Grapefruit Calories & Nutrition Facts
Very low GI citrus fruit shown to support insulin sensitivity and weight loss.
Quick answer
How many calories are in Grapefruit?
Grapefruit has 42 calories per 100g. A 0.5 fruit (3-3/4" dia) (123g) has about 52 calories. It is a low-calorie food, with most calories coming from carbs.
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Practical Portion Guide for Grapefruit
| Portion | Calories | Protein | Carbs | Net carbs | Fat |
|---|---|---|---|---|---|
| 0.5 fruit (3-3/4" dia) (123g) | 52 kcal | 1.0g | 13.5g | 11.6g | 0.1g |
| 1 cup sections, with juice (230g) | 97 kcal | 1.8g | 25.3g | 21.6g | 0.2g |
| 1 NLEA serving (154g) | 65 kcal | 1.2g | 16.9g | 14.5g | 0.2g |
| 100g USDA reference | 42 kcal | 0.8g | 11.0g | 9.4g | 0.1g |
Fruit portions are usually larger than 100g, so use the serving calculator when counting total calories or net carbs (9.4g per 100g).
% Daily Value: 0.5 fruit (3-3/4" dia) (123g) vs 100g
Percent Daily Values use the FDA reference amounts for adults (protein 50g, fiber 28g, carbohydrate 275g, fat 78g, sodium 2,300mg, cholesterol 300mg, potassium 4,700mg). The FDA label guide treats 20% DV or more per serving as high and 5% DV or less as low. Potassium comes from USDA FoodData Central FDC ID 174673 (Grapefruit, raw, pink and red, all areas); the other values are this page's 100g reference scaled to the portion.
| Nutrient | Per 100g | % DV | 0.5 fruit (3-3/4" dia) (123g) | % DV |
|---|---|---|---|---|
| Protein | 0.8g | 2% | 1g | 2% |
| Dietary fiber | 1.6g | 6% | 2g | 7% |
| Total carbohydrate | 11g | 4% | 13.5g | 5% |
| Total fat | 0.1g | 0% | 0.1g | 0% |
| Sodium | 0mg | 0% | 0mg | 0% |
| Cholesterol | 0mg | 0% | 0mg | 0% |
| Potassium (USDA) | 135mg | 3% | 166mg | 4% |
Source: FDA Daily Values (21 CFR 101.9), checked September 17, 2026. USDA record: FDC ID 174673.
Where Grapefruit Ranks (USDA Comparisons)
Grapefruit appears in these ranked USDA comparisons built from the same 100g dataset used on this page.
Serving Size Calculator
Macros Breakdown (per 100g)
Diet Suitability
Glycemic Index: 25 (Low)
How Grapefruit Fits Into a Diet
Grapefruit works best as a fiber-rich carbohydrate source for snacks, breakfast bowls, or pre-workout meals.
Pair fruit with protein or fat, such as yogurt, cottage cheese, nuts, or seeds, when you want slower digestion and better satiety.
Fruit size, ripeness, and variety can change water and sugar content, so gram-based tracking is more reliable than counting pieces.
Plan Around Grapefruit
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Macro Calculator
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Keto Diet Guide
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Calorie Calculator
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Compare Grapefruit With Similar Fruits
Use this comparison when choosing a serving. Calories alone do not tell the full story: protein, fiber, fat, sodium, and realistic portion size determine whether a food fits your plan.
| Food | Calories | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| Grapefruit | 42 kcal | 0.8g | 11g | 0.1g | 1.6g |
| Apple | 52 kcal | 0.3g | 14g | 0.2g | 2.4g |
| Banana | 89 kcal | 1.1g | 23g | 0.3g | 2.6g |
| Orange | 47 kcal | 0.9g | 12g | 0.1g | 2.4g |
| Mango | 60 kcal | 0.8g | 15g | 0.4g | 1.6g |
| Strawberry | 32 kcal | 0.7g | 7.7g | 0.3g | 2g |
All comparison values use each food's 100-unit reference so foods can be compared on the same basis.
Vitamins & Minerals
Vitamins
Minerals
Complete Nutrition Facts (per 100g)
% DV = percent of the FDA Daily Value for a 2,000-calorie diet, per 100g. Total sugars have no Daily Value; the FDA value applies to added sugars only.
Methodology & Nutrition Data Sources
How we calculate nutrition data for Grapefruit: Calorie and macronutrient values are standardized reference profiles, generally based on USDA FoodData Central entries where available, then scaled to the serving you choose. Entries may come from different FDC data types or releases, and brand or preparation differences can change the numbers.
- Calorie and macronutrient data sourced from the USDA FoodData Central , the federal food composition database used as the main reference where a matching entry exists.
- Daily Value context: for % DV comparisons, use the FDA Daily Value reference amounts for a 2,000 calorie diet (21 CFR 101.9).
- Dietary reference intakes (DRI) for vitamins and minerals are available in the National Academies Dietary Reference Intake tables for further reading; this page does not calculate DRI percentages.
- Glycemic index values are approximate listed values; GI varies by variety, ripeness, and preparation, so compare with the Harvard Health Glycemic Index Reference and the University of Sydney GI database.
- Dietary guidelines context from the HHS/USDA Dietary Guidelines for Americans 2020–2025 , the federal evidence-based nutrition guidance.
Authoritative nutrition data sources:
- USDA FoodData Central, comprehensive food composition database
- FDA Nutrition Facts Label rules, % Daily Value methodology
- NIH Office of Dietary Supplements, vitamin and mineral research
- CDC Nutrition, Public Health Guidance, chronic disease and diet
- HHS/USDA Dietary Guidelines 2020–2025, federal nutrition recommendations
- Harvard T.H. Chan School of Public Health, The Nutrition Source, evidence-based dietary guidance
Nutrition Disclaimer: Calorie and nutrient values are generally based on USDA reference data and may vary by brand, preparation method, ripeness, and cooking technique. These values are for informational purposes only and should not replace personalized dietary advice from a registered dietitian. Individuals with medical conditions should consult a healthcare provider before making significant dietary changes.
Reviewed by Priya Lindqvist · Last updated September 17, 2026 · Values may not reflect the newest USDA FoodData Central release
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Frequently Asked Questions
How many calories are in 0.5 fruit (3-3/4" dia) Grapefruit?
0.5 fruit (3-3/4" dia) (123g) of Grapefruit has about 52 calories, 1.0g protein, 13.5g carbohydrates, 2.0g fiber, and 0.1g fat. The 123g portion weight is the USDA FoodData Central household measure for FDC ID 174673 (Grapefruit, raw, pink and red, all areas), scaled from the 100g reference values.
Is Grapefruit high in protein?
Grapefruit has 0.8g protein per 100g, which is 2% of the 50g FDA Daily Value. 0.5 fruit (3-3/4" dia) (123g) supplies about 1.0g, or 2% DV. Under the FDA label guide (20% DV or more per serving is high, 5% or less is low), that serving counts as a low-protein serving.
Is Grapefruit a good source of potassium?
USDA FoodData Central lists 135mg potassium per 100g for Grapefruit, raw, pink and red, all areas (FDC ID 174673), which is 3% of the 4,700mg Daily Value. 0.5 fruit (3-3/4" dia) (123g) provides about 166mg, or 4% DV, a low contribution by the FDA 5% guide.
How many calories are in Grapefruit?
Grapefruit contains 42 calories per 100g serving. Using general 4-4-9 calorie factors, that is roughly 3 calories from protein, 44 calories from carbohydrates, and 1 calories from fat; these estimates may not add up exactly to the listed total.
Is Grapefruit good for weight loss?
Yes, Grapefruit is excellent for weight loss with only 42 calories per 100g. It is low in calories and can help you feel satisfied while maintaining a calorie deficit.
How much protein is in Grapefruit?
Grapefruit contains 0.8g of protein per 100g. This is a relatively low protein food; consider pairing it with higher protein sources.
What serving size should I track for Grapefruit?
Track Grapefruit by grams when precision matters. A practical starting point is 0.5 fruit (3-3/4" dia) (123g), which is about 52 calories. For packaged, restaurant, fried, sauced, or sweetened versions, use the product label because brand formulas can differ from the plain reference.
Is Grapefruit keto-friendly?
Yes, Grapefruit is keto-friendly with only 11g of carbohydrates per 100g. It fits well within the typical keto macro limits of 20-50g net carbs per day.
Is Grapefruit good for diabetics?
Grapefruit may fit a diabetes meal plan with a listed glycemic index of 25, but the useful decision is the actual portion, total carbohydrates, added sugar, and the rest of the meal. People using diabetes medication should follow personalized clinical guidance.
What vitamins and minerals are in Grapefruit?
Calorique's food profile lists vitamins C, A, B1 and minerals including Potassium, Magnesium, Calcium for Grapefruit. These are general highlights, not measured amounts or a "good source" rating; check USDA FoodData Central or the product label for exact micronutrient values.
Where does Calorique get nutrition data for Grapefruit?
Calorique standardizes Grapefruit nutrition values per 100g using USDA FoodData Central reference fields where available, then scales the data into realistic serving sizes. FDA Nutrition Facts methodology and authoritative nutrition references are used for context. This page was last reviewed September 17, 2026.
Related Calculators
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47 cal · 0.9g protein per 100g
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Strawberry
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