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  4. Onion

Onion has 40 kcal per 100 g. The aromatic foundation of Bulgarian cooking — every яхния and супа starts with лук. Caramelizing concentrates sugars and deepens flavor.

About this food

How should I track Onion?

For consistent tracking of Onion, weigh it raw. Cooking method changes both weight and calorie density — steaming barely changes anything, but roasting with oil or frying can double the calories. A systematic review (Whitton et al., Adv Nutr 2022) found vegetables are omitted from food logs 2–85% of the time, often because people assume they are "free" calorically. While most vegetables are indeed low-calorie, the fats added during cooking are not. Log the oil, butter, or dressing separately to keep your tracking accurate.

Macro Breakdown

Macro Split: 10% Protein, 88% Carbs, 2% Fat
Foods That Pair Well

Fruits

Orange

47 kcal0.9g protein

Beverages

Boza (Fermented Drink)

48 kcal0.5g protein

Traditional Bulgarian

Kiselo Zele (Sauerkraut)

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Carbs88%
Protein10%1.1g
Carbs88%9.3g
Fat2%0.1g

Nutrition Facts

Per 100g. Percentages reflect Daily Value (DV).

Energy
  • Calories
    40kcal—
Macronutrients
  • Protein
    1.1g2%
  • Carbohydrates
    9.3g—
  • Fat
    0.1g—
  • Fiberathlete
    1.7g6%
  • Sugar
    4.2g—
  • Saturated Fat
    0.0g—
Minerals
  • Sodium
    4mg—
  • Calciumathlete
    23mg2%
  • Ironathlete
    0mg1%
Vitamins
  • Vitamin Dathlete
    0.0mcg0%

% Daily Value based on FDA 2,000 kcal reference diet. Strength trainees have different needs — see highlighted nutrients.

Serving Calculator

Serving Calculator

Onion — values for 80g

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Primary macros

Calories
32
kcal
Protein
0.9
g
Carbs
7.4
g
Fat
0.1
g

More nutrients

Fiber
1.4g
Sugar
3.4g
Sat. Fat
0.0g
Sodium
3mg
Calcium
18mg
Iron
0mg
Potassium
117mg
Magnesium
8mg
Zinc
0mg
Vitamin D
0.0mcg

Frequently Asked Questions

For consistent tracking of Onion, weigh it raw. Cooking method changes both weight and calorie density — steaming barely changes anything, but roasting with oil or frying can double the calories. A systematic review (Whitton et al., Adv Nutr 2022) found vegetables are omitted from food logs 2–85% of the time, often because people assume they are "free" calorically. While most vegetables are indeed low-calorie, the fats added during cooking are not. Log the oil, butter, or dressing separately to keep your tracking accurate.

Onion contains 1.1g protein per 100g, which is lower in protein. A 80g serving provides 0.9g protein.

Yes, Onion can support weight loss. At 40 kcal per 100g it is low in calorie density, allowing larger portions for fewer calories.

Onion can fit into a keto diet in moderate amounts. At 7.6g net carbs per 100g, smaller portions can stay within the daily limit.

Onion provides 40 kcal, 1.1g protein, 9.3g carbs, and 0.1g fat per 100g. Compare with other vegetables foods in our database to find the best option for your nutritional goals.

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80g(Standard)
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19 kcal0.9g protein

Condiments & Sauces

Ketchup

101 kcal1.0g protein

Sweeteners

Date syrup

293 kcal1.0g protein

Sweets & Desserts

Frozen novelties, fruit and juice bars

87 kcal1.2g protein

Food product photo

Vegetables

Onion

Macros per 100g

40
Calories
Protein1.1g
Fat0.1g
Carbs9.3g
Article research basis
1,316Papers Analyzed
4,654Foods in Database
100%Peer-Reviewed Sources
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Reviewed by Calibr8

Peer-reviewed data · Last updated March 19, 2026

Potassium
146mg3%
  • Magnesiumathlete
    10mg2%
  • Zincathlete
    0mg2%