Protein content
A 1 cup chopped serving of onion contains 1.8 g of protein - only a minor source of protein, about 4% of the 50 g Daily Value.
Share of this food's calories that come from protein - it is more of an energy food than a protein food.
| Serving | 1 cup chopped (160 g) |
|---|---|
| Protein per serving | 1.8 g |
| Protein per 100 g | 1.1 g |
| Calories per serving | 64 kcal |
| Protein density | 11% of calories |
| Share of 50 g Daily Value | 4% |
| Protein quality | Incomplete protein |
| Category | Vegetables |
| Food type | Whole food |
| USDA record | FoodData Central #170000 |
A typical 1 cup chopped serving of onion contains 1.8 grams of protein (1.1 g per 100 g), which makes it only a minor source of protein. That covers roughly 4% of the 50 g reference Daily Value, so it adds toward your protein total for the day.
Only about 11% of the calories in onion come from protein, so it is more of an energy food than a protein food. It is worth eating for other reasons; the protein it adds to a day is incidental.
Among the 105 vegetables in the database, onion ranks 57th by protein per serving, and 666th out of all 796 foods on the site. Set against alfalfa sprouts, another vegetable entry in the database, a serving carries about 0.5 g more protein (alfalfa sprouts has 1.3 g per 1 cup).
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 above is measured by volume at 160 g. The per-100 g figure lets you compare it directly against any other food here, whatever its serving.
Source: USDA FoodData Central #170000 - "Onions, raw" (SR Legacy, published 4/1/2019). Values are the published reference figures for that record, not lab measurements for a specific brand or batch.
Quick answers
Onion has 1.1 g of protein per 100 g. A typical 1 cup chopped serving (160 g) provides 1.8 g.
No. Onion is an incomplete protein on its own; pairing it with other protein sources across the day covers the full range of essential amino acids.
A 1 cup chopped serving of onion contains 1.8 g of protein, about 4% of the 50 g reference Daily Value.
Onion is only a minor source of protein, and about 11% of its calories come from protein, which makes it more of an energy food than a protein food. Set against alfalfa sprouts, another vegetable entry in the database, a serving carries about 0.5 g more protein (alfalfa sprouts has 1.3 g per 1 cup).
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