When you’re monitoring and trying to improve your eating habits as part of your diabetes control plan, it’s important to know the difference between a serving size and a portion. A serving size is the amount of food listed on a product’s food label and it varies from product to product. A portion is how much food you choose to eat at one time, whether in a restaurant, from a package or at home. Sometimes the serving size and portion size match; sometimes they do not. If you are using an ADA diet exchange list, you will probably want to refer to the exchange sizes when deciding on how big your portion should be as part of your meal plan.
For example, according to a food label, one cup of macaroni and cheese is one serving. But if you make yourself a large bowl of macaroni and cheese, that portion is much bigger than one serving. The same may be true if you pour yourself a large bowl of cereal for breakfast. You should be the judge of how the portion you choose to eat relates to the serving size noted on the food label.
—Source: National Institute of Diabetes and Digestive and Kidney Diseases
Good Neighbor Pharmacy Health Connection, September 2014