How Are Serving Sizes Measured?

An egg might be considered one serving, while measuring cups will help measure serving sizes of other foods.
i Creatas Images/Creatas/Getty Images

While the U.S. Department of Agriculture offers recommendations for how much to eat of a certain food, its serving sizes may be different than those of food manufacturers. Those who make and package food must follow certain guidelines established by the U.S. Food and Drug Administration in determining what a serving size is for that food. That means food labels and the recommended dietary needs don’t always match, but the method of measure may be similar.

Dietary Guidelines vs. Nutrition Labels

    When the USDA considered dietary needs in developing the nutrition guidelines known as the Food Pyramid, now called MyPlate, it took into consideration four different factors: typical portion sizes as determined through food consumption surveys, ease of use of the measure, nutrient content of the food and tradition set forth in previous food guides. The goal of the Food Pyramid, then, is to guide you in meeting daily nutrient recommendations.

    Nutrition labels, on the other hand, aim to provide nutritional information for comparison with similar foods. The FDA requires food manufacturers to list serving sizes aligned with a common household measure, as well as the metric measure.

Consumption Amounts

    Food manufacturers begin the process of determining serving sizes by looking at what the FDA calls RACCs, or Reference Amounts Customarily Consumed, which is used to calculate the serving size for a product. The FDA has already set many of these RACCs. Food manufacturers look at these reference amounts and set their serving size to the closest measure included in the package. The serving size could be higher or lower than the reference amount, but the nutritional information, including calories, fat and fiber, is based on the actual serving size.

Common Measures

    The FDA asks food manufacturers to set serving sizes using cups, tablespoons or teaspoons – measurements commonly used in the kitchen. If those don’t work for a particular food, the FDA recommends using fractions of the food container, such as half a jar or a certain number of pieces or slices. Manufacturers can also list a serving size as measured by ounces. Food items that come in discrete units – like eggs and sliced meats – are listed as whole units, like one egg or four slices of ham.

Calculating Actual Servings

    You can use both the Food Pyramid and nutrition labels to help you get the nutrients your body needs and maintain or lose weight if you pay attention to serving sizes. If a serving size listed on the food label is one cup and you eat two cups, you need to double your calculations of the intake of calories and other nutrients. If you don’t want to measure foods daily, the USDA recommends using your bowls, plates and glasses to determine the serving sizes they hold. Pour cereal into a bowl, for example, to see how much you’d eat if you just filled the bowl. Then pour the cereal into a measuring cup to see just how big the serving size actually is. Or measure one cup of juice or milk and pour it into a glass to see what one cup of that liquid looks like in your glass.

the nest