THE TAKEAWAY

Read the serving size first. Calories and nutrient amounts usually refer to that serving, so scale them to the amount you actually eat.

Read the top of the label first

On a US Nutrition Facts label, find “servings per container” and “serving size” before looking at calories. A label can describe one serving even when the package holds several. Some products display separate columns for a serving and the whole package.

The FDA explains that serving size is based on typical consumption, not a recommendation. Treat it as the label’s unit of measurement. Labels in other countries can use a different layout, including values per 100 g or 100 ml, so check the heading rather than assuming every column means the same thing.

Follow one column all the way down

Suppose a fictional package has two columns: 150 calories per serving and 300 calories per package. If you record the whole package, take the protein, carbohydrate, and fat values from that same whole-package column. Mixing calories from one column with macros from another creates an inconsistent entry.

If your portion falls between the listed amounts, use a multiplier. For a portion that is one and a half servings, multiply each per-serving amount by 1.5. The portion and serving guide includes examples with grams and homemade meals.

Keep grams separate from Daily Values

A gram value is an amount of a nutrient. A percent Daily Value is a reference for interpreting that amount in the context of a daily diet. It is not the same as the percentage of the food’s calories supplied by that nutrient.

For your food diary, use the calorie and gram fields requested by the app. Do not enter a label’s percent Daily Value into a gram field. For example, “10%” beside a nutrient does not mean the serving contains 10 g of it.

Compare like with like

To compare two products, first put them on the same quantity basis. Imagine Product A lists 120 calories per 30 g and Product B lists 150 calories per 50 g. The serving totals alone do not answer which has more calories for the same weight. Per gram, the examples are 4 and 3 calories respectively.

This is a comparison exercise, not a rule for choosing the lowest-calorie food. Consider what the food contributes to the meal, its other nutrients, how much you want to eat, and what you enjoy.

Check the entry against the package

Product recipes, package sizes, and database entries can differ. When a saved entry disagrees with the label in your hand, check the brand, flavor, serving amount, and whether the values describe prepared or unprepared food. A dry mix may have separate instructions for ingredients added during preparation.

Label values are not laboratory precision for your individual portion. Rounding and energy calculations can create small differences between printed calories and calories calculated from macros. Our macro guide explains why the quick calculation is only an estimate.

Sources & further reading

Written by the Calorify team for general education. Not individualized medical or nutrition advice. The examples are illustrative, not dietary targets. Read our editorial approach.