Per 100 g, Spinach has 23 calories and 2.9 g of protein, while Kale has 35 calories and 2.9 g. Spinach is the lighter choice, 12 kcal fewer per 100 g. Protein is the same for both.
| Per 100 g | Spinach | Kale |
|---|---|---|
| Calories | 23 kcal | 35 kcal |
| Protein | 2.9 g | 2.9 g |
| Carbs | 3.6 g | 4.4 g |
| Fat | 0.4 g | 1.5 g |
| Fiber | 2.2 g | 4.1 g |
Spinach for fewer calories; protein is a tie.
Both columns are USDA FoodData Central numbers — the same sourced data Joules logs from, rather than the crowd-sourced entries that make many trackers disagree with each other.
Per 100 g, Spinach has 23 calories and Kale has 35. Spinach is lower by 12 kcal. Compare per 100 g first, then scale to your actual portion.
Per 100 g, Spinach has 2.9 g of protein and Kale has 2.9 g. They are the same.
Neither is off-limits. Fewer calories per 100 g gives you more room in a deficit, but portion size and the rest of your day matter more than the swap itself. Log whichever you actually eat and watch your daily total.
Both foods come from USDA FoodData Central (SR Legacy): FDC ID 168462 for Spinach and 168421 for Kale, taken per 100 g so the comparison is like-for-like.
Snap a photo of Spinach or Kale in Joules and the calories and macros are logged for you — from the same USDA data.
Get JoulesA note on accuracy: calculators like this one provide estimates based on population-level formulas — your real needs vary with genetics, muscle mass, medical conditions, and more. Results are for information only and are not medical advice, a diagnosis, or a prescription. Talk to a doctor or registered dietitian before making significant changes to your diet or exercise, especially if you have a health condition, are pregnant, or are under 18.
Nutrition data: USDA FoodData Central, FDC ID 168462 · FDC ID 168421 (SR Legacy), per 100 g. Both entries are compared on the same basis.
