Label reading
Compare food labels for the amount you actually use
A worked sauce comparison shows why serving size comes before a bigger or smaller number.
Two jars of sauce can look similar on the shelf and use different serving sizes on their labels. Before choosing by the first number you see, decide what you want to compare and how much the recipe needs. This guide uses fictional labels to show the arithmetic. It is a shopping exercise, not a ranking of brands or individualized nutrition advice.
Start with the same amount
FDA explains that nutrient quantities on the Nutrition Facts panel correspond to the stated serving. Serving size describes an amount typically consumed; it is not a recommendation for your portion. Comparing the numbers is useful only when you also compare their bases.
Imagine Sauce A lists 300 mg sodium for ½ cup, while Sauce B lists 180 mg for ¼ cup. The smaller printed number belongs to B, but that serving is half as large. For ½ cup, double B’s value: 180 × 2 = 360 mg. At equal volumes, A has less sodium in this fictional example. That conclusion concerns sodium alone; it is not an overall verdict on either sauce.
Carry the comparison into the recipe
Suppose your recipe uses 2 cups of sauce for four portions. Sauce A contributes 1,200 mg sodium to the whole dish from the sauce, or 300 mg per portion if evenly divided. Sauce B contributes 1,440 mg to the dish, or 360 mg per portion. Cheese, pasta, seasoning and other ingredients are outside that calculation.
Write the calculation as three small steps: amount needed divided by label serving size, multiplied by the nutrient amount, then divided by recipe portions. Avoid calling the result a complete nutrition analysis. It estimates one ingredient’s contribution from rounded label values and assumes the dish is divided equally. The actual portion you serve may differ.
Read the sugar lines without adding them twice
FDA distinguishes total sugars from added sugars: added sugars are included within the total. If a fictional label lists 8 g total sugars including 3 g added sugars, the total remains 8 g, not 11 g. Keep those lines separate when comparing products.
Choose the comparison that answers your shopping question. For a sauce, you might compare sodium at equal amounts. For a sweetened yogurt, you might compare added sugars at equal amounts. Keep the ingredient list, taste preferences and recipe requirements in view too. A number by itself cannot tell you whether a thin sauce will work in a casserole designed around a thick one.
Make a useful shelf-side note
A quick note can contain the ingredient, the volume needed, the nutrient you are comparing and the equal-portion values. For our example: “Sauce, 2 cups; sodium per ½ cup: A 300 mg, B 360 mg.” That is enough to avoid redoing the same calculation when you return to the aisle.
Use the actual packaging each time you shop; recipes and formulations can change. Do not copy these invented numbers into a nutrition tracker as though they describe a real product. If you follow a medically prescribed eating plan, use the targets and advice provided by your qualified clinician. For ordinary shopping, the habit to keep is simpler: compare the same amount, then account for the amount your recipe uses.
| Comparison | Sauce A | Sauce B |
|---|---|---|
| Label serving | ½ cup | ¼ cup |
| Sodium per label serving | 300 mg | 180 mg |
| Sodium per ½ cup | 300 mg | 360 mg |
| Sodium in 2 cups | 1,200 mg | 1,440 mg |
| Sauce contribution per ¼ of dish | 300 mg | 360 mg |
Read the source
Sources checked 2026-10-09.
Put it into practice ↗