Guides
How to read a food label and what its numbers mean, each rule cited to FDA or USDA and shown on real records from USDA FoodData Central.
Data: USDA FoodData Central, April 30, 2026 release.
How to read a Nutrition Facts label
Read it top to bottom: the serving size first, then calories, then the % Daily Value column, where 5% or less is low and 20% or more is high (FDA).
The % Daily Value, explained
The % Daily Value on a label is how much of a nutrient one serving gives, as a share of a fixed reference amount FDA sets for adults and children 4 and over; 5% or less is low, 20% or more is high.
Net carbs: what they are and how to count them
Net carbs are total carbohydrate minus fiber. FDA has not defined the term, so labels show total carbohydrate; you can work net carbs out from the label yourself.
Calorie density: calories per gram of food
Calorie density is how many calories a gram of food carries. Foods under 1.5 calories a gram (150 per 100 g), mostly vegetables, fruits, soups and cooked grains, let you eat a larger amount for the same calories.
Total sugars and added sugars on the label
Total sugars count every sugar in the food, including those naturally in milk and fruit; added sugars count only the sugars put in during processing, and only added sugars have a Daily Value: 50 g.
Serving sizes: why two labels of the same food differ
A serving size is the amount the label describes, set by FDA's reference amounts for each kind of food since the 2016 rule; within one kind, packages still use different sizes, so compare per 100 g when the servings differ.
What "low sodium", "sugar free" and "high in protein" mean
Words like "low sodium" and "high in protein" are nutrient content claims with fixed FDA meanings, per reference amount; the table gives each one and how many packaged products in USDA's database meet it per labeled serving.
The names sugar goes by in ingredient lists
Sugar goes by dozens of names on ingredient lists. In USDA's branded database, 64% of ingredient statements name at least one sugar and 16% name three or more different ones.
Protein per calorie: foods that give the most
Protein per calorie is grams of protein for every 100 calories: it shows which foods give the most protein for their energy. Lean fish, egg whites, poultry breast and nonfat dairy are near the top, around 20 g per 100 calories.
How to compare two foods fairly
Compare two foods on the same basis: per 100 g to see which is richer or leaner, per serving to see what a portion gives, and against the Daily Value to see what matters. Then look at the whole label, not one number.
Source: FDA, 21 CFR 101.9 (the label, rounding and Daily Values) and 21 CFR 101.12 (serving sizes); USDA FoodData Central, April 30, 2026 release (the examples).