Sources and limits
The food data
Every amount comes from the USDA FoodData Central SR Legacy release (April 2018), the final edition of the USDA National Nutrient Database for Standard Reference. Values are per 100 grams of the edible portion, for the food in the state its description names — "Bananas, raw", "Chicken, broilers or fryers, breast, meat only, cooked, roasted". Each food's table on this site keeps that description and its FDC number.
Suggested citation: U.S. Department of Agriculture, Agricultural Research Service. FoodData Central. fdc.nal.usda.gov.
Licence
USDA states that FoodData Central data "are in the public domain and they are not copyrighted. They are published under CC0 1.0 Universal (CC0 1.0)", and asks that FoodData Central be listed as the source (FDC API guide, Licensing). Food vs reorganises the figures and does not represent or speak for USDA.
Daily Values
Percentages use the FDA Daily Values for adults and children aged 4 and over — the reference amounts printed on US Nutrition Facts labels, built around a 2,000-calorie diet. They are a yardstick for reading labels. Children, pregnancy, age, size, activity and health conditions all change what a person needs.
| Nutrient | FDC id | Daily Value | Foods without data |
|---|---|---|---|
| Calories | 1008 | 2,000 kcal | 0 |
| Protein | 1003 | 50 g | 0 |
| Fat | 1004 | 78 g | 0 |
| Saturated fat | 1258 | 20 g | 6 |
| Carbohydrate | 1005 | 275 g | 0 |
| Fiber | 1079 | 28 g | 11 |
| Sugars | 2000 | none (FDA sets one for added sugars only) | 44 |
| Cholesterol | 1253 | 300 mg | 9 |
| Sodium | 1093 | 2,300 mg | 0 |
| Potassium | 1092 | 4,700 mg | 1 |
| Calcium | 1087 | 1,300 mg | 0 |
| Iron | 1089 | 18 mg | 0 |
| Magnesium | 1090 | 420 mg | 2 |
| Vitamin A | 1106 | 900 µg | 14 |
| Vitamin C | 1162 | 90 mg | 9 |
How the 486 foods were chosen
From SR Legacy's 7,793 entries, common foods were picked by hand: raw produce, simply cooked meat, fish, grains and legumes, plain dairy, nuts, oils and a few staples. Branded, restaurant, baby and mixed-dish entries were left out, and near-duplicates (the same cut at several trims, or the same food with and without salt) were reduced to one. Names were rewritten the way people say them, with the cooking state kept in the name.
Servings
USDA records household measures for most foods — "1 medium (7 to 7-7/8 inches long)", "1 cup, chopped". For each group one kind of measure is preferred (a medium fruit, a cup of vegetables or cooked grains, an ounce of nuts or cheese, a tablespoon of oil). Meat and fish use 3 ounces; where USDA lists only 1 ounce, that weight is multiplied by three. 4 foods have no household measure and stay at 100 g. Where USDA gives only an NLEA serving — the reference amount used on US labels — it is shown as “label serving (NLEA)”; the other servings are household measures, not label reference amounts.
Missing values
When USDA gives no figure, the site shows "no data" and leaves that nutrient out of the comparison and the rankings. It never fills a gap with zero. Gaps here: saturated fat 6, fiber 11, sugars 44, cholesterol 9, potassium 1, magnesium 2, vitamin a 14, vitamin c 9.
Checked against the source
Thirty-six values for six foods (banana, avocado, roasted chicken breast, almonds, cooked farmed Atlantic salmon and raw sweet corn) were compared with the FoodData Central API for the same FDC numbers; all matched. Amounts are kept to two decimals so small values such as iron are not rounded away.
Cooking yields (raw to cooked)
The raw-to-cooked converter uses only weights printed in the same SR Legacy table: a cooked entry's portion that names the raw weight it came from (“1 patty (yield from 1/4 lb raw meat)”), the poultry entries that give raw and cooked meat from “1 lb ready-to-cook chicken”, the raw ground-turkey note “1 patty (cooked from 4 oz raw)”, and couscous's “1 cup, dry, yields 528 g” against the dry cup weight. No average or rule-of-thumb yield is used. A cooked entry is left out when USDA's raw and cooked protein for the same piece differ by more than 10%, because then the two entries cannot be the same food; that removed fried chicken meat, 97% lean ground beef, 85% lean ground turkey and ground veal. Rice, pasta, lentils, beans and quinoa have no such weights in SR Legacy and are not converted.
What the numbers cannot tell you
SR Legacy figures are averages from samples analysed years ago; a particular apple, a different variety or a different cooking time will differ. Total sugars include both natural and added sugar. Vitamin A is given as retinol activity equivalents. The site compares amounts and says nothing about which food is healthier — see about.