All Foods
Onion vs Tomato
Calories, macronutrients and nutrition facts compared side by side (per 100g).
Nutrition Comparison
| Per 100g | Onion | Tomato |
|---|---|---|
| Calories | 40kcal | 18kcal |
| Protein | 1.1g | 0.9g |
| Carbs | 9.3g | 3.9g |
| Fat | 0.1g | 0.2g |
| Fiber | 1.7g | 1.2g |
| Sugar | 4.2g | 2.6g |
| Sodium | 4mg | 5mg |
Green marks the more favorable value (fewer calories/sugar/sodium, more protein/fiber).
Key Takeaways
- Tomato has 22 fewer calories per 100g than Onion (122% less).
- Onion delivers more protein (1.1g vs 0.9g per 100g).
- Onion has more fiber (1.7g vs 1.2g).
- Onion contains less fat (0.1g vs 0.2g).
- Tomato has less sugar (2.6g vs 4.2g).
Onion
Onions are low in calories and a notable source of quercetin, an antioxidant flavonoid, plus prebiotic fibers that feed gut bacteria. Their sulfur compounds — released when chopped — are being studied for cardiovascular benefits.
View Onion nutrition →Tomato
Tomatoes are the richest dietary source of lycopene — a carotenoid linked in observational studies to lower risk of prostate cancer and cardiovascular disease. Cooking and pairing with fat (olive oil) substantially increases lycopene bioavailability.
View Tomato nutrition →Track Onion & Tomato in Kairo
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