Onion vs Tomato

Complete nutrition comparison per 100g serving

Which is Healthier?

Onion is generally healthier

Onion comes out ahead in this comparison, winning in 3 out of 5 key nutritional categories. It has more protein (1.1g vs 0.9g), more fiber (1.7g vs 1.2g), less sodium (4mg vs 5mg)making it the better choice for most health goals.

Quick Summary

Fewer Calories

Tomato

18 kcal

More Protein

Onion

1.1g

More Fiber

Onion

1.7g

Less Sugar

Tomato

2.6g

Visual Comparison

Caloriesper 100g
Onion
40
Tomato
18
Proteinper 100g
Onion
1.1g
Tomato
0.9g
Carbohydratesper 100g
Onion
9g
Tomato
4g
Fatper 100g
Onion
0.1g
Tomato
0.2g

Side-by-Side Nutrition Table

NutrientOnionTomatoDifference
Calories40kcal18kcal+22.0kcal
Protein1.1g0.9g+0.2g
Carbohydrates9g4g+5.0g
Fat0.1g0.2g-0.1g
Fiber1.7g1.2g+0.5g
Sugar4.2g2.6g+1.6g
Sodium4mg5mg-1.0mg

Serving Size Comparison

All values above are per 100g. Here's how they compare in common serving sizes:

Onion

Per 100g:40 calories
Per cup (150g):60 calories
Per serving (85g):34 calories

Tomato

Per 100g:18 calories
Per cup (150g):27 calories
Per serving (85g):15 calories

Diet Compatibility

Onion

Low-CarbLow-CalorieVeganVegetarianPaleoLow-Sodium

Tomato

Low-CarbLow-CalorieVeganVegetarianPaleoLow-Sodium

When to Choose Onion

  • Higher in protein (1.1g vs 0.9g)
  • More fiber (1.7g vs 1.2g)
  • Lower sodium (4mg vs 5mg)

Common Uses

SaladsStir-friesRoasted sidesSoups
View full Onion nutrition →

When to Choose Tomato

  • Lower in calories (18 vs 40)
  • Lower in carbs (4g vs 9g)
  • Less sugar (2.6g vs 4.2g)

Common Uses

SaladsStir-friesRoasted sidesSoups
View full Tomato nutrition →