According to the data of USDA FoodData Central, in 100 g of raw broccoli there are 2,82 g of protein, which makes it among the vegetables with the highest protein density for calories. With only 34 calories for that same amount, around 29 % of the whole energy comes from proteins, which beats carrots (17 %) and green beans (22 %).

One cup of chopped raw broccoli weighs 91 g and gives 2,6 g of protein together with 31 calories.

Broccoli: Protein and Nutrition Facts

When one cooks it, the values change according to the method used. Boiling brings the protein level down to 2,38 g for 100 g, because water-soluble amino acids spill into the water, a fall of around 15,6 % compared with the raw. Steaming keeps it a bit higher, at 2,50 g for 100 g (still 11,3 % less then raw).

With roasting, the protein goes up to 3,10 g for 100 g, because the water dries out and removes 15, 20 % of the weight, while the protein almost fully stays.

A cup of boiled and drained broccoli weighs 156 g and holds 3,7 g of protein and 55 calories. A cup steamed gives around 3,9 g of protein and 54 calories. The cooked cup weighs much more than the raw (156 g against 91 g), because broccoli shrinks and packs during cooking, so two cups raw match to one cooked by volume.

A bag of 10 units (284 g) of frozen broccoli flowers holds about 8,2 g of protein. Frozen broccoli has even a bit more protein than fresh raw, at 2,90 g for 100 g, probably because of blanching and packing at best ripeness. After cooking from frozen, even so, it drops again to about 2,60 g for 100 g.

A broccoli head in stores weighs between 350 g and 550 g, so a whole middle head provides around 10… 15,5 g of protein.

Broccoli sits in the middle group, but it really stands out by the ratio of protein to calories.

For 100 g raw broccoli, the amino acid mix includes around 0,13 g of leucine, 0,09 g of isoleucine, 0,12 g of valine, 0,05 g of tryptophan and 0,10 g of lysine. It is not complete protein alone, but the content of branched chain amino acids is notable for a vegetable. Just leucine forms around 4,6 % of the whole protein.

If one uses only the flowers from whole broccoli, one dumps 30, 45 % of the weight. Few know that the stem itself carries around 2,98 g of protein for 100 g, a bit more than the flowers. Removing the tough outside of the stem cuts the waste to around 15 %, and the soft inner part is fully edible with protein density that matches or even beats that of the flowers.

The fiber content in raw broccoli is 2,6 g for 100 g, so one cup of raw chopped gives around 2,4 g of fiber. Almost ideal 1:1 ratio. Vitamin C reaches an impressive 89,2 mg for 100 g raw (around 99 % of the daily need), although boiling drops it to 64,9 mg, a loss of 27,2 %.

Potassium is 316 mg for 100 g raw, with 47 mg of calcium and 0,73 mg ofiron.