Every 100 kcal of natto brings 9.2 g of protein. On that measure it ranks 17th of the 31 soy foods in this database and 269th of all 796 foods on the site. Measured by weight instead, its 19.4 g per 100 g ranks 10th in its group.
Protein accounts for roughly 37% of the calories in natto, making it very protein-dense. The rest comes from fat and carbohydrate, so it adds a solid amount of protein while still carrying real energy - useful when you are eating to a calorie target rather than under one.
Weight for weight, natto has 1.8 g of protein for each gram of fat (19.4 g against 11 g per 100 g).
Set against veggie burger, another soy food entry in the database, a serving carries about 1.4 g more protein (veggie burger has 15.7 g per 1 patty).
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 volume at 88 g, and it covers about 34% of the 50 g FDA Daily Value for protein.
One of the few plant foods that is a complete protein, with all nine essential amino acids.
Serving sizes
Protein in common portions of natto
Protein and calories in Natto for 100 g, the site serving and USDA household portions.
Portion
Weight
Protein
Calories
100 g
100 g
19.4 g
211 kcal
1/2 cup (serving used here)
88 g
17.1 g
186 kcal
1 cup
175 g
33.9 g
369 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 natto
The nine essential amino acids in Natto, per 100 g, per serving and per gram of protein.
Amino acid
Per 100 g
Per serving
mg per g protein
leucine
1.51 g
1.33 g
78
lysine
1.14 g
1 g
59
valine
1.02 g
0.9 g
53
isoleucine
0.931 g
0.82 g
48
threonine
0.813 g
0.72 g
42
phenylalanine
0.941 g
0.83 g
49
methionine
0.208 g
0.18 g
11
histidine
0.512 g
0.45 g
26
tryptophan
0.223 g
0.2 g
11
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.
19.4 g. The 1/2 cup serving used on this page weighs 88 g and so carries 17.1 g.
How much protein do you get per 100 calories of natto?
9.2 g. That figure divides its 19.4 g of protein per 100 g by its 211 kcal per 100 g, so it does not depend on serving size.
Is the protein in natto complete?
Yes. The protein in natto 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 natto?
About 34%. One 1/2 cup serving has 17.1 g, and the FDA Daily Value for protein is 50 g.
Figures from USDA FoodData Central record #172443 (Natto), 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.