How to Read a Nutrition Label
A working guide to the FDA's Nutrition Facts panel, written for people who already know how to count calories and want to understand what they're actually looking at. We cover what every line means, how the FDA sets serving sizes, the difference between added and total sugar, the "high in protein" threshold, ingredient order rules, and the common ways labels can mislead even when they're technically accurate.
The short answer
A US nutrition label is a regulated document. The FDA sets the format, the rules for what counts as a serving, the thresholds for nutrient claims like "high in protein," and the order in which ingredients must be listed. None of these are voluntary; manufacturers cannot freely choose serving sizes to flatter their numbers. But the rules also have well-known gaps — small serving sizes can hide high per-gram values; "low fat" labels are unregulated for many specific foods; the difference between "naturally-occurring" and "added" sugar isn't always meaningful biologically. This guide walks through what's actually on the label and what to watch for.
The Nutrition Facts panel, line by line
1. Serving size and servings per container
The first two lines on every Nutrition Facts panel are Serving Size and Servings Per Container. These are not suggestions — they're the basis for every other number on the label. Every calorie, gram, and milligram listed below applies to one serving, not to the whole package.
The FDA controls serving size via the Reference Amount Customarily Consumed (RACC) for each food category — the median amount Americans actually eat in one sitting, based on national consumption surveys. A few examples:
- Greek yogurt: 170 g (about 6 oz)
- Cottage cheese: 110 g
- Ready-to-eat cereal: 30 g (varies slightly by density)
- Protein bars: 40 g
- Beef jerky: 28 g (1 oz)
- Carbonated beverages: 240 mL (8 fl oz)
For packages containing less than 200% of the RACC, the entire package is treated as one serving. For packages containing 200% or more, the label must show both "per serving" and "per package" values for at least calories and select nutrients. This is why a 20 oz bottle of soda lists 2.5 servings — the FDA forces the disclosure because the package is more than twice the standard.
Where this gets tricky: very small serving sizes — pretzels at 28 g, cookies at 30 g — can make calorie and sodium numbers look modest per serving but actually be quite high per 100 g or per typical-consumption portion. We always cross-reference per-100 g at Labelgrade for exactly this reason.
2. Calories
Listed prominently and in larger type since the FDA's 2016 label update. Calories come from four macronutrients:
- Protein: 4 calories per gram
- Carbohydrates: 4 calories per gram
- Fat: 9 calories per gram
- Alcohol: 7 calories per gram
Fiber, while a carbohydrate, contributes 0-2 calories per gram depending on type (soluble fiber is partially fermented in the gut; insoluble fiber passes through). The label simplifies by counting all fiber as part of total carbohydrate. The per-calorie math on labels can be slightly off because of fiber and water content rounding, but it's typically within 5%.
3. Total fat, saturated fat, trans fat
Total fat is the sum of all fat (saturated, unsaturated, trans). Saturated fat and trans fat are broken out because the FDA recommends limiting both — saturated to under 20 g/day and trans to "as low as possible" (the FDA partially banned partially hydrogenated oils starting in 2018, eliminating most trans fat from the US food supply).
The FDA Daily Value for total fat is 78 g (based on a 2000-calorie diet). 20% DV per serving (15.6 g) qualifies as "high"; 5% DV or less (3.9 g) qualifies as "low."
Trans fat watch: labels can list "0 g trans fat" if the actual content is less than 0.5 g per serving. Multiple servings of a product with 0.4 g per serving can add up. The "0 g trans fat" claim is meaningful but not absolute — check the ingredient list for "partially hydrogenated oil" if you're strictly avoiding trans fats.
4. Cholesterol
Listed in milligrams. The FDA Daily Value reference is 300 mg, but the 2015 Dietary Guidelines removed the specific upper limit because research shows dietary cholesterol has less impact on blood cholesterol than previously thought (saturated fat is a bigger driver). Still listed on every label for backwards compatibility and because some people track it.
5. Sodium
Listed in milligrams. FDA Daily Value: 2300 mg (about 1 teaspoon of salt). Thresholds:
- Low sodium: 140 mg or less per serving (5% DV)
- Very low sodium: 35 mg or less per serving
- Sodium-free: less than 5 mg per serving
- "No salt added" — no salt added during processing; naturally-occurring sodium remains
- "Reduced sodium" — at least 25% less than the reference product
Sodium is the most consistent place where small serving sizes hide significant load. Beef jerky at 540 mg per ounce looks like 23% DV per serving; per 100 g it's nearly 1900 mg, or 82% of the daily limit. We grade sodium on a per-100 g basis at Labelgrade.
6. Total carbohydrate, dietary fiber, total sugars, added sugars
Total carbohydrate includes fiber, sugars, and starches.
Dietary fiber: the FDA Daily Value is 28 g; 20% (5.6 g) per serving qualifies as "high"; 10% (2.8 g) as "good source."
Total sugars: all sugars, including naturally-occurring (lactose in milk, fructose in fruit, glucose in dates) and added.
Added sugars: only sugars added during processing or preparation (cane sugar, honey, syrups, fruit juice concentrate). Required on labels since 2020. The FDA Daily Value is 50 g (10% of a 2000-calorie diet), but the American Heart Association recommends much less — 25 g for adult women, 36 g for adult men.
Why the distinction matters: 10 g of sugar in plain Greek yogurt (lactose) is biochemically different from 10 g of added cane sugar. Lactose is bound to the milk protein matrix and absorbed more slowly; cane sugar in a soft drink reaches the bloodstream within minutes. The per-gram blood-sugar impact is not the same. The added-sugar line is what to watch for FDA targets; the total-sugar line is what to watch for blood-sugar management.
7. Protein
Listed in grams. FDA Daily Value: 50 g. Thresholds:
- "High in protein" or "Excellent source": 20% DV per serving = 10 g
- "Good source of protein": 10% DV per serving = 5 g
To carry a "high in protein" claim, the food must also meet the FDA's protein quality criteria (Protein Digestibility-Corrected Amino Acid Score, or PDCAAS, of at least 0.5). Most animal proteins easily meet this; some isolated plant proteins (especially gluten/wheat protein) do not.
%DV for protein is technically optional on most labels. The protein gram amount is required, but the percentage can be omitted unless the label makes a protein claim. This is why many high-protein products voluntarily include the %DV — it strengthens the marketing.
8. Vitamins and minerals
The FDA requires four to be listed: vitamin D, calcium, iron, and potassium. Other vitamins and minerals are optional unless the food is fortified with them or makes a claim about them. Each is listed in actual units (mcg, mg) and %DV.
Ingredient lists: the rules
Ingredients are listed in descending order by weight. The first ingredient is the largest by weight; the last is the smallest. This rule applies to every ingredient above the 2% threshold. Once an ingredient is below 2% of total weight, it can be listed in any order, typically after the phrase "contains less than 2% of the following:" or similar.
What "first ingredient" actually means: a yogurt listing "cultured milk" first means milk is the largest single ingredient by weight. It does not mean the product is mostly milk in any other sense. A product listing "whole grain wheat flour" first might still be only 35% whole grain wheat flour by weight if the other ingredients are spread out enough.
The "natural flavors" loophole: "natural flavors" can include hundreds of distinct chemical compounds (plant extracts, essential oils, fermentation products, etc.) without breaking them out. The FDA defines "natural" loosely: derived from a plant, animal, or microbial source rather than synthesized. This is why an ingredient list can be technically short but functionally complex.
Sub-listed ingredients: a compound ingredient (like "chocolate chips" or "vitamin and mineral blend") must have its own sub-ingredients listed in parentheses or in a separate sub-list. This is where the ingredient count balloons on engineered foods like protein shakes.
Common label claims and what they require
| Claim | FDA requirement |
|---|---|
| "High in protein" / "Excellent source" | ≥ 20% DV per serving (10 g) + protein quality threshold |
| "Good source of protein" | ≥ 10% DV per serving (5 g) |
| "Low fat" | ≤ 3 g fat per serving |
| "Fat-free" | < 0.5 g fat per serving |
| "Low sodium" | ≤ 140 mg per serving |
| "Low sugar" | ≤ 5 g per serving |
| "No added sugar" | No sugars added during processing; naturally-occurring sugars remain |
| "Sugar-free" | < 0.5 g per serving (sugar alcohols allowed) |
| "Reduced [nutrient]" | ≥ 25% less than the reference product |
| "Light" / "Lite" | 33% fewer calories OR 50% less fat than reference, with required disclosure |
| "Natural" | Not regulated for most foods — minimally processed, no artificial ingredients (advisory only) |
| "Healthy" | Specific criteria per category — limits on saturated fat, sodium, added sugar; food group requirements (updated 2024) |
Where labels can mislead even when they're accurate
Small serving sizes hide high per-gram numbers. Beef jerky, cooking oils, salad dressings, and cured meats all use serving sizes around 1-2 tablespoons or 1 oz. These look modest per serving but are dramatically dense per 100 g.
"Per serving" math obscures what one bottle/bag contains. A 20 oz soda lists 2.5 servings — if you drink the bottle, you've consumed 2.5× the listed sugar and calories.
"Made with whole grains" doesn't mean primarily whole grains. A label can claim this if any whole grain is present. The first-ingredient-by-weight test catches this — if the first ingredient is enriched white flour and whole wheat flour is third, the product is mostly refined.
"No high-fructose corn syrup" doesn't mean no added sugar. Cane sugar, brown rice syrup, tapioca syrup, and honey are all added sugars; HFCS is just one specific form.
"Gluten-free" doesn't mean low-carb or healthy. A gluten-free cookie made with rice flour, sugar, and palm oil has the same nutritional profile as a regular cookie, often with less protein.
%DV is calculated against a 2000-calorie reference diet. If you eat 1500 or 2500 calories per day, your personal DVs shift proportionally. A 20% DV per serving is "high" for someone eating 2000 calories; for someone eating 2500, it's 16%.
How Labelgrade reads a label
We use the FDA Nutrition Facts panel as the source of truth, cross-referenced against USDA's Branded Foods database for verification. The Labelgrade dimensions translate the label into a clearer signal:
- Protein density — grams of protein per 100 g of product, capped at the equivalent of plain cooked chicken breast (31 g per 100 g)
- Ingredient quality — count of ingredients, presence of artificial sweeteners, sugar alcohols, phosphate additives, and isolate-based proteins; bonuses for whole-food first ingredients
- Sugar load — sugars per 100 g, with adjustments for whole-food sources (dates, dairy lactose) vs added sugars
- Sodium load — sodium per 100 g, on a scale that ignores small-serving-size camouflage
- Fiber — fiber per 100 g, weighted lighter for animal products where zero fiber is expected
The full methodology is at /methodology. The point is to apply the same lens consistently across products, so a 6 g-protein clean snack and a 12 g-protein additive-laden bar can be compared on something other than "more protein = better."
Frequently Asked Questions
What does "Daily Value" (%DV) mean on a nutrition label?
Daily Value is the FDA-set reference amount of a nutrient that a person should consume (or stay under) in a day, based on a 2000-calorie reference diet. The percentage tells you what fraction of that daily target one serving provides. A %DV of 5% or lower is considered low; 20% or higher is considered high. The reference targets: 50 g protein, 78 g total fat, 275 g total carbohydrate, 28 g dietary fiber, 50 g added sugar (limit), 2300 mg sodium (limit), 300 mg cholesterol (limit).
How is serving size determined?
The FDA publishes a Reference Amount Customarily Consumed (RACC) for each food category. Manufacturers cannot freely choose a small serving size to make their numbers look better — the serving on the label must reflect what a typical person actually eats in one sitting. For example, ice cream has a RACC of 2/3 cup (about 87 g) and Greek yogurt is 170 g. If a package contains less than 200% of the RACC, the label must show "per package" values; if it contains 200% or more, it must show both "per serving" and "per package."
What's the difference between "added sugar" and "total sugar"?
Total sugars include all sugars in the food — both naturally-occurring (lactose in milk, fructose in fruit) and added (cane sugar, honey, corn syrup, fruit juice concentrate). Added sugars are only those added during processing or preparation. Since 2020, the FDA requires the Nutrition Facts label to break these out separately. The added-sugar line is what to watch for FDA targets: the Daily Value is 50 g, but the American Heart Association recommends much less (25 g for women, 36 g for men).
How does the FDA define "high in protein"?
A food can be labeled "high in protein" or "excellent source of protein" if it contains 20% or more of the Daily Value per serving (10 g, since the DV is 50 g). For "good source of protein," the threshold is 10% (5 g). These are also based on the FDA's "high-quality protein" criteria — adjustments for protein quality (the Protein Digestibility-Corrected Amino Acid Score, or PDCAAS) can affect what protein "counts" toward these claims. Animal proteins generally meet the criteria; isolated plant proteins sometimes do not.
Why are ingredients listed in a specific order?
FDA regulation requires ingredients to be listed in descending order by weight. The first ingredient is what there's most of by weight; the last is what there's least of. Ingredients listed at "less than 2% of the following:" are below the 2% threshold and not required to be ordered by weight among themselves. This is why a product called "honey-sweetened" might list a different sweetener first — honey was added later in smaller quantity.
What's the "high in protein" claim worth?
It's a useful filter when you're looking at packaged foods, but it's not a quality metric. A bar with 12 g of protein from soy isolate, sugar, and palm kernel oil meets the same threshold as a bar with 12 g of protein from egg whites and almonds. The Labelgrade methodology layers ingredient quality on top of the FDA threshold, which is why a clean 6 g-protein product can grade higher than a 12 g-protein product full of additives.
How do I read sodium content on a label?
Sodium is listed in milligrams (mg) per serving. The FDA Daily Value is 2300 mg (about 1 teaspoon of salt). A food with 5% DV or less per serving (115 mg) is considered low-sodium; 20% DV or more (460 mg) is high. Note: sodium content is a *per-serving* number — if you eat twice the serving size, you double the sodium. We grade sodium on a *per-100 g* basis at Labelgrade because that catches small-serving foods like jerky that look low per ounce but are dramatically high per gram.
What does "% Daily Value" mean for vitamins and minerals?
Same idea as for protein or sodium: the percentage shows what fraction of one day's recommended intake the serving provides. The FDA updates these reference values periodically. Foods can claim "high in [nutrient]" or "excellent source of [nutrient]" at the 20% DV threshold, and "good source" at 10%. For vitamins, "%DV" reflects food composition rather than absorption — a high-iron number on a plant-based food doesn't mean your body will absorb iron at the same rate as it would from heme-iron in meat.
How accurate is the FDA serving size for a typical person?
The FDA RACC values are based on consumption survey data from the early 1990s, updated in 2016. They reflect the median serving size at the time of the survey. For some categories — protein bars, granola, single-serve ice cream pints — typical consumption has shifted since the survey, and the RACC may not match what people actually eat. This is why we always emphasize comparing products on a per-100 g basis in addition to per-serving.