Calories in Grapefruits: Nutrition Facts & Serving Sizes
Per 1 cup sections, with juice (230g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
Grapefruit is a tart citrus fruit that packs serious nutrition into very few calories. Half a grapefruit (118g) contains just 44 calories, making it one of the lowest-calorie fruits you can eat. Per 100g you get 37 calories, 0.9g protein, 9.1g carbs, and only 0.1g fat. The standout micronutrient is vitamin C at 33.3mg per 100g, which covers a solid chunk of your daily needs in a single serving. Grapefruit is also a source of potassium at 143mg per 100g, supporting muscle function and hydration. The natural tartness comes from organic acids that may help with appetite control. Whether you eat it plain, section it into a bowl, or squeeze it for fresh juice, grapefruit is a smart low-calorie option when you want something sweet but need to stay on track with your macros.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 cup sections, with juice (230g) | 85.1 | 2.1g | 20.9g | 0.2g | 0g |
| 0.5 fruit (3-3/4" dia) (118g) | 43.7 | 1.1g | 10.7g | 0.1g | 0g |
| 100g | 37 | 0.9g | 9.1g | 0.1g | 0g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 37 | 2% |
| Protein | 0.9g | 2% |
| Total Fat | 0.1g | |
| Total Carbohydrates | 9.1g | 3% |
| Dietary Fiber | 0g | |
| Sugars | 0g | |
| Sodium | 0mg |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calcium | 12mg | 1% |
| Iron | 0.1mg | 1% |
| Potassium | 143mg | 3% |
| Vitamin C | 33.3mg | 37% |
| Magnesium | 9mg | 2% |
| Phosphorus | 12mg | 1% |
| Zinc | 0.1mg | 1% |
| Folate | 12mcg | 3% |
| Niacin (B3) | 0.3mg | 2% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Grapefruits
Grapefruit earns its reputation as a diet-friendly fruit. At just 37 calories per 100g, it delivers serious volume for minimal caloric cost, which is key when you are trying to stay full on a cut. The high water content helps with satiety, meaning you can eat a larger portion without blowing your calorie budget.
The vitamin C content (33.3mg per 100g) supports collagen synthesis, immune function, and recovery from training. If you are putting in hard sessions at the gym, adequate vitamin C intake matters more than most people realize. It also acts as an antioxidant, helping to manage oxidative stress from intense exercise.
Grapefruit contains a flavonoid called naringenin, which has been studied for its potential effects on metabolism and insulin sensitivity. While the research is ongoing, the overall nutritional profile makes grapefruit a solid addition to a fat-loss diet. The potassium content (143mg per 100g) also supports heart health and helps counter the effects of a high-sodium diet. For those focused on body composition, grapefruit is a high-volume, low-calorie food that checks multiple boxes.
Dietary Considerations
Grapefruit is naturally vegan, gluten-free, and dairy-free, making it compatible with virtually every eating style. At 37 calories per 100g, it fits comfortably into calorie-deficit diets and weight loss plans. The carb count of 9.1g per 100g is moderate for a fruit, so strict keto followers may want to limit portion size, but it works well for low-carb and flexible dieting approaches. There is no added sugar, no sodium, and essentially no fat. One important note: grapefruit interacts with certain medications including some statins and blood pressure drugs. If you are on any prescription medication, check with your doctor before making grapefruit a daily staple.
Daily Intake (100g)
100g of grapefruit provides 2% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in a grapefruit?
Half a grapefruit (118g) contains 44 calories. A full cup of grapefruit sections with juice (230g) contains about 85 calories. Per 100g, grapefruit has 37 calories.
Is grapefruit good for weight loss?
Yes, grapefruit is excellent for weight loss. At just 37 calories per 100g, it is one of the most volume-efficient fruits you can eat. Its high water content and tartness help with satiety, and it provides vitamin C and potassium with minimal impact on your calorie budget.
How much protein is in grapefruit?
Grapefruit has 0.9g of protein per 100g. Half a grapefruit provides about 1.1g of protein. It is not a meaningful protein source, so pair it with eggs or Greek yogurt for a complete breakfast.
Is grapefruit keto-friendly?
Grapefruit has 9.1g of carbs per 100g, which is moderate. Half a grapefruit adds about 10.7g of carbs. Strict keto dieters may want to limit it, but for low-carb and flexible dieting it fits in well.
What vitamins are in grapefruit?
Grapefruit is especially high in vitamin C at 33.3mg per 100g. It also contains folate (12mcg), potassium (143mg), and small amounts of calcium, magnesium, and niacin.
Does grapefruit interact with medications?
Yes. Grapefruit contains compounds that inhibit an enzyme used to metabolize many medications, including some statins, blood pressure drugs, and others. If you take prescription medication, check with your doctor before eating grapefruit regularly.
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