Onion vs Kale: Nutrition Comparison
Which is healthier? Compare calories, protein, carbs, and more
Complete side-by-side nutrition comparison per 100g serving | Updated 2026
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 fewer calories (40 vs 49), more fiber (1.7g vs 1.3g), less sodium (4mg vs 28mg)making it the better choice for most health goals.
Quick Summary
Fewer Calories
Onion
40 kcal
More Protein
Kale
2.2g
More Fiber
Onion
1.7g
Less Sugar
Kale
0g
Visual Comparison
Side-by-Side Nutrition Table
Serving Size Comparison
All values above are per 100g. Here's how they compare in common serving sizes:
Onion
Kale
Diet Compatibility
Onion
Kale
When to Choose Onion
- ✓Lower in calories (40 vs 49)
- ✓More fiber (1.7g vs 1.3g)
- ✓Lower in carbs (9g vs 9g)
- ✓Lower sodium (4mg vs 28mg)
Common Uses
When to Choose Kale
- ✓Higher in protein (2.2g vs 1.1g)
- ✓Less sugar (0g vs 4.2g)
Common Uses
Onion vs Kale: Nutritional Analysis
Kale is more calorie-dense at 49 calories per 100g compared to 40 for Onion, a difference of 9 calories. On the protein front, Kale delivers more with 2.2g per 100g versus 1.1g, which matters for muscle maintenance, satiety, and overall metabolic health. These differences become meaningful when you consider how each food fits into your daily dietary pattern rather than looking at any single nutrient in isolation.
Macronutrient Breakdown
The macronutrient profiles of Onion and Kale tell different nutritional stories. Onion provides 9g of carbohydrates, 0.1g of fat, and 1.7g of fiber per 100g, while Kale contains 9g carbs, 0.9g fat, and 1.3g fiber. The higher fiber content in Onion supports digestive health, helps regulate blood sugar after meals, and contributes to longer-lasting satiety. Sugar content also differs: Onion contains 4.2g while Kale has 0g per 100g. Lower sugar options are generally preferable for blood sugar management and dental health.
Key Takeaways
- For weight management: Onion is the lower-calorie choice at 40 cal/100g, making it more suitable for calorie-controlled diets.
- For muscle building: Kale provides more protein (2.2g/100g), supporting muscle repair and growth.
- For sustained energy: Onion offers more fiber (1.7g/100g), which slows digestion and provides steadier energy release.
- Overall: Neither food is universally "better" than the other. The right choice depends on your specific nutritional goals, meal context, and dietary preferences. Both can play a role in a balanced diet.
Frequently Asked Questions
Which has more calories, Onion or Kale?
Kale has more calories with 49 kcal per 100g, compared to Onion with 40 kcal. That's a difference of 9 calories per 100g serving.
Is Onion healthier than Kale?
Based on our nutritional analysis, Onion is generally the healthier choice, winning in 3 out of 5 key nutritional categories. Onion has 40 calories, 1.1g protein, and 1.7g fiber per 100g. However, the best choice depends on your specific dietary goals.
What is the protein difference between Onion and Kale?
Kale has more protein with 2.2g per 100g, compared to Onion with 1.1g. Kale provides 1.1g more protein per 100g serving.
Which is better for weight loss, Onion or Kale?
For weight loss, Onion is the better choice with only 40 calories per 100g compared to 49 calories in Kale. Onion also offers 1.7g of fiber per 100g, which helps you feel fuller longer.
Does Onion or Kale have fewer carbs?
Onion and Kale have the same carbohydrate content at 9g per 100g.
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About Our Data
All nutrition data in this comparison is sourced from the USDA FoodData Central, the official food composition database maintained by the U.S. Department of Agriculture. Values are based on 100g servings for accurate comparison.
Health Disclaimer: This comparison is for informational purposes only and is not intended as medical or dietary advice. Nutritional needs vary by individual. The best food choice depends on your personal health goals, dietary requirements, and preferences. Consult a healthcare provider or registered dietitian for personalized nutrition guidance.