Serving versus portion
Two words get mixed up constantly. A serving size is a standardized reference amount shown on a food label so that products can be compared. A portion is the amount you actually put on your plate or eat from the bag. They are often different, and the label never tells you what your portion should be.
In the United States, label serving sizes are based on amounts people typically eat in one sitting, according to national food surveys, not on what anyone recommends. That is why a serving of ice cream, cereal or pasta may look smaller than your usual bowl. The serving size is a measuring stick, not advice.
Why it matters when reading a label
Every number on a Nutrition Facts panel (calories, fat, sodium, sugars, fiber) applies to one serving. If you eat more or fewer servings, the numbers scale accordingly. Looking only at the calorie line without checking the serving size is one of the most common mistakes when reading nutrition labels.
Scaling the numbers
The calculation is just multiplication. A hypothetical example: a bag of snack mix lists a serving size of 1 cup, 3 servings per bag, and 200 calories and 300 mg sodium per serving. If you eat the whole bag, that is 3 times 200, or 600 calories, and 3 times 300, or 900 mg of sodium. If you eat half the bag, that is 1.5 servings, so 1.5 times 200, or 300 calories, and 1.5 times 300, or 450 mg of sodium. These figures are made up for illustration; check the real package.
You can apply the same math to percent Daily Value. If one serving is 15 percent DV for added sugars and you drink 2 servings, you get about 30 percent.
Servings per container
Near the top of the label, “servings per container” tells you how many servings the package holds. A package that looks like a single serving, such as a 20-ounce bottle of soda or a pint of ice cream, may contain more than one. Some packages say “about” because the count is approximate.
Rules in the U.S. require that certain packages that could be eaten in one sitting, within a defined size range, be labeled as a single serving. For packages that are bigger than a single serving but could reasonably be consumed at once, many labels now use dual-column formatting. One column shows values “per serving” and another shows “per package,” so you do not need to multiply yourself.
Why your portion may be bigger (or smaller)
- Package sizes and plate sizes have changed. Larger packages and larger dinnerware make big portions look normal.
- Serving sizes reflect typical eating, not ideal eating. The reference amount may be bigger than needed for some people and smaller than what an active person wants.
- Different foods use different units. A serving of cereal may be a cup, a serving of cheese an ounce, and a serving of crackers a number of pieces.
- Appetite and activity vary. A teenager after a long practice and an office worker with a light day may reasonably eat different amounts.
Because of this, portion size is personal. The article on portion awareness covers ways to judge how much you are eating without weighing everything.
Practical ways to use servings
- Check before you open. Look at the serving size and servings per container before you start eating.
- Pour a serving into a bowl rather than eating from the bag or box, if you like. That is a simple way to see how much you are eating. Some people find it useful and others find it fussy, so use it when it helps.
- Use measuring cups occasionally to calibrate your eye. Measure your usual bowl of cereal once and you will know what it holds.
- Compare products at the same serving size. If two brands use different serving sizes, the per-serving numbers are not directly comparable. Use the weight in grams, or scale to the same amount.
- Do not forget add-ons. Oil, butter, dressing, cheese, sauces and toppings are additional servings that are not on the label of the main food.
Beyond the label
Serving sizes on labels are a tool for comparison; they are not a diet plan. Some people find that counting servings helps them, and others find it distracting or stressful. Listening to hunger cues and eating without distraction, as described in the guide to mindful eating, offers another way to judge how much is enough. If you are managing diabetes, kidney disease or a weight-related health concern, a registered dietitian can help you find portion targets suited to you.
Fresh foods and restaurants
Foods without labels, such as fresh produce, plain meat and restaurant dishes, have no printed serving size. In those cases, general visual guides (like a fist for a cup of cooked grains or a deck-of-cards-sized portion of meat) are rough shortcuts, though they are not exact. Many restaurant meals contain more than one typical serving, and sharing or taking half home is a common approach to restaurant meals.