Protein content
0.6 g of protein in 1 cup shredded (47 g) of romaine lettuce, or 7.2 g for every 100 kcal it supplies.
Share of this food's calories that come from protein - it is moderately protein-dense.
| Protein per 100 kcal | 7.2 g |
|---|---|
| Protein per 100 g | 1.23 g |
| Protein per serving | 0.6 g in 1 cup shredded (47 g) |
| Calories from protein | 29% |
| Leucine per serving | 0.04 g |
| Rank in vegetables, per 100 kcal | 31st of 105 |
| Rank of all foods, per 100 g | 712th of 796 |
| Share of 50 g Daily Value | 1% per serving |
| Protein quality | Incomplete protein |
One 1 cup shredded, 0.6 g protein.
Every 100 kcal of romaine lettuce brings 7.2 g of protein. On that measure it ranks 31st of the 105 vegetables in this database and 328th of all 796 foods on the site. Measured by weight instead, its 1.23 g per 100 g ranks 72nd in its group.
Around 29% of the calories in romaine lettuce come from protein, so it is moderately protein-dense. It contributes to a day's protein total, but the bulk of what it delivers is energy rather than amino acids - treat it as a contributor alongside a denser source, not as the protein in a meal.
USDA lists 0.3 g of fat per 100 g of romaine lettuce, too little for a protein-to-fat ratio to mean much.
Set against jalapeno peppers, another vegetable entry in the database, a serving carries about 0.5 g more protein (jalapeno peppers has 0.1 g per 1 pepper).
It is an incomplete protein on its own; pairing it with other plant foods across the day covers the full range of essential amino acids. The serving quoted here is measured by volume at 47 g, and it covers about 1% of the 50 g FDA Daily Value for protein.
Serving sizes
| Portion | Weight | Protein | Calories |
|---|---|---|---|
| 100 g | 100 g | 1.23 g | 17 kcal |
| 1 cup shredded (serving used here) | 47 g | 0.6 g | 8 kcal |
| 1 leaf inner | 6 g | 0.1 g | 1 kcal |
| 1 leaf outer | 28 g | 0.3 g | 5 kcal |
| 1 head | 626 g | 7.7 g | 106 kcal |
| 1 NLEA serving | 85 g | 1 g | 14 kcal |
Portion weights are the household measures listed on the USDA record; protein and calories scale from the per-100 g figures.
Amino acids
| Amino acid | Per 100 g | Per serving | mg per g protein |
|---|---|---|---|
| leucine | 0.076 g | 0.04 g | 62 |
| lysine | 0.064 g | 0.03 g | 52 |
| valine | 0.055 g | 0.03 g | 45 |
| isoleucine | 0.045 g | 0.02 g | 37 |
| threonine | 0.043 g | 0.02 g | 35 |
| phenylalanine | 0.065 g | 0.03 g | 53 |
| methionine | 0.015 g | 0.01 g | 12 |
| histidine | 0.021 g | 0.01 g | 17 |
| tryptophan | 0.01 g | 0 g | 8 |
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.
Related
Highest-protein vegetables per serving · Most protein-dense foods · Highest protein per 100 g
Quick answers
1.23 g. The 1 cup shredded serving used on this page weighs 47 g and so carries 0.6 g.
7.2 g. That figure divides its 1.23 g of protein per 100 g by its 17 kcal per 100 g, so it does not depend on serving size.
No. On its own, the protein in romaine lettuce is short of at least one essential amino acid; other protein sources across the day fill the gap.
About 1%. One 1 cup shredded serving has 0.6 g, and the FDA Daily Value for protein is 50 g.
Figures from USDA FoodData Central record #169247 (Lettuce, cos or romaine, raw), 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.