Food Calorie Reference Table 2025: USDA FoodData Central Macro Nutrient Values

Food composition reference tables are among the oldest continuously maintained datasets in public nutrition research. Every dietary recall methodology, every nutrition label calculation standard, and every epidemiological survey of population intake rests, ultimately, on a food composition database that assigns energy and macronutrient values to specific edible food items. In the United States, the authoritative public repository for this information as of 2025 is USDA FoodData Central, a unified platform maintained by the Agricultural Research Service that consolidates the earlier Standard Reference (SR) series, the Food and Nutrient Database for Dietary Studies (FNDDS), and the curated Foundation Foods dataset. This page documents the structure of USDA FoodData Central and the three Atwater 4-4-9 macronutrient energy conversion factors that underlie metabolizable energy calculations, presents a per-100-gram reference table for 30+ commonly consumed staple foods across all major food groups, works through a complete Atwater-factor calculation for a hypothetical sample, and explains the documented sources of minor variance between simplified three-factor estimates and the official USDA-listed kilocalorie figures.

Readers who wish to look up additional foods beyond those in the printed reference table on this page can use the [Food Calorie Table + ../tools/food-calorie-table.html] which implements a searchable per-100g and per-serving lookup interface populated with USDA FoodData Central reference values. Combined with the Exercise Calorie Burn Calculator and TDEE Calculator linked elsewhere on this site, the food calorie lookup completes the two sides of the standard energy balance identity — intake and expenditure — required as inputs to calorie deficit calculation workflows.

USDA FoodData Central as Primary Public Data Source

USDA FoodData Central is maintained by the Agricultural Research Service (ARS) of the United States Department of Agriculture. It was launched in April 2019 as a unified successor platform to several previously separate USDA food composition databases: the Standard Reference (SR) series most recently SR28, the Food and Nutrient Database for Dietary Studies (FNDDS) updated biennially in parallel with each What We Eat in America (WWEIA) National Health and Nutrition Examination Survey dietary recall cycle, and the USDA Branded Food Products Database. FoodData Central consolidates these historical databases under a single data model and application programming interface (API) while preserving provenance metadata identifying the source component for each food entry.

FNDDS (Food and Nutrient Database for Dietary Studies) is the survey-oriented component. Each FNDDS release is timed to correspond to the dietary recall data collected in a two-year WWEIA/NHANES survey cycle, enabling researchers to convert reported food intake recalls into nutrient intake estimates using composition values aligned with the foods actually available to respondents at the time of survey fieldwork. The most recent public release at time of writing is FNDDS 2023-2024, which corresponds to the 2023-2024 NHANES cycle. FNDDS includes both disaggregated raw ingredient entries and aggregated mixed-dish entries representing the multi-component foods most commonly reported in dietary recalls (for example, a commercially prepared pizza or a restaurant sandwich rather than only flour, cheese, and tomato sauce separately).

SR Legacy (Standard Reference Legacy) is the historical compiled nutrient table component, tracing its lineage back through USDA Handbook 8 and earlier twentieth-century USDA food composition publications. SR Legacy contains nutrient composition data for a broad catalog of raw agricultural commodities, minimally processed foods, and intermediate culinary ingredients. Foundation Foods is the research-grade curated component, where analytical data entries are directly linked to specific food samples including cultivar, agricultural production origin, harvest date details, and analytical method metadata in cases where the underlying laboratory work is documented. For common staple foods represented in all three components, the energy and macronutrient values typically agree within a few percent, with minor variation reflecting the different intended analytical depths of each database component.

Atwater 4-4-9 Macronutrient Factors

The Atwater 4-4-9 macronutrient energy conversion system is the standard convention used to compute estimated metabolizable food energy from measured macronutrient composition. The system assigns three reference factors, each expressed in kilocalories per gram of macronutrient, to the three classes of energy-yielding macronutrients in human nutrition.

Protein Factor: 4 kcal per gram

Protein, measured as total nitrogen multiplied by the Jones factor of 6.25 (or food-specific nitrogen-to-protein conversion factors for specific food matrices in refined systems), is assigned an average metabolizable energy value of 4 kilocalories per gram. This factor accounts for the metabolizable energy of amino acid carbon skeletons after correction for the energy content of urea and other nitrogenous waste products excreted in urine. The 4 kcal/g protein factor is a population average; individual amino acids vary slightly in their heats of combustion and metabolic fate.

Carbohydrate Factor: 4 kcal per gram

Available carbohydrate, defined as total carbohydrate minus indigestible dietary fiber in the modified Atwater system, is assigned an average metabolizable energy value of 4 kilocalories per gram. In simplified implementations of the system that do not separate fiber from total carbohydrate, the 4 kcal/g factor is applied to the entire carbohydrate class. The digestible monosaccharides, disaccharides, and digestible polysaccharides (starches) that constitute the metabolizable carbohydrate fraction all yield approximately 4 kcal/g when oxidized to carbon dioxide and water via glycolysis, the citric acid cycle, and oxidative phosphorylation.

Fat Factor: 9 kcal per gram

Total lipid (fat), measured as the sum of triglycerides, phospholipids, sterols, and other ether-extractable compounds depending on the specific analytical method (typically Soxhlet extraction or acid hydrolysis), is assigned an average metabolizable energy value of 9 kilocalories per gram. The high energy density of the fat class reflects the high degree of reduction of carbon-carbon bonds in fatty acid acyl chains relative to the more oxidized carbon skeleton of carbohydrates and the nitrogen-containing side chains of amino acids. Triglycerides, which constitute the vast majority of edible fat mass, account for the 9 kcal/g reference value; minor lipid classes such as phytosterols contribute negligibly to net metabolizable energy at typical dietary concentrations.

The historical origin of the 4-4-9 factor system is the 1900 publication of USDA Office of Experiment Stations Bulletin 28 by Wilbur Olin Atwater and Charles D. Bryant, titled "The Chemical Composition of American Food Materials." Atwater's laboratory conducted systematic bomb calorimetry measurements of gross heat of combustion for purified macronutrient fractions and food materials, combined with respiration and balance studies to measure the fraction of gross energy actually retained metabolically after urinary and fecal losses. The resulting 4-4-9 reference values have remained in continuous use for over 125 years, with refinements (modified Atwater factors, fiber correction terms) added in subsequent decades but the original three-factor core structure preserved across all national and international food labeling standards and dietary survey methodologies.

Full Reference Table 30+ Food Rows (kcal/100g, Protein g, Fat g, Carbs g, Fiber g)

The reference table below presents approximate energy and macronutrient values per 100 grams of edible portion for 30+ commonly consumed foods. Values are compiled from USDA FoodData Central public entries drawn from FNDDS 2023-2024, SR Legacy, and Foundation Foods datasets. Row ordering groups foods by broad category: grains and starches, legumes and pulses, animal proteins (meat, poultry, fish, eggs, dairy), fruits and vegetables, nuts and seeds, added fats and oils. All values are approximate population reference figures; specific cultivar, agricultural growing conditions, and preparation method (raw, boiled, baked, fried) introduce measurable variance. Readers requiring exact FoodData Central Central Data ID (FDC ID) linked values with analytical method metadata should consult the primary USDA database directly via the links in the source citations section.

Food Name (Preparation)	kcal per 100g	Protein (g)	Total Fat (g)	Carbs (g)	Fiber (g)
Rice, white, long-grain, cooked (boiled)	130	2.7	0.3	28.1	0.4
Pasta, spaghetti, enriched, cooked (boiled)	158	5.8	0.9	31.0	1.8
Bread, whole-wheat, commercially prepared	247	13.0	3.4	41.0	7.0
Oats, rolled, regular, raw (dry)	389	16.9	6.9	66.3	10.6
Potato, Russet, baked with skin	93	2.6	0.1	21.2	2.2
Lentils, mature seeds, cooked, boiled	116	9.0	0.4	20.1	7.9
Chickpeas (garbanzo), cooked, boiled	164	8.9	2.6	27.4	7.6
Black beans, cooked, boiled	132	8.9	0.5	23.7	8.7
Chicken, breast, boneless, skinless, raw	165	31.0	3.6	0.0	0.0
Beef, eye of round, lean only, raw	250	26.5	15.0	0.0	0.0
Salmon, Atlantic, farmed, raw fillet	208	20.4	13.4	0.0	0.0
Tuna, light, canned in water, drained	116	25.5	0.8	0.0	0.0
Egg, whole, large, raw, shell removed	155	13.0	11.0	1.1	0.0
Milk, reduced-fat, 2% milkfat, fluid	50	3.4	2.0	4.8	0.0
Yogurt, Greek, plain, nonfat	59	10.2	0.4	3.6	0.0
Cheese, cheddar, block, natural	402	25.0	33.1	1.3	0.0
Tofu, firm, prepared with calcium sulfate	76	8.0	4.8	1.9	0.3
Apple, raw, with skin, Red Delicious	52	0.3	0.2	13.8	2.4
Banana, raw, Cavendish, peeled	89	1.1	0.3	22.8	2.6
Orange, raw, Navel, peeled sections	47	0.9	0.1	11.8	2.4
Avocado, raw, Hass, all varieties	160	2.0	14.7	8.5	6.7
Strawberries, raw	32	0.7	0.3	7.7	2.0
Broccoli, raw, florets and stems	34	2.8	0.4	6.6	2.6
Spinach, raw, leaves	23	2.9	0.4	3.6	2.2
Carrots, raw	41	0.9	0.2	9.6	2.8
Almonds, raw, whole, blanched	579	21.2	50.6	21.6	12.5
Walnuts, English, raw, halved	654	15.2	65.2	13.7	6.7
Peanut butter, smooth style, with salt	588	25.1	50.4	20.0	6.0
Olive oil, extra virgin, salad/cooking	884	0.0	100.0	0.0	0.0
Butter, salted, stick, cream	717	0.9	81.1	0.1	0.0
Honey, extracted, raw/commercial	304	0.3	0.0	82.4	0.2

How to Read and Interpret the Reference Table

Each row of the reference table corresponds to one food item. The first column identifies the food by common name and, where relevant, specifies the preparation method (raw, cooked, boiled, baked, canned, dried) because preparation method is a primary determinant of per-100g nutrient values due to moisture loss during cooking. Cooking and thermal processing concentrate dry mass per unit of final weight; for example, dry raw rolled oats at 389 kcal/100g become approximately 70–75 kcal/100g when prepared as cooked oatmeal because the final hydrated mass is roughly five-sixths water by weight. Always verify that the preparation context of a table row matches the food actually being consumed before applying the per-100g values to a specific intake record.

The five numeric columns in each row are: kilocalories per 100g edible portion; protein in grams per 100g; total fat in grams per 100g; total carbohydrate in grams per 100g; and total dietary fiber in grams per 100g. Note that dietary fiber grams are a sub-component of total carbohydrate grams; the four macronutrient columns do not sum to 100g because the remaining mass per 100g edible portion consists of water, mineral ash, and (in some foods) non-nutritive organic minor constituents. For a dehydrated food such as olive oil or butter, the fat column accounts for nearly 100% of the edible mass; for a high-moisture food such as raw spinach or reduced-fat milk, the sum of the four macronutrient columns is well under 20% of total 100g mass, with water accounting for the vast majority of the remainder.

Atwater Factor Worked Calculation Example: Sample 20g Protein, 10g Fat, 30g Carb per 100g

This worked example demonstrates full step-by-step application of the simplified three-factor Atwater 4-4-9 system to a hypothetical 100-gram food sample with known macronutrient composition, then compares the three-factor estimate against a typical USDA-listed value and explains the documented sources of minor numerical variance. Sample inputs per 100g: Protein = 20 g, Total fat = 10 g, Total carbohydrate = 30 g. The sample food also contains 4 g of dietary fiber within the total carbohydrate fraction.

Step 1: Write the Three-Factor Atwater Formula

Estimated kcal/100g = (Protein_g × 4 kcal/g) + (Fat_g × 9 kcal/g) + (Carbohydrate_g × 4 kcal/g)

Step 2: Substitute Macronutrient Values and Compute Each Term

Protein contribution = 20 g × 4 kcal/g = 80 kcal.

Fat contribution = 10 g × 9 kcal/g = 90 kcal.

Carbohydrate contribution = 30 g × 4 kcal/g = 120 kcal.

Step 3: Sum the Three Products

Total Atwater estimated kcal = 80 + 90 + 120 = 290 kcal per 100g.

Step 4: Compare to a Hypothetical USDA FoodData Central Listed Value and Explain Variance

Suppose the same hypothetical food's official USDA FoodData Central listed energy value is 282 kcal per 100g rather than the 290 kcal computed by the simplified three-factor sum. The 8 kcal difference is well within the documented variance range for foods containing significant fiber and mineral ash. Three principal contributors account for the discrepancy. First, the 4 g of dietary fiber within the total carbohydrate fraction yields fewer metabolizable kilocalories per gram than the 4 kcal/g digestible carbohydrate factor; subtracting the fiber and applying a reduced factor to the residual digestible carbohydrate fraction would lower the estimate. Second, mineral ash (inorganic salt fraction) and non-metabolizable organic minor constituents contribute zero kilocalories but occupy a portion of the 100g denominator that the three-factor system implicitly treats as if it contributed energy proportionally. Third, USDA bomb-calorimetry-derived values incorporate metabolizable energy corrections for urinary nitrogen losses (for protein) and specific fatty acid profiles (for fat) that differ marginally from the rounded class-average 4-4-9 reference factors. The direction and magnitude of these differences vary by food class; for high-fiber foods such as whole grains, legumes, and vegetables the three-factor uncorrected sum typically overestimates the listed USDA value by 1–6% depending on fiber content, while for refined low-fiber high-fat foods such as pure oils the three-factor sum matches the USDA listed value almost exactly because the oil is essentially 100% triglyceride with no ash or fiber to introduce correction terms.

Data Source Citations