Calories in Fennel: Nutrition Facts & Serving Sizes
Per 1 cup, sliced (87g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
Fennel is a crunchy, aromatic vegetable with a mild anise-like flavor. Both the bulb and fronds are edible, and it can be eaten raw, roasted, or braised. At just 31 calories per 100g and 27 calories per cup sliced, it is a very low-calorie vegetable with a good fiber-to-carb ratio. A full fennel bulb (234g) contains only 73 calories alongside 7.3g of fiber, making it an excellent high-volume food for cutting phases. Fennel provides 414mg of potassium per 100g, 62.8mcg of vitamin K, and 12mg of vitamin C. The crunchy texture and distinctive flavor make it a useful addition to salads, slaws, and roasted vegetable dishes. It is a practical way to increase meal volume without adding significant calories.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 bulb (234g) | 72.5 | 2.8g | 17.1g | 0.5g | 7.3g |
| 1 cup, sliced (87g) | 27 | 1g | 6.4g | 0.2g | 2.7g |
| 100g | 31 | 1.2g | 7.3g | 0.2g | 3.1g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 31 | 2% |
| Protein | 1.2g | 2% |
| Total Fat | 0.2g | |
| Saturated Fat | 0.1g | 1% |
| Total Carbohydrates | 7.3g | 3% |
| Dietary Fiber | 3.1g | 11% |
| Sugars | 3.9g | 8% |
| Sodium | 52mg | 2% |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Saturated Fat | 0.1g | 0% |
| Calcium | 49mg | 4% |
| Iron | 0.7mg | 4% |
| Potassium | 414mg | 9% |
| Vitamin A | 48mcg | 5% |
| Vitamin C | 12mg | 13% |
| Magnesium | 17mg | 4% |
| Phosphorus | 50mg | 4% |
| Zinc | 0.2mg | 2% |
| Selenium | 0.7mcg | 1% |
| Folate | 27mcg | 7% |
| Niacin (B3) | 0.6mg | 4% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Fennel
Fennel is a low-calorie vegetable with a surprisingly strong micronutrient profile. The potassium content at 414mg per 100g is higher than many common vegetables and supports electrolyte balance, muscle contraction, and blood pressure regulation. If you train hard and sweat frequently, getting adequate potassium from whole foods like fennel matters.
Vitamin K at 62.8mcg per 100g is significant for bone health. Consistent vitamin K intake has been linked to greater bone mineral density and reduced fracture risk. For those lifting heavy weights and putting high compressive loads on their bones, this is a relevant nutrient.
Fennel is a good source of dietary fiber at 3.1g per 100g. A full bulb provides 7.3g of fiber at only 73 calories, which is an efficient way to hit fiber targets without adding calories. Adequate fiber intake is consistently linked to better body composition, satiety, and gut health.
Fennel contains phytochemicals including anethole, the compound responsible for its distinctive anise flavor. Anethole has demonstrated anti-inflammatory and antioxidant properties in cellular studies, though human trials remain limited.
Vitamin C at 12mg per 100g contributes to collagen synthesis, which supports joint and connective tissue health, particularly relevant for athletes managing heavy training loads.
Dietary Considerations
Fennel is naturally vegan, gluten-free, and dairy-free. It is suitable for paleo diets and low-fat diets. While fennel is low in carbs relative to other vegetables at 7.3g per 100g, the fiber content of 3.1g brings the net carbs to approximately 4.2g per 100g, which is acceptable on keto in moderate portions. Fennel is virtually fat-free at 0.2g per 100g. It contains no cholesterol or added sugars. Fennel seed (a spice) is different from fennel bulb and has a more concentrated flavor profile. For weight loss, fennel's low calorie density and high fiber make it ideal for increasing meal volume and satisfaction.
Daily Intake (100g)
100g of fennel provides 2% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in fennel?
Fennel contains 31 calories per 100g. A sliced cup serving (87g) has 27 calories, and a full fennel bulb (234g) has about 73 calories. It is one of the lowest-calorie vegetables available.
Is fennel good for weight loss?
Yes. Fennel is excellent for weight loss. At 31 calories per 100g with 3.1g of fiber, it adds significant volume and crunch to meals without impacting calorie targets. The fiber also helps with satiety between meals.
How much protein in fennel?
Fennel has 1.2g of protein per 100g. Like most vegetables, it is not a primary protein source but contributes to overall daily intake. A full bulb provides 2.8g of protein.
Is fennel keto-friendly?
Fennel can fit into a keto diet in moderate portions. With 7.3g of carbs and 3.1g of fiber per 100g, the net carbs are roughly 4.2g per 100g. A cup-sized serving has about 3.7g of net carbs.
What does fennel taste like?
Fennel has a mild, slightly sweet anise or licorice flavor when raw. The flavor becomes milder and more savory when roasted or braised. If you dislike strong licorice flavors, cooked fennel is much more approachable.
How do you eat fennel?
Slice the bulb thinly for salads, roast wedges with olive oil and salt, braise it in broth as a side dish, or use it raw in slaws. The fronds can be used as an herb garnish similar to dill. The stalks are tougher and better suited for soups and stocks.
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