Food Calorie Reference Table

This reference page presents nutrition data across six food categories: Grains & Staples, Fruits, Vegetables, Proteins, Dairy, and Snacks & Beverages. Each table lists serving size, kilocalories, protein in grams, carbohydrates in grams, and total fat in grams per standardized serving. Values are drawn from USDA FoodData Central reference entries for the cooked form where applicable. Use the client-side search input below to filter table rows by food name keyword across all categories simultaneously. Values are reference entries only; actual nutrient composition of physical food items may vary due to cultivar, ripeness, cooking method, added ingredients, and preparation conditions.

Grains & Staples

Fruits

Vegetables

Proteins — Meats, Fish, Eggs, Legumes

Dairy

Snacks & Beverages

USDA Data Methodology and Macronutrient Calorie Density

FoodData Central Data Assembly and Curation Process

USDA FoodData Central is the consolidated public food composition database maintained by the Agricultural Research Service of the United States Department of Agriculture, replacing predecessor databases including the National Nutrient Database for Standard Reference (SR Legacy), the Foundation Foods dataset, and the Food and Nutrient Database for Dietary Studies (FNDDS). Released under a public domain license, FoodData Central aggregates analytical chemistry data from multiple sources. Nutrient values for each food entry may derive from one or more of the following analytical pathways: direct laboratory proximate analysis of representative food samples, brand manufacturer label disclosures imported via the USDA Branded Foods Program, imputation from chemically similar food entries using documented regression algorithms, and literature-derived values curated from peer-reviewed food chemistry journals.

The data curation process within FoodData Central documents which of these pathways produced each nutrient cell, allowing users of the data to distinguish directly measured values from imputed or branded values. For the common food entries listed on this page, most macronutrient entries in the grains, produce, and unprocessed animal product categories originate from direct proximate analysis of multi-location aggregate samples conducted at USDA laboratories or contracted analytical facilities. Branded, packaged, and processed entries may originate from manufacturer label submission via the Branded Foods Program, which requires compliance with FDA nutrient analysis rounding regulations codified in 21 CFR 101.9(c). Values on this page represent single central-reference entries and do not include the standard deviation, sample size, or sampling confidence intervals that are available in the full downloadable FoodData Central JSON and CSV distributions.

Serving Size Definitions and Standardization Conventions

Serving size conventions in USDA reference tables are chosen to correspond with common consumption reporting units used in national dietary survey instruments, primarily the National Health and Nutrition Examination Survey (NHANES) What We Eat in America (WWEIA) dietary recall module. Three serving unit categories appear in the tables on this page. First, volumetric serving units (1 cup, 1 tablespoon, 1 fluid ounce) are calibrated against USDA Food Buying Guide volumetric-to-weight conversion factors for each food in its listed physical form (cooked, raw, chopped, sliced, diced). Second, reference unit servings (1 medium apple, 1 large egg, 1 slice bread) are defined by the FNDDS food coding manual, which specifies gram-weight equivalents for each unit description. Third, the 100-gram reference serving used for entries in the protein category is a standard reference unit in international food composition tables including the FAO/INFOODS system and EuroFIR. Because volumetric-to-weight conversions depend on food density and particle packing, USDA tables document both the serving description and its matching gram weight for each entry, a convention followed in the Serving Size column of the tables above.

FDA Nutrition Facts label serving sizes (Reference Amounts Customarily Consumed, or RACCs) as defined in 21 CFR 101.12(b) overlap with but are not identical to USDA FoodData Central reference servings. For example, the FDA RACC for ready-to-eat cereal is 30 to 55 grams depending on density classification, whereas a 1-cup FoodData Central reference serving of a flaked cereal may fall above or below this range depending on bulk density. Cross-tabulation between the two systems requires consulting the USDA FNDDS Serving Size Crosswalk file.

Atwater Factors: Derivation and Calorie Density Constants

The conventional calorie density multipliers for macronutrients — 4 kcal per gram of protein, 4 kcal per gram of carbohydrate, 9 kcal per gram of fat, and 7 kcal per gram of alcohol — are derived from the experimental work of Wilbur Olin Atwater at Wesleyan University in the 1890s, refined into standard factors adopted by the FAO and codified in USDA Handbook 74. The derivation of each constant proceeds from two experimental stages. First, bomb calorimetry determines the gross heat of combustion of each purified macronutrient sample when fully oxidized in an oxygen atmosphere, yielding upper bounds of approximately 5.65 kcal/g for protein, 4.1 kcal/g for available carbohydrates, 9.45 kcal/g for mixed dietary fats, and 7.1 kcal/g for ethanol. Second, metabolizable energy corrections subtract energy losses in feces, urine, and combustible gases; these correction factors differ by macronutrient class because digestibility and metabolic end-product excretion vary. For protein, approximately 1.6 kcal/g of the gross heat of combustion is lost primarily as urea in urine, reducing the bomb calorimetry figure of 5.65 kcal/g to the convention of 4.0 kcal/g for metabolizable energy.

The carbohydrate Atwater factor of 4 kcal/g applies to available (digestible) carbohydrates, defined as total carbohydrates minus dietary fiber, though the exact handling of fiber depends on the analytical fiber fractionation method used. Dietary fiber carbohydrates are not fully fermented in the human large intestine, and short-chain fatty acid production from fermentable fiber yields a metabolizable energy contribution of 1.5 to 3 kcal per gram depending on fiber type, a range that cannot be captured by a single universal constant. USDA FoodData Central kcal entries may report either Atwater-general calculated values, Atwater-specific values (which use slightly different factors per food category), or direct bomb calorimetry values, and the three approaches produce non-identical totals for the same food entry. The differences are typically within 3% for most common foods but can reach 8–12% for entries high in dietary fiber or resistant starch.

Documented Misconceptions About Food Composition Reference Data

Three categories of misconception appear repeatedly in the public interpretation of USDA food tables. First, reference entries represent population mean values from aggregated food samples; an individual physical specimen of a food item can deviate substantially from the table entry. For example, the USDA central reference value for a medium apple is 95 kcal, but individual apples of different cultivars, harvest locations, and storage durations may range from approximately 80 to 115 kcal depending primarily on moisture and sugar content. Second, cooking method materially affects both serving yield and macronutrient density per serving unit. Raw dry rice at 100 g contains approximately 365 kcal, but the same rice absorbed water during boiling expands to roughly 300 g of cooked rice at 1.22 kcal/g, and entries on this page explicitly reference the cooked form to avoid this source-unit ambiguity. Third, added ingredients during preparation are not included in single-ingredient table entries. A pan-cooked ground beef entry does not account for residual cooking oil retained in the finished product, and a rice entry does not include butter or salt added after cooking unless the table entry explicitly references a prepared recipe.