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Portions and preparation · USDA nutrition

Grapefruit calories per cup: 76–90 across all 2 named USDA examples

Across all 2 named USDA examples, a cup contains 76–90 calories. Their listed weights span 180–250 g, so each calorie value is calculated from that example's own gram weight and published calories per 100 g.

Portion calculator

Estimate your portion

Choose a source measure or enter the weight you ate.

Preparation and portion

Named measures come from this exact source record.

Estimated for 125 g

45calories

Grapefruit, canned

Protein
0.7 g
Carbs
11.4 g
Fat
0.1 g

These values scale the selected reference food by weight. Ingredients, preparation, and portion size can change your meal’s estimate.

FoodData Central Survey Foods (FNDDS) · FDC 2709166 Full nutrition profile →

Compare all 2 food records, nutrition tables and USDA sources

The 2 exact records in this guide report 45–65 calories in the records' own listed source servings and 36–42 calories per 100 grams. Those are observations from named database records—not a universal range or an estimate of an unseen plate.

Match my meal

Start with the description closest to what you ate

For Grapefruit, begin by separating “Grapefruit, canned” from “Grapefruit, raw.” Choosing a card filters this source set; it does not infer the portion or fill in ingredients the chosen description does not name.

Showing all 2 linked records.

Equal-weight view

How grapefruit records compare at 100 grams

All 2 cited records are shown at the same 100-gram weight. The source servings may differ.

  1. Grapefruit, canned 36 kcal
    36 kcal
  2. Grapefruit, raw 42 kcal
    42 kcal

Shared basis: 100 g · kilocalories

What this page compares

Named source records, not one universal meal

This guide keeps 2 named USDA records in view: 2 direct matches. All sit within “Citrus fruits.” The exact descriptions remain the unit of comparison; the familiar heading is only the doorway into the evidence.

Why these records appear together: The deterministic grouping rule “normalized first description segment” placed these 2 records together under the exact grouping key “grapefruit.” That rule determines membership before any nutrition result is read.

For Grapefruit, this page can compare 2 named records from FDC 2709166 through FDC 2709165. It cannot observe which preparation was eaten, recover unnamed additions, or supply the eaten grams.

Read the shared calculation, provenance, and uncertainty method →

Editor’s decision brief

The three facts to carry into the table

Carry the denominator, exact identity, and strongest observed contrast into every number below.

Portion

125–154 g before composition

The largest source amount is 1.2× the smallest. Read per-serving calorie differences with that mass gap in view.

Composition

6 kcal separates the fixed-weight endpoints

The lower endpoint is “canned”; the higher is “raw.” This isolates density, not ingredient causation.

Discriminator

1.2 g fiber gap per 100 g

Of protein, fiber, and sodium, the strongest normalized contrast is between “canned” (0.4 g) and “raw” (1.6 g).

Observed source examples

Both records, with their own serving weights intact

The cards are ordered by calories in each record's listed serving. Serving weights differ, so use per-100-gram values to compare composition. These selected records do not define a calorie range for every grapefruit.

Important: “Lower” begins with Grapefruit, canned; “higher” ends with Grapefruit, raw, using each record’s own source amount. Those labels order this selected set only—they are not endpoints for every grapefruit meal.

Full comparison

Compare every selected FNDDS record

For Grapefruit, serving columns preserve each record’s own listed amount, while calories per 100 g hold weight constant. A dash means the cited record does not supply that field; it does not mean the nutrient is absent.

On smaller screens, focus the table and scroll horizontally to read every column.

USDA records selected for the Grapefruit nutrition guide
Exact source record Match Source amount Calories kcal / 100 g Protein Fiber Sodium USDA
Grapefruit, canned Direct name match 125 gUSDA reference amount 45 kcal 36 0.7 g 0.5 g 3 mg FDC 2709166 ↗
Grapefruit, raw Direct name match 154 gUSDA reference amount 65 kcal 42 1.2 g 2.5 g 0 mg FDC 2709165 ↗

Portion analysis

Serving total and calorie density answer different questions

The listed source amounts run from 125 to 154 grams—a 29-gram gap before composition enters the comparison. Their own source servings run from 45 calories for “canned” to 65 for “raw.” At a fixed 100 grams, “canned” is 36 calories and “raw” is 42—a fixed-weight separation of 6 calories. For Grapefruit, the serving view answers “how much is in the database portion?”; the 100-gram view answers “how concentrated is the matched record?” Neither reveals how many grams were actually eaten.

The scaling rule: multiply a per-100-gram value by eaten grams ÷ 100. The arithmetic is exact; the result is only as defensible as the record match and portion estimate.

Preparation analysis

The long description carries the evidence

The published descriptions distinguish forms such as “canned” and “raw”. The source formulations contain 2 distinct ingredient codes; examples that appear in only part of the set include grapefruit, raw, pink and red, all areas and grapefruit, sections, canned, water pack, solids and liquids. On this Grapefruit page, those rows make the records inspectable, but they are not a controlled experiment: they cannot tell us that one named input, by itself, caused a nutrient difference.

Database precision is not meal certainty. Retain the exact description beside the number so later corrections remain possible.

What changes the comparison

Four drivers worth checking before choosing a record

The family label “Grapefruit” cannot resolve the differences between Grapefruit, canned and Grapefruit, raw. The four checks below identify the record wording, source weight, and formulation evidence that can.

  1. 01

    Source weight before serving calories

    The source amounts span 125–154 grams. Compare per 100 grams before reading a serving-calorie gap as a composition gap.

  2. 02

    The words that split the family

    Representative record-level distinctions include “canned” and “raw”. Those phrases are evidence for choosing a record, not decorative subtitle text.

  3. 03

    Formulation evidence, with limits

    2 source-input codes appear across the selected records. Their presence and listed weights describe USDA formulations, not finished plated proportions.

  4. 04

    The unresolved plate

    Even “Grapefruit, canned” leaves the eaten grams and unnamed oils, sauces, toppings, substitutions, or leftovers unresolved. Preserve those Grapefruit unknowns for correction instead of converting them into false precision.

Record matching

Match identity first; scale quantity second

Read the source name as a sequence of decisions. First confirm that grapefruit is the right meal family. Then resolve the phrases that actually separate this set—“canned” and “raw”—before comparing gram weight. If a package, menu, or known recipe provides a closer first-party description, prefer it and keep this USDA record as a transparent fallback.

A practical matching checklist

  1. Read the complete Grapefruit source description, including preparation and additions.
  2. Compare the listed source weight with the amount actually eaten.
  3. Prefer a current package or restaurant source when a specific branded item is known.
  4. Record toppings, sauces, cooking fat, sides, and substitutions that the selected description does not name.

Decision support from the exact records on this page

Turn source data into a better next decision

These conclusions and reading paths are computed from 2 exact records behind Grapefruit source-record guide. Links are chosen by record identity, controlled contrast, formulation input, nutrient spread, or serving context—not by loose keyword similarity.

Equal-weight result

Grapefruit, canned is higher in sodium per 100 g

Grapefruit, canned reports 2 mg versus 0 mg for Grapefruit, raw: a 2 mg difference when both are normalized to 100 g.

Inspect the underlying evidence

Check the weight before comparing serving totals

Source amounts span 125–154 g

Grapefruit, canned uses USDA source amount (125 g), while Grapefruit, raw uses USDA source amount (154 g). Use per 100 g for equal-weight composition; use the serving column only when those named source amounts answer your question.

Choose the record before reading the number

Grapefruit, canned and Grapefruit, raw are not interchangeable

The page keeps both records at the same 100 g denominator and makes Preparation wording (No matching controlled term in the source name versus raw) the explicit record-description contrast. It does not show that the wording difference caused a nutrient difference. Pick the description that matches the food in front of you rather than averaging away the distinction.

Inspect the underlying evidence

Contextual knowledge graph

Follow the relationship that matches your question

For Grapefruit source-record guide, each path states why the destination belongs here, so you can distinguish a true evidentiary connection from a merely similar label.

Compare two records on this page Grapefruit, canned vs Grapefruit, raw

Both records appear in this page’s evidence set. The explicit record-description contrast is Preparation wording: No matching controlled term in the source name versus raw; it is a selection cue, not evidence of cause.

Follow this evidence path Put the observed spread in corpus context Sodium: density and serving context

In this page’s records, sodium runs from 0 mg in Grapefruit, raw to 2 mg in Grapefruit, canned, all per 100 g.

Follow this evidence path 2 context records in this source topic Citrus fruits

Grapefruit, canned and Grapefruit, raw belong to this USDA source-category collection. Its displayed ranges and complete exact-record catalog provide the peer set for a manual comparison; the destination does not preselect this page’s record.

Follow this evidence path Put the observed spread in corpus context Dietary fiber: density and serving context

In this page’s records, dietary fiber runs from 0.4 g in Grapefruit, canned to 1.6 g in Grapefruit, raw, all per 100 g.

Follow this evidence path Inspect an exact record Grapefruit, canned

Open the full nutrient table, household measures, formulation inputs, and FoodData Central 2709166 citation for this exact record—not a name-level average.

Follow this evidence path Check another exact record Grapefruit, raw

Open the full nutrient table, household measures, formulation inputs, and FoodData Central 2709165 citation for this exact record—not a name-level average.

Follow this evidence path 2 records share this broad food family Fruit: broader category context

Grapefruit, canned and Grapefruit, raw are assigned to Feast’s Fruit editorial category. Use the category page to compare nearby foods at a broad level; keep the exact USDA descriptions on this page for record-level decisions.

Follow this evidence path