Every 100 kcal of flank steak brings 15 g of protein. On that measure it ranks 47th of the 133 meats in this database and 139th of all 796 foods on the site. Measured by weight instead, its 27.9 g per 100 g ranks 50th in its group.
About 60% of the calories in flank steak come from protein, which makes it extremely protein-dense - close to the practical ceiling for a whole food. Foods in this band are the ones that let you raise your protein intake without raising your calorie intake much at all.
Weight for weight, flank steak has 3.8 g of protein for each gram of fat (27.9 g against 7.4 g per 100 g).
Set against beef heart, another meat entry in the database, a serving carries about 0.5 g less protein (beef heart has 24.2 g per 3 oz cooked).
It is a complete protein - it supplies all nine essential amino acids in adequate amounts, so it can carry a meal's protein on its own. The serving quoted here is measured by weight at 85 g, and it covers about 47% of the 50 g FDA Daily Value for protein.
A lean cut with pronounced grain; slicing across the grain matters more here than with tender cuts.
Serving sizes
Protein in common portions of flank steak
Protein and calories in Flank steak for 100 g, the site serving and USDA household portions.
Portion
Weight
Protein
Calories
100 g
100 g
27.9 g
186 kcal
3 oz cooked (serving used here)
85 g
23.7 g
158 kcal
1 steak
383 g
106.9 g
712 kcal
Portion weights are the household measures listed on the USDA record; protein and calories scale from the per-100 g figures.
Amino acids
Essential amino acids in flank steak
The nine essential amino acids in Flank steak, per 100 g, per serving and per gram of protein.
Amino acid
Per 100 g
Per serving
mg per g protein
leucine
2.22 g
1.89 g
80
lysine
2.36 g
2.01 g
85
valine
1.38 g
1.17 g
49
isoleucine
1.27 g
1.08 g
46
threonine
1.11 g
0.94 g
40
phenylalanine
1.1 g
0.94 g
39
methionine
0.726 g
0.62 g
26
histidine
0.89 g
0.76 g
32
tryptophan
0.183 g
0.16 g
7
Per-100 g values are the amino acid analysis on the USDA record. The serving and per-gram-of-protein columns are arithmetic on those values; they are not a protein quality score.
SampleWhat goal trends look like after a week
109 g
Average per logged day
4 of 7
Days goal met
71%
Complete-protein share
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Sample figures for one made-up week against a 110 g goal, not your data. Red bars met the goal. Your own log fills this in with Premium.
27.9 g. The 3 oz cooked serving used on this page weighs 85 g and so carries 23.7 g.
How much protein do you get per 100 calories of flank steak?
15 g. That figure divides its 27.9 g of protein per 100 g by its 186 kcal per 100 g, so it does not depend on serving size.
Is the protein in flank steak complete?
Yes. The protein in flank steak supplies all nine essential amino acids in adequate amounts, so it can carry a meal's protein on its own.
What share of the protein Daily Value is one serving of flank steak?
About 47%. One 3 oz cooked serving has 23.7 g, and the FDA Daily Value for protein is 50 g.
Figures from USDA FoodData Central record #174774 (Beef, flank, steak, separable lean only, trimmed to 0" fat, all grades, cooked, broiled), SR Legacy data. USDA data is in the public domain. Values are the published reference figures for that record, not lab measurements for a specific brand or batch.