You're standing in the produce aisle, holding a vegetable that looks more like a baton than a snack. It’s firm, green, and—if you picked a good one—about six inches long. You're wondering about the calories in a small zucchini because, let's be honest, tracking every bite can feel like a full-time job. Most people overthink it. They worry that the sautéing or the "zoodling" is going to rack up a massive caloric debt.
It won't.
Zucchini is basically nature’s way of giving us volume without the baggage. It is 95% water. Think about that for a second. When you eat a zucchini, you are mostly eating structured water held together by a little bit of cellulose and a surprising amount of nutrients.
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The actual number: Calories in a small zucchini
If we’re looking at a standard "small" zucchini—roughly 6 inches long and weighing about 118 grams—you are looking at approximately 20 calories.
Twenty. That is practically a rounding error in most daily diets.
But wait. Size is subjective. One person's "small" is another person's "medium." According to the USDA FoodData Central database, 100 grams of raw zucchini contains exactly 17 calories. If you happen to grab a slightly larger one that hits 150 grams, you're still only at 25 calories. It’s hard to mess this up.
Why is it so low? It’s because zucchini lacks the starch found in its cousins, like butternut squash or pumpkins. While a cup of cubed butternut squash might hit 60 or 80 calories, zucchini stays in the basement. It’s the ultimate "filler" food. You can bulk up a pasta sauce, a cake batter, or a stir-fry with three whole zucchinis and you’ve barely added the caloric equivalent of a single large apple.
Don't ignore the nutrition behind the numbers
Counting the calories in a small zucchini is only half the story. If you only look at the 20 calories, you miss why it’s actually on your plate.
Zucchini is a stealthy source of potassium. We usually think of bananas for potassium, but zucchini holds its own. Potassium is critical for managing blood pressure because it helps your body ease the tension in your blood vessel walls. It also packs a punch of Vitamin C and Vitamin B6.
And then there's the skin.
Never peel it. Seriously. Most of the antioxidants, specifically carotenoids like lutein and zeaxanthin, live in that dark green skin. These are the same compounds found in kale and spinach that protect your eyes from blue light damage and age-related macular degeneration. If you peel the zucchini to make it "prettier" in a recipe, you’re tossing the most valuable parts into the compost bin. Keep the skin. Your eyes will thank you later.
How cooking changes the math
Raw zucchini is a crunchy, slightly bitter experience. It’s fine in salads. But most of us cook it. This is where people get tripped up on their calorie tracking.
When you cook a zucchini, it loses water. It shrinks. A giant pile of raw zoodles turns into a tiny clump of cooked noodles in about three minutes. The calories don't change, but the density does. If you measure one cup of cooked zucchini, you’re actually eating about two "small" zucchinis. So, a cup of cooked, sliced zucchini is closer to 35 or 40 calories.
Still low? Yes.
But the real "danger" is the fat. Zucchini is a sponge. It’s porous. If you toss that small zucchini into a pan with two tablespoons of olive oil, you aren't eating a 20-calorie snack anymore. You're eating a 260-calorie side dish.
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- Steaming: Adds 0 calories.
- Grilling: Adds 0 calories (if you use a non-stick spray).
- Roasting: Usually involves oil, so add about 40-100 calories depending on your pour.
- Air Frying: The middle ground. High crunch, low added fat.
I’ve seen people get frustrated because they eat "clean" veggies but don't lose weight. Often, it's the "healthy" olive oil drizzle that turns a light vegetable into a calorie-dense bomb. Be mindful of the soak.
Why "Zoodling" actually works for weight loss
We’ve all seen the spiralizers. They were the "it" kitchen gadget a few years ago for a reason. Replacing pasta with zucchini is one of the few "diet hacks" that actually makes physiological sense.
Standard spaghetti has about 220 calories per cup.
Zucchini noodles have about 20 calories per cup.
That is a 200-calorie difference per serving. If you make that swap twice a week, you've cut 400 calories without really changing the volume of food you’re eating. Your brain sees a full plate. Your stomach feels the weight of the water and fiber. You feel full.
There’s a concept in nutrition called Energy Density. Dr. Barbara Rolls from Penn State University has spent decades researching this. Her findings are pretty simple: people tend to eat a consistent weight of food each day, regardless of the calories. By choosing foods with low energy density—like zucchini—you can eat the same "weight" of food while drastically dropping your caloric intake. It’s the closest thing to a "free lunch" in the nutrition world.
Common misconceptions about zucchini
A lot of people think zucchini is "empty" because it’s so watery. That’s a mistake.
It’s actually quite rich in soluble fiber. This is the stuff that feeds your gut bacteria. When your gut biome is happy, your inflammation levels drop and your metabolism tends to run smoother.
Another weird myth? That big zucchinis are better.
Nope.
The giant, forearm-sized zucchinis you see at farmers' markets are actually less flavorful and have a woodier texture. They also have more seeds, which means more "void space." The calories in a small zucchini are more concentrated in flavorful flesh. Stick to the small or medium ones. They taste better, they cook faster, and the nutrient-to-calorie ratio is actually superior.
Practical ways to use that small zucchini today
You don't need to be a chef to make this work. Honestly, the simpler the better.
- The Grate Trick: Grate a small zucchini into your oatmeal. I know, it sounds weird. But it adds volume and moisture without changing the taste. Add some cinnamon and a little maple syrup, and you've got "zoats." It's a high-volume breakfast for very few calories.
- The Smoothie Filler: Throw half a raw zucchini into your blender. It makes the smoothie creamier than ice does, and you won't taste it over the protein powder or fruit.
- The Quick Sauté: Slice it thin, throw it in a pan with garlic and a splash of soy sauce. Don't overcook it. You want a little bite left.
Zucchini is the ultimate chameleon. It takes on the flavor of whatever you cook it with. If you cook it with bacon, it tastes like bacon. If you cook it with lemon and herbs, it tastes fresh and bright.
Actionable Next Steps
If you want to start using zucchini to manage your weight or improve your digestion, start small.
- Buy three small zucchinis this week. Not the big ones.
- Keep the skin on whenever you prep them to maximize the fiber and antioxidants.
- Swap one carb-heavy side (like rice or potatoes) for a sautéed zucchini.
- Track the oil. If you're counting calories, measure your cooking oil with a spoon rather than "eyeballing" the pour.
Stop worrying about the 20 calories. Focus instead on the fact that you're adding volume, hydration, and micronutrients to your day. It’s one of the few foods where you can truly eat as much as you want without a second thought.