Onion — Nutrition & Calories
Onion per 100g: 40 cal · 1.1g protein · 9.3g carbs · 0.1g fat · 1.7g fiber. Contains quercetin and allicin with potent anti-inflammatory and antibacterial properties.
Onion contains 40 calories per 100g serving — 1.1g protein, 9.3g carbs, 0.1g fat, 1.7g fiber, 4mg sodium. Per 100g: 40 calories. Vegan. Keto-friendly. Gluten-free. Contains quercetin and allicin with potent anti-inflammatory and antibacterial properties.
Onion Macros (per 100g)
Onion Calories by Serving Size
| Serving | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| 1 g (100g) | 40 cal | 1.1g | 9.3g | 0.1g |
| 100g | 40 cal | 1.1g | 9.3g | 0.1g |
| 200g | 80 cal | 2.2g | 18.6g | 0.2g |
| 1 cup (~240g) | 96 cal | 2.6g | 22.3g | 0.2g |
| 1 oz (28g) | 11 cal | 0.3g | 2.6g | 0.0g |
Burn Off Onion (40 calories) — Exercise Time
For a 154 lb (70 kg) person, time needed to burn 40 calories from Onion:
- Walking (3 mph)9 min
- Running (6 mph)3 min
- Cycling (moderate)4 min
- Swimming (moderate)5 min
Calculated from MET values per Compendium of Physical Activities 2024 (Ainsworth et al., updated from 2011).
Diet Compatibility
Frequently Asked Questions
How many calories are in Onion?
Onion contains 40 calories per 100g serving. That's 40 calories per 100g, or 96 calories per cup (~240g). Calorie content varies based on preparation method.
What's the protein content in Onion?
Onion has 1.1g of protein per 100g (1.1g protein per 100g). Low protein content; consider pairing with high-protein foods.
Is Onion keto-friendly?
Yes, Onion is keto-friendly. With 9.3g carbs and 0.1g fat per 100g, it fits within standard keto macros (under 20-50g carbs/day). Net carbs: 7.6g.
Is Onion suitable for vegans?
Yes, Onion is vegan. It contains no animal products. Often used in plant-based diets for flavor.
What are the macros for Onion?
Per 100g: 40 calories, 1.1g protein (11% cal), 9.3g carbs (93% cal), 0.1g fat (2% cal). Fiber: 1.7g. Sodium: 4mg.
How much Onion should I eat to lose weight?
For weight loss, Onion fits a calorie deficit if portioned. A typical 500 cal/day deficit means Onion can comprise up to 1250g as a snack, or paired with vegetables for a meal. Use our Calorie Deficit Calculator to determine your daily target.