The Truth About Serving Sizes

Gain insight into the most misunderstood number on a food label.

Look at any Nutrition Facts label and you’ll see the words “serving size” right at the top. Most of us assume a serving size is the amount of food we should eat. Surprisingly, that’s not the case. Serving sizes aren’t recommendations handed down by a health authority. In fact, they aren’t recommendations at all.

So what are they, and how are you supposed to use them? Keep reading to find out.

The official definition of “serving size” is the amount of food that “can reasonably be consumed at one eating occasion.”

Who decides what’s reasonable? Surprisingly, we do.

The serving sizes you see on food labels are largely based on national surveys that ask Americans how much they eat at one sitting. Responses are analyzed and used to create a list of Reference Amounts Customarily Consumed (or RACCs). In turn, food manufacturers use RACCs to determine the serving size stated on a product’s Nutrition Facts label.

The short answer is because they’re based on old data. RACCs were established in 1993, using Nationwide Food Consumption Surveys conducted in the late 70s and 80s. As you might guess, we eat larger portions now than we did then.

Take a look at what we used to eat on average compared to now…

According to the latest regulations, anything less than two full servings in one container must be listed as one serving. That means a product that holds 1.9 servings would still say "Servings per container: 1."

The thinking is that if a container is fairly close to one serving, most people will finish the whole thing in one sitting.

Standard serving sizes are supposed to make it easier to compare similar products. Take ice cream, for example. Because one serving of ice cream is ⅔ cup (at least it is now — before the 2016 updates, it was ½ cup), you can look at two brands and easily compare the nutrition information.

If serving sizes weren’t standard, you might have to compare a ⅓ cup serving of one brand to a ⅔ cup serving of another. That’s tricky math.

(Keep in mind that that's exactly what you might need to do if you're comparing two products that list "Servings per container: 1," but each container holds a different amount.)

The best portion size for you will depend on what you’re eating and your health goals. See this resource for a general guide to portion size, and ask your coach if you need more detailed information.