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Onion Calories
Low calorie, source of vitamin C, contains antioxidants
CALORIES
GI
POTASSIUM
FIBER
Onion Nutrition Facts
Selected: 100 g
40
KCAL / 100G
Carbs
9.3g
· 88%
Protein
1.1g
· 10%
Fat
0.1g
· 2%
Fiber
1.7g
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
Onion Glycemic Index
GLYCEMIC INDEX
GLYCEMIC LOAD
Accounts for portion size — a more realistic measure than GI alone.
Is 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 Onion Contain Allergens?
No known major allergens
Which Diets Is 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
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.
Foods Similar to Onion
Onion — Frequently Asked Questions
How many calories are in onion?
Onion provides 40 calories per 100 grams. It is a relatively low-calorie vegetable.
How many carbs are in onion?
There are 9.3 grams of carbohydrates in 100 grams of onion. Carbohydrates make up most of its listed macronutrient content.
Is onion high in protein?
Onion is not a high-protein food. It contains 1.1 grams of protein per 100 grams.
Does onion contain fat?
Onion is very low in fat, with 0.1 grams per 100 grams. It can fit meals that aim to keep fat intake low.
What is the glycemic index of onion?
Onion has a glycemic index of 15. This places it in the low-GI range.
Is onion a good source of fiber?
Onion contains 1.7 grams of fiber per 100 grams. Fiber contributes to its carbohydrate content.
Is onion good for a calorie-controlled diet?
With 40 calories per 100 grams, onion can fit a calorie-controlled eating pattern. It is also very low in fat.
Can vegans and vegetarians eat onion?
Yes, onion is compatible with vegan and vegetarian diets. It also fits omnivore, paleo, Mediterranean, flexitarian, and gluten-free diets.
Is onion gluten-free?
Yes, onion is compatible with a gluten-free diet. It is listed as an unprocessed vegetable.
Is onion processed food?
No, onion is classified as unprocessed. It belongs to the vegetables category.
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Nutrition data compiled from USDA FoodData Central and scientific sources.