Definition and Importance of the Serving Size

You may think you know what a serving size looks like, but it can be easy to eat more than you should because restaurants are in the habit of serving “super-sized” meals. The best way to be sure you’re eating the right amount of calories -- and to be confident you’re getting the nutrition you need to maintain a healthy lifestyle -- is to learn about the recommended serving sizes.


Developed by the United States Department of Agriculture, the serving size defines a specific amount of a particular food that represents the recommended portion for one sitting. The serving size creates a standard reference used on food labels.


The standardized serving size is one tool you can use to be sure you’re following a healthy, balanced diet. The United States Department of Agriculture determined that nutritional values be contained in the defined serving size. This information must be placed on food packages in the form of a Nutrition Facts label for easy access to information about the calories, fats, protein, fiber, carbohydrates, vitamins and minerals in one serving. Getting into the habit of reading the label helps you adjust your daily intake to meet your needs.

Serving Sizes

The first line on the Nutrition Facts label tells you what the serving size is for that particular food item, followed by the number of servings in that package. If you haven’t paid attention to the defined serving sizes, you might be surprised to discover that they are smaller, or possibly larger, than you realized. If you’re concerned about weight gain, compare the serving size with the portion you normally eat 1. You may discover you’re eating twice the number of calories you need each day. At the start, it may seem like a lot of information to compute, but serving sizes remain consistent 1. For example, one serving of meat is 3 oz., a serving of fruit is 1 medium-sized piece, a serving of bread is 1 slice, and for drinks and cooked vegetables, it’s 1 cup.


Some guides are available online that provide visual examples of serving sizes so you don’t have to worry about weighing or measuring your portions. One cup of cooked pasta is about the size of a tennis ball; one serving of hard cheese is 1 oz., which is the size of four dice; and a 3-oz. serving of beef, chicken or pork is the size of an adult’s palm, according to Loyola Marymount University.