Onion (raw)
A flavor base for almost every savory meal-prep dish.
1 Amount
How it fits your macros
Get your daily targets with the macro calculator to see what share of your day this portion covers.
Onion for gym-goers
Per 100 g, onion (raw) provides 40 kcal, 1.1 g protein, 9.3 g carbohydrate (1.7 g fiber, 4.2 g sugars) and 0.1 g fat (0 g saturated). It's mainly a carb source, so pair it with some protein to make a complete meal.
A typical serving (1 medium onion, about 110 g) comes to roughly 44 kcal and 1.2 g protein.
These are typical averages. Brand, variety, ripeness and cooking method all shift the numbers, so weigh food in the same state (raw or cooked) as the entry you log.
About Onion
Raw yellow or brown onion is the flavor base of most savory cooking. At around 40 kcal per 100 g it has a bit more carbohydrate and natural sugar than leafy greens, which is why it isn't considered keto-friendly in larger amounts. Onions also contain sulfur compounds and the flavonoid quercetin, behind both their sharp taste and much of the research interest in them.
In a gym diet
Onions are rarely a big part of a meal, but they make lean protein, rice dishes and sauces taste far better, and that helps you stick to any diet. On a cut they add flavor for very little energy, especially compared with creamy sauces or extra oil. They're cheap and keep for weeks, so they're a natural fit for budget meal prep on a bulk. The protein they add is minimal.
Preparation and cooking
Slow-caramelized onions turn sweet, but most of the added calories come from the oil or butter. Cooking drives off water, so weigh onions raw for this entry. To soften raw onion's bite in salads, soak the slices in cold water for ten minutes.
Buying and storage
Choose firm, heavy onions with dry, papery skins and no soft spots or sprouting. Keep whole onions somewhere cool, dark and ventilated, away from potatoes. Once cut, wrap them and refrigerate for a few days.
Things to watch
Onions are high in fructans, a FODMAP that commonly triggers bloating in people with irritable bowel symptoms. Low-FODMAP plans often use garlic-infused oil or green onion tops instead. Battered onion rings and fried onions are far more calorie-dense than the onion itself.
Meal ideas
- Turkey chili with diced onion, peppers, kidney beans, tomatoes and smoked paprika.
- Quick pickled red onions to top chicken wraps, rice bowls and salads.
- Steak and onion stir-fry with peppers, served over rice with a soy-garlic glaze.
Nutrient highlights
None of the tracked vitamins and minerals reaches 10% of the Daily Value per 100 g, so you're eating it mainly for its macros.
How it ranks among 19 Vegetables
| Protein per 100 kcal | 2.8 g | #18 of 19 |
| Protein per 100 g | 1.1 g | #15 of 19 |
| Fiber per 100 g | 1.7 g | #15 of 19 |
| Lowest calories per 100 g | 40 kcal | #13 of 19 |
Ranked within this category of the gym.diet food database (1 = best for that measure).
Similar foods
Bell pepper, red (raw)
31 kcal · P 1 · C 6 · F 0.3
→Carrot (raw)
41 kcal · P 0.9 · C 9.6 · F 0.2
→Beetroot (raw)
43 kcal · P 1.6 · C 9.6 · F 0.2
→Sweet corn, yellow kernels (raw)
86 kcal · P 3.3 · C 19 · F 1.4
→Cucumber, with peel (raw)
15 kcal · P 0.7 · C 3.6 · F 0.1
→Tomato, red (raw)
18 kcal · P 0.9 · C 3.9 · F 0.2
Source
Approximate per-100 g values compiled from USDA FoodData Central (SR Legacy / Foundation Foods), rounded. Daily Values are the U.S. FDA reference amounts for adults (2,000 kcal diet).
Frequently asked questions
How many calories are in onion?
Onion (raw) has about 40 kcal per 100 g, or roughly 44 kcal per 1 medium onion (110 g).
How much protein is in onion?
About 1.1 g of protein per 100 g and 1.2 g per 1 medium onion. That works out to 2.8 g per 100 kcal, so it's not primarily a protein source.
Is onion good for cutting or bulking?
It works in either phase. What matters is how it fits into your total calories and protein for the day.
Do onions have carbs?
Yes, more than many vegetables, mostly natural sugars and fiber. A typical cooking portion holds a modest amount, but strict keto dieters may need to measure.
Are raw onions healthier than cooked?
Raw onions keep more of their sulfur compounds and vitamin C; cooked ones are sweeter and easier to digest. Both are worth eating, so go by your tolerance and the dish.
Nutrition Facts
* The % Daily Value tells you how much a nutrient in a serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice. Values approximate.