A 3-ounce serving of crab meat contains roughly 16 to 19 grams of protein, depending on the species and preparation. That’s comparable to a similar portion of chicken breast, but with a fraction of the fat and only about 82 calories. This makes crab one of the leanest protein sources available.
Protein by Serving Size
Per 100 grams (about 3.5 ounces), crab meat delivers 19.4 grams of protein alongside just 1.5 grams of fat. A standard 3-ounce portion lands around 16 to 17 grams. If you’re eating a full cup of steamed, flaked crab meat (about 118 grams), you’ll get roughly 21 grams of protein, which covers over 40% of the daily value.
Crab is also nearly carbohydrate-free, so almost all of its calories come from protein. At around 82 calories per 3-ounce serving, the protein-to-calorie ratio is exceptionally high. You’d need to eat roughly twice as much salmon to get the same amount of protein for the same calorie cost.
How Crab Compares Across Species
Blue crab, king crab, and snow crab are the most commonly sold varieties, and their protein content is similar enough that you don’t need to choose one over another for nutritional reasons. King crab legs tend to have slightly more meat per piece, so you may end up eating more protein in a single sitting simply because there’s more to work with. Snow crab and blue crab are leaner overall, with marginally less fat per serving.
Dungeness crab falls in the same range, typically offering 18 to 20 grams of protein per 100 grams. The differences between species are small enough that any crab you find at a market or restaurant will be a strong protein source.
Beyond Protein: What Else Crab Provides
Crab isn’t just a protein vehicle. A serving contains about 9 micrograms of vitamin B12, which is several times the daily recommendation and supports nerve function and red blood cell production. It also provides 37 micrograms of selenium (over half the daily value), a mineral that plays a role in thyroid health and immune defense, plus 3.6 milligrams of zinc.
Crab meat contains all nine essential amino acids your body can’t produce on its own, making it a complete protein. Histidine is the most abundant essential amino acid in the meat, while glutamic acid leads among the non-essential amino acids. This profile means crab delivers the full range of building blocks your muscles need for repair and growth.
Steamed, Canned, and Imitation Crab
How crab is prepared changes the nutritional picture. Steamed hard-shell crab retains its full protein content but comes with notable sodium: a cup of steamed, flaked crab meat contains about 764 milligrams, roughly a third of the recommended daily limit. If you’re watching sodium, rinsing canned crab before eating can help reduce that number.
Canned crab is convenient but often has added salt for preservation. The protein content stays comparable to fresh crab, though it can vary by brand. Check labels for added sodium and preservatives.
Imitation crab is a different product entirely. It contains no actual crab. It’s made from surimi, a paste of minced fish blended with starch, flavorings, and coloring. Because of those starch fillers, imitation crab contains carbohydrates that real crab does not, and it’s generally lower in protein and potassium. If you’re eating crab specifically for its protein content, the real thing is worth the price difference.
Mercury Levels in Crab
Crab is one of the lower-mercury seafood options. FDA testing across blue, king, and snow crab found an average mercury concentration of 0.065 parts per million, with a maximum of 0.61 ppm across 93 samples. For context, high-mercury fish like swordfish and king mackerel average above 0.7 ppm. This means crab is safe to eat multiple times per week for most adults, including pregnant women, under current FDA guidelines.
How Crab Fits a High-Protein Diet
If you’re aiming for 100 to 150 grams of protein per day, a single cup of crab meat covers about 15 to 20% of that goal for under 100 calories. Pairing crab with rice, vegetables, or a salad makes a complete meal without much calorie overhead. Crab cakes, crab salads, and crab-stuffed avocados are all practical ways to work it into regular meals.
One practical consideration: crab is more expensive per gram of protein than chicken, eggs, or canned tuna. It works well as a rotation protein, something you eat once or twice a week for variety and micronutrient diversity rather than as your daily staple. The combination of high protein, low fat, minimal mercury, and rich B12 and selenium content makes it one of the more nutritionally complete seafood options available.