|Portion and serving size are not synonyms, although many of us think of them as such. Because the words are used interchangeably we have become less accurate in judging just how much food we do eat and how many calories we consume.
There are in fact 2 different uses of the phrase serving size. In one meaning a serving size is a set amount of food determined by the USDA from which nutrients are calculated (calories, fiber, protein, carbohydrates…). The US government’s food pyramid suggests standard servings of various food groups so that you get a recommended amount of nutrients. The purpose of this information is to let you meet daily nutrient requirements.
There is also the serving size listed in the product nutrition information panel. This information is regulated by the FDA and can combine size of serving information from the USDA as well as information the manufacturer has on how much the average person eats of this product. Since the FDA began regulating nutrition fact panels the serving sizes have become more consistent, but can still vary considerably. This information is to educate the consumer and allow comparisons between products.
A portion is simply the amount of food you choose to eat at that time. Your portion of chips or carrots may be more or less than the amount identified on the nutrition panel and your portion may be larger or smaller than my portion. Your daily intake of food portions are determined by your Basal Metabolic Rate, activity, and ideal weight goal.
A serving size is not meant to tell you how much food to eat. It lets you calculate how many calories and nutrients you are getting based on the amount you eat. The USDA suggests that a serving of pasta is 1/2 cup cooked pasta, or 1 oz dry pasta. The box of pasta lists a serving as 2 oz dry, or 1 cup cooked. If you choose to eat 2 cups of pasta for dinner you are getting 4 servings according to the USDA amounts, but only 2 servings according to the nutrient label on the box of pasta (double the listed calories and nutrients).
The lack of consistent terminology is confusing, so know your portions sizes, read your nutrition labels, and keep fitness first!