiber, ~3.5g net carbs
- Spinach (1 cup raw): ~1.1g total carbs, 0.7g fiber, ~0.4g net carbs
Starchier vegetables tell a different story. A cup of cooked corn has around 31 grams of net carbs, and a medium potato comes in above 30 grams. Broccoli delivers roughly one-tenth the carb load of these options while providing far more bulk on the plate.
Nutrient Density Beyond Carbs
Part of what makes broccoli especially valuable on a low-carb diet is how much nutrition it packs into those few carbs. A cup of cooked broccoli provides about 117 milligrams of vitamin C (well over 100% of most adults’ daily needs) and roughly 254 micrograms of vitamin K, which is more than double the recommended daily intake. It also delivers over 500 milligrams of potassium, a mineral many people on restrictive diets fall short on.
Broccoli also contains a compound called glucoraphanin, which converts into sulforaphane when you chew or chop it. Sulforaphane has been widely studied for its antioxidant and anti-inflammatory properties. The concentration varies quite a bit from head to head. Testing of 31 broccoli heads from different supermarkets found glucoraphanin levels ranging from nearly undetectable to 1.13 micromoles per gram, with an average around 0.38. Fresher broccoli and certain hybrid varieties tend to have higher concentrations, so buying fresh and not overcooking it gives you the best chance of getting meaningful amounts.
Best Ways to Eat Broccoli on a Low-Carb Diet
Steaming broccoli for three to four minutes preserves most of its nutrients while softening the texture. Roasting at high heat with olive oil caramelizes the edges and concentrates the flavor without adding carbs. Both methods keep the net carb count well under 5 grams per cup.
Common low-carb pairings include broccoli tossed in butter and garlic, broccoli and cheddar soup thickened with cream cheese instead of flour, and raw broccoli florets dipped in ranch or blue cheese dressing. Riced broccoli (pulsed in a food processor) also works as a lower-carb substitute in fried rice dishes, though cauliflower rice is more common simply because its milder flavor blends more easily.