Start With the Serving Size (The Most Important Line)
Before looking at any other number, find the serving size. This is where labels most commonly mislead consumers. A bag of chips listed as "150 calories" might contain 2.5 servings — meaning the full bag is 375 calories. By law, serving sizes must reflect amounts people "customarily consume," but what the food industry considers customary doesn't always match reality.
Critical trap: A bottle of iced tea or soda often lists 2–2.5 servings, but most people drink the whole bottle. Always multiply all values by the number of servings you'll actually consume.
Daily Value Percentages: A Quick Calibration Tool
The % Daily Value (%DV) column tells you how much a nutrient in one serving contributes to a 2,000-calorie daily diet. The FDA's quick rules:
- 5% DV or less: Low in that nutrient
- 20% DV or more: High in that nutrient
For nutrients you want more of (fiber, vitamins, protein), higher %DV is better. For nutrients to limit (sodium, saturated fat, added sugar), lower %DV is better. At 20%+ DV of sodium in a single serving, that food is contributing meaningfully to your daily limit in just one portion.
The Ingredient List: Ranked by Weight
Ingredients are listed in descending order by weight — the first ingredient is present in the largest amount. This single rule unlocks enormous insight:
- If "sugar" is the first ingredient in a granola bar marketed as "high protein," that's telling
- In "whole grain bread," if whole wheat is the first ingredient, the product is genuinely whole grain — if enriched white flour appears first, "whole grain" is largely marketing
- Multiple forms of the same ingredient (sugar, corn syrup, honey, molasses) spread across the list are a tactic to prevent any single form from appearing too high
Understanding the Macros
Total Fat vs. Saturated vs. Trans
Total fat includes all types. Saturated fat (found in animal products and tropical oils) contributes to cardiovascular risk — current guidance recommends less than 10% of calories from saturated fat. Trans fat (partially hydrogenated oils) is associated with increased cardiovascular risk and is largely banned in the US, though products can list "0g trans fat" if they contain under 0.5g per serving.
Total Carbohydrates, Fiber, and Added Sugar
Total carbohydrates include starches, fiber, and sugars. Dietary fiber (listed separately) should be at least 3g per serving for a "good source" claim. Added sugars (listed separately since 2020) are key: they represent sugar added during processing, separate from naturally occurring sugars in milk or fruit. The 2020 Dietary Guidelines recommend keeping added sugars below 10% of daily calories (~50g for a 2,000-calorie diet).
What "Light," "Reduced," and "Free" Legally Mean
These claims have specific FDA definitions:
- "Light" or "Lite": Must have 1/3 fewer calories OR 50% less fat than the reference food
- "Reduced": At least 25% less of a nutrient than the reference food
- "Free" (as in "fat-free" or "sugar-free"): Less than a specific small amount per serving (e.g., less than 0.5g fat per serving = "fat-free")
- "Good source of": 10–19% DV per serving
- "Excellent source of": 20%+ DV per serving
Sodium: The Overlooked Number
The 2020 Dietary Guidelines recommend no more than 2,300mg of sodium per day — about 1 teaspoon of salt. The average American consumes about 3,400mg/day. Processed foods are the primary source: a single serving of canned soup can contain 800–1,200mg, over half the daily recommended limit. Check sodium %DV on every processed food you buy consistently.