Zucchini is one of the lowest-calorie vegetables you can eat. A whole medium zucchini (196g) contains just 33 calories, according to the USDA. That works out to roughly 17 calories per 100 grams, putting it in the same range as cucumbers and lettuce.
What Makes Zucchini So Low in Calories
Zucchini is almost entirely water. That high water content is the main reason the calorie count stays so low, even when you eat a large portion. A single medium zucchini also provides 2 grams of dietary fiber, which adds bulk without adding calories. Together, the water and fiber create a filling sensation that can reduce the urge to reach for higher-calorie foods afterward.
The carbohydrate content is minimal, giving zucchini a low glycemic index. That means it has very little impact on blood sugar levels, which matters if you’re watching your carb intake or managing blood sugar.
How Cooking Changes the Numbers
Raw zucchini has about 1 gram of fiber per 100 grams. Frozen zucchini that’s been cooked and boiled comes in slightly higher at 1.3 grams of fiber per 100 grams. The calorie difference between raw and cooked zucchini is negligible as long as you’re not adding oil, butter, or heavy sauces.
Where cooking really shifts the calorie count is in preparation. A cup of zucchini sautéed in a tablespoon of olive oil picks up about 120 extra calories from the oil alone. Grilling, roasting with a light spray, or air frying keeps the total much closer to that baseline 33 calories per medium zucchini. Spiralized raw zucchini (“zoodles”) used as a pasta substitute stays at the lowest end of the spectrum.
Zucchini vs. Other Low-Calorie Vegetables
For context, here’s how zucchini stacks up against other popular vegetables per 100 grams:
- Zucchini: ~17 calories
- Cucumber: ~15 calories
- Celery: ~14 calories
- Bell pepper: ~26 calories
- Broccoli: ~34 calories
- Sweet potato: ~86 calories
Yellow summer squash and green zucchini are nutritionally very similar. Both are high-water, low-calorie summer squashes with comparable vitamins and minerals, so you can swap them freely without changing your calorie math in any meaningful way.
Why It Works for Weight Management
Nutritionists describe zucchini as a “low energy density” food, meaning it delivers very few calories relative to its weight and volume. This is one of the most practical advantages for anyone trying to lose or maintain weight. You can eat a large, visually satisfying plate of food without consuming many calories.
The fiber content, while modest at 2 grams per medium zucchini, helps slow digestion and keeps your appetite in check between meals. Pairing zucchini with a protein source (grilled chicken, eggs, beans) amplifies this effect because protein and fiber together are the most satiating combination in a meal.
Easy Ways to Add More Zucchini
Because zucchini has a mild flavor and soft texture when cooked, it blends into dishes without dramatically changing the taste. Grating it into pasta sauces, soups, or even baked goods like muffins lets you increase the volume of a meal while keeping calories low. Slicing it into rounds and roasting at high heat concentrates the flavor and gives you a satisfying side dish for under 50 calories per cup.
Zucchini noodles remain one of the simplest swaps for traditional pasta. A full plate of zoodles tops out around 30 to 40 calories before sauce, compared to roughly 200 calories for a cup of cooked spaghetti. Even replacing half the pasta with zoodles cuts the calorie load of the dish significantly while keeping the portion size the same.