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White onion Calories
Low-calorie vegetable rich in vitamin C and antioxidants
In season: Spring · Summer · Autumn · Winter
CALORIES
GI
POTASSIUM
FIBER
Quick answer
1 piece (medium) of White onion (80 g) has 32 calories. That works out to 40 calories per 100 g. It contains 7.4 g of carbs, 0.9 g of protein, 0.1 g of fat and 1.4 g of fiber. Its 5.9 mg of Vitamin C covers 7% of the Daily Value. Its glycemic index is 15 (low), so it raises blood sugar slowly.
What is White onion?
White onion is a crisp, juicy bulb with pale skin and a clean, savoury flavour. It is widely used in Mexican and other Latin American cooking, often finely chopped into salsa or served raw as a garnish; cooks around the world also add it to soups, stews and sautés. Its flavour softens and becomes sweeter as it cooks.
It is a low-calorie vegetable with some fibre and vitamin C. For a fresh, crunchy topping, pair it with tomatoes, herbs and lime or lemon; if you prefer a gentler raw flavour, slice it thinly and briefly rinse under cold water before serving.
White onion Nutrition Facts
Selected: 100 g
40
KCAL / 100G
Carbs
9.3g
· 3% DV
Protein
1.1g
· 2% DV
Fat
0.1g
· 0% DV
Fiber
1.7g
· 6% DV
DV is the share of the daily value covered, on a 2,000 kcal reference diet.
Calories come from: Carbs 88% · Protein 10% · Fat 2%
White onion Vitamins & Minerals
Vitamins
Vitamin C
7.4mg · 8% DV
B6
0.12mg · 7% DV
Folate
19µg · 5% DV
B1
0.04mg · 3% DV
Minerals
Phosphorus
29mg · 4% DV
Potassium ⭐
146mg · 4% DV
Calcium
23mg · 2% DV
Magnesium
10mg · 2% DV
How Nutritious Is White onion?
Nutrient density
High
How many vitamins, minerals and how much fiber this food carries per calorie. A high score means a lot of nutrition for few calories.
Satiety score
Medium
An EatBetter score computed from fiber, protein and calorie density. A high score means staying full longer on the same calories.
Both scores are calculated per 100 g and do not change with the selected portion. The satiety score is EatBetter's own calculation, not a clinical measure.
White onion Glycemic Index
GLYCEMIC INDEX
GLYCEMIC LOAD
Accounts for portion size — a more realistic measure than GI alone.
How to Burn Off White onion
To burn the 40 calories in 100 g:
🚶
Walking (5 km/h)
🏃
Running (8 km/h)
🚴
Cycling
🏊
Swimming
Times are calculated with the MET equation for a 70 kg adult. Actual burn varies with your weight, age and pace.
Is White onion Processed?
NOVA 1
Unprocessed
1. Unprocessed
2. Minimally Processed
3. Processed
4. Ultra-Processed
NOVA classifies foods into 4 groups by industrial processing. NOVA 1 (unprocessed) is the healthiest.
Does White onion Contain Allergens?
No known major allergens
Which Diets Is White onion Good For?
Vegan
✓ Suitable
Vegetarian
✓ Suitable
Gluten-Free
✓ Suitable
Dairy-Free
— Not suitable
Mediterranean
✓ Suitable
Paleo
✓ Suitable
Whole30
— Not suitable
DASH
— Not suitable
Keto
— Not suitable
Low FODMAP
— Not suitable
White onion Fat Profile
SATURATED
0.03g
MONOUNSATURATED
0.01g
POLYUNSATURATED
0.02g
Omega 6:3 ratio 2:1
Below the ideal 4:1 — a good omega balance.
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Frequently Asked Questions About White onion
What is the difference between a white onion and a yellow onion?
White onions are usually milder, juicier, and thinner-skinned than yellow onions. They work especially well raw or in quick-cooking dishes, while yellow onions develop a deeper, sweeter flavor during longer cooking.
Can you eat a white onion raw?
Yes, white onions can be eaten raw. Their crisp texture works well in salads, sandwiches, and salsa; if the flavor is too sharp, soak sliced onion briefly in cold water and drain it before serving.
What is the difference between a white onion and a red onion?
White onions tend to taste sharper and less sweet, while red onions are often milder and add color to dishes. White onions suit cooked recipes and salsa; red onions are a popular choice for salads and pickling.
How should you store a white onion?
Keep a whole white onion in a cool, dry, well-ventilated place, away from sealed plastic bags. Refrigerate cut onion in an airtight container and use it within a few days.
How do you mellow the taste of a white onion?
To mellow a white onion, slice it and soak it briefly in cold water, then drain and pat it dry. For salads, tossing it with lemon juice or vinegar also softens its sharp bite.
Why does cutting a white onion make your eyes water?
Cutting a white onion releases sulfur-containing compounds that irritate the eyes and trigger tears. A sharp knife, chilling the onion before cutting, and working near good ventilation can reduce the irritation.
Can you freeze a white onion?
Yes, you can freeze a white onion, though it will become soft after thawing. Peel and chop it first, then freeze it in an airtight bag or container for use in cooked dishes.
How can you tell if a white onion is fresh?
Choose a white onion that feels firm and heavy, with dry, intact skin. Soft spots, dampness, mold, or a sour smell suggest spoilage; a dry outer skin is normal and does not mean the onion is bad.
Can you use a white onion instead of a yellow onion?
Yes, white onion can replace yellow onion in most recipes, especially when the onion is cooked briefly or served raw. The finished dish may taste a little sharper and less sweet than it would with yellow onion.
Can you eat a sprouted white onion?
Yes, a firm white onion with a small green sprout is generally still usable; remove the sprout if you prefer. Discard the onion if it is moldy, slimy, very soft, or smells rotten.
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Nutrition data compiled from USDA FoodData Central and scientific sources.