Nutrition

The data

Nutrient values come from the USDA's FoodData Central, Standard Reference Legacy, which lists each food per 100 grams. Every ingredient line is turned into grams, using the weight of a cup, a tablespoon, or one of the thing, and multiplied against the food's values. A line that cannot be turned into grams is not counted, and the breakdown under each label says so.

The rules

The label is laid out the way the FDA lays out a Nutrition Facts panel, with the same nutrients in the same order, the same rounding, and Daily Values figured on a 2,000 calorie day. The breakdown under each label lists every ingredient line, the grams counted, the USDA food used, and any assumption, such as part of a marinade that stays in the pan.

• Calories are the USDA’s calories for each food, added up and divided by the servings. They are rounded to the nearest 10, or to the nearest 5 at 50 calories and under.
• Fat, saturated fat, and trans fat are rounded to the nearest gram, or to the nearest half gram under 5 grams. Carbohydrate, fiber, sugars, and protein are rounded to the nearest gram. Under half a gram prints as 0, and carbohydrate, fiber, sugars, and protein under 1 gram print as “<1g”.
• Sodium is rounded to the nearest 10 milligrams, or to the nearest 5 at 140 milligrams and under. Cholesterol is rounded to the nearest 5 milligrams.
• Each percent Daily Value is figured from the rounded amount on the label. Vitamin D, calcium, iron, and potassium percentages are rounded the way the rule sets out, to the nearest 2 percent up to 10, the nearest 5 up to 50, and the nearest 10 above that. Their amounts are rounded to a tenth for vitamin D and iron and to the nearest 10 milligrams for calcium and potassium.
• Added sugars are all of the sugars in an ingredient that is itself a sweetener or a sweetened sauce, such as brown sugar, maple syrup, honey, and barbecue sauce.
• Meat is counted raw, with all of its fat. Fat that renders out and stays in the smoker or the pan is still on the label, so a label for smoked or grilled meat runs high.
• A range in a recipe is figured at its middle. An ingredient with no amount is figured at the estimate named in the breakdown, or not counted at all.
• A store-bought rub is figured as a home blend of the same kind, listed in the breakdown. A different rub mostly changes the sodium.
• Where the USDA lists no value for a nutrient in a food, that food adds nothing to that line, and the label says so when it could matter.

Sources

• Daily Value on the Nutrition and Supplement Facts Labels, U.S. Food and Drug Administration
• 21 CFR 101.9, Nutrition labeling of food, Legal Information Institute, Cornell Law School
• FoodData Central, U.S. Department of Agriculture

Every recipe, per serving