Onions - How Many Calories?

Reviewed by Dyt. Şeyda Ertaş, Registered Dietitian Last reviewed: May 16, 2026

Onions

110 gr
Onions image
44kcal
Carbohydrate10.23 gr %88
Protein1.21 gr %10
Fat0.11 gr %2

Onions Nutrition Values

Nutrients100 gr1 1 Medium Onion
Calories(kcal)4044
Carbohydrate (g)9.310.23
Protein (g)1.11.21
Fat (g)0.10.11
Fiber (g)1.71.87
Cholesterol (mg)00
Sodium (mg)44.4
Potassium (mg)146160.6
Calcium (mg)2325.3
Iron (mg)0.20.22
Vitamin A (IU)00
Vitamin C (mg)7.48.14

Nutritional values are based on the USDA database. Natural variations may occur; this information is for informational purposes only and does not constitute medical advice.

Dietitian's Tips for Consuming Onions

  • Metabolic Effect: Onions contain quercetin and flavonoid compounds that may positively influence insulin sensitivity. Regular consumption can contribute to more balanced blood sugar levels throughout the day.
  • Consumption Recommendation: Eating half to one medium onion per day is generally considered an appropriate amount for most adults. Consuming onions raw preserves higher bioavailability, making them a smart addition to salads and fresh dishes.
  • Caution: Individuals with acid reflux or irritable bowel syndrome may experience discomfort due to onions' high fructooligosaccharide content. Opting for cooked onions and keeping portion sizes small can help minimize digestive issues.
  • Exercise: The natural nitrates found in onions may improve oxygen efficiency in muscles, supporting endurance performance during physical activity. Adding onions to pre-workout meals can be a beneficial strategy, especially for prolonged exercise sessions.