Asparagus has about 20 calories per 100 grams, making it one of the lowest-calorie vegetables you can eat. A single medium spear weighs roughly 16 grams, so one spear comes in at around 3 calories. A typical serving of four to five spears lands somewhere between 13 and 17 calories.
Calories by Serving Size
The calorie count shifts depending on how you measure your asparagus. Here’s a quick breakdown of raw asparagus:
- 1 medium spear (16 g): about 3 calories
- Half cup, chopped (90 g): about 18 calories
- 100 grams: 20 calories
- 1 full cup, chopped (180 g): about 36 calories
These numbers are for raw asparagus. Steaming or boiling doesn’t meaningfully change the calorie count. Roasting with olive oil, on the other hand, adds roughly 40 calories per teaspoon of oil you use. A typical oven-roasted batch tossed in a tablespoon of olive oil adds about 120 calories split across the whole tray, so your individual portion picks up an extra 30 to 40 calories.
How Asparagus Compares to Other Vegetables
Even among green vegetables, asparagus sits near the bottom of the calorie scale. At 20 calories per 100 grams, it’s nearly tied with spinach (23 calories) and well below Brussels sprouts (43 calories). Watercress edges it out at just 11 calories per 100 grams, but most people eat watercress as a garnish rather than a side dish.
Asparagus also delivers a reasonable amount of protein for a vegetable: 2.2 grams per 100-gram serving. That’s comparable to spinach (2.9 g) and watercress (2.3 g), and it puts asparagus in the higher tier of vegetable protein sources. You won’t build a meal around it, but it contributes more than most people expect from a green vegetable.
What Else You Get Besides Low Calories
The real appeal of asparagus goes beyond its calorie count. A half-cup serving provides 35% of your daily value of vitamin K, which plays a central role in blood clotting and bone health. That same serving delivers 10% of your daily vitamin A and 9% of your daily folate, a B vitamin that’s especially important during pregnancy and for cell repair in general.
Asparagus is also a natural source of prebiotic fiber, the type that feeds beneficial gut bacteria. A 100-gram serving contains roughly 2 grams of fiber. That’s modest on its own, but because asparagus is so easy to eat in larger quantities without racking up calories, it’s a practical way to add fiber to a meal.
Best Ways to Keep Asparagus Low-Calorie
If you’re tracking calories closely, your cooking method matters more than the asparagus itself. Steaming, grilling, or blanching keeps the calorie count virtually identical to raw. Sautéing in butter or roasting with oil adds the most, though even then you’re looking at a side dish that rarely exceeds 60 to 80 calories per serving.
One practical tip: thicker spears and thinner spears have the same calorie density by weight. Thick spears just weigh more per spear. If a recipe calls for a specific number of spears, thicker ones will have slightly more calories simply because there’s more vegetable there. Weighing your portion gives you a more accurate count than counting individual spears.