- A new survey reports that most consumers do not know the difference between “portions size” and “serving size,” though many mistakenly believe they do.
- “Portion size” is defined as how much a person chooses to eat or drink. “Serving size” is based on a standardized amount of food or drink which is established by research done on the eating habits of adults and children.
- Understanding the difference between portion size and serving size can help you better manage your diet and make more informed choices about the amounts of food you eat during a meal.
When you go grocery shopping or plan on preparing your next meal, do you know the difference between “portion size” and “serving size”? If you confuse the two or think they’re the same thing, you’re not alone.
What is the difference?
Ali Webster, PhD, RD, director of Research and Nutrition Communications at the IFIC, told Healthline that “portion size and serving size are like siblings. They have a lot in common, but they’re also unique.”
She said portion size is defined as how much “you personally choose to eat or drink,” while “serving size is based on a standardized amount that people usually eat or drink, based on research done on the eating habits of adults and children.”
“We often encounter serving size information when we look at packaged foods — it’s right there on the Nutrition Facts label. Over time, it seems that many people have internalized that information as a recommendation for how much to eat when that’s not necessarily the case,” Webster explained.
“To illustrate, our research shows that regardless of the type of food, nearly half say they try to eat close to the serving size listed on packaging at least sometimes,” she said.
She added that “it’s clear that more effective communication is needed about the differences between these terms and how they can be applied to our eating habits.”
The survey published today uses data from interviews with 1,000 adults, ages 18 and up, conducted from Nov. 4 to Nov. 9, 2021.
It found that 9 in 10 people reported they had “at least some understanding of ‘serving size’ and ‘portion size,'” according to IFIC.
For one of the questions, participants were asked to identify “which statements best align with your understanding of serving size?” followed by a fill-in-the-blank of “serving size is ___.”
They found that:
- 48% said “serving size is” “based on a standardized amount of food or beverage that people typically consume in one sitting.”
- 46% said it’s “defined by the food company that creates the product.”
- 39% said it’s “defined by dietitians and health professionals.”
- 33% said it’s “defined by government agencies” like the FDA.
- 33% said it’s “how much of a food or beverage that you choose to eat in one sitting.”
These numbers are very similar to how people define portion size. The survey found that:
- 48% said it’s “based on a standardized amount of food or beverage that people typically consume in one sitting.”
- 45% said it’s “how much of a food or beverage that you choose to eat in one sitting.”
- 44% said it’s “defined by dietitians and health professionals.”
- 32% said it’s “defined by the food company that creates the product.”
- 29% said it’s “defined by government agencies” such as the FDA.
Following these questions, participants were given accurate definitions of the difference between the two terms. After reading the definitions, almost two in three said they “gained a better understanding” of the two topics.
“When we gave survey takers even the most basic of definitions of these terms, two in three said they understood more about portion size and serving size. This is a great example of both the need for nutrition professionals to help people understand more about their food choices and that the message doesn’t need to be overly complicated,” Webster said.
She noted that one key distinction to keep in mind is the fact that serving size is going to be “the same for everyone who looks at the package. The label says what it says.”
“But that amount may not match how much you want to eat or how much you need to eat to feel satisfied,” she added. “Practically, you can think of it this way: use the serving size to learn more about the nutritional attributes of the product, and use your own hunger cues, health goals, and personal preferences to find the right portion size for you.”
Elsewhere in the survey, around half of respondents said they “try to eat close to the serving size listed on packaging.” Additionally, most people said, when looking for information on “portion size” that they look to the “serving size” on the packaging.
Why is it so important to know the difference between the two terms?
Amber Pankonin, MS, RD, LMNT, registered dietitian and personal chef, told Healthline that it’s important to know the difference “because the nutrition facts information is based on a single serving.”
“If your portion size is larger than the serving size, it can be easy to underestimate the number of calories or nutrition you’re actually consuming,” she explained.
Webster added that “it’s important not to let the serving size on a product dictate how much you think you should be eating.”
“I think this is a big misconception — that the serving size is essentially a prescription for the ‘right’ amount to eat or drink,” Webster said.
“Serving size can be useful as a reference point, but the amount that you decide to eat — your portion size — should be personalized based on hunger cues, individual health goals, and other factors unique to you,” she said.
Pankonin added that these two terms can work well in concert with one another.
“The nutrition facts label of a product can be a terrific guide when picking the right portion size for you,” she said. “Portion size is the amount you choose to consume. The biggest difference is that you can control your portion size or how much you choose to consume, but the serving size will be consistent on the nutrition facts label.”
In the survey, most respondents reported weight control as the most significant reason behind their desire to pay attention to portion sizes.
In the survey, 36 percent of respondents said it “helps control my weight,” while 30 percent said it “helps me avoid eating too much of certain foods.”
On the other end of the spectrum, 17 percent said they don’t pay attention to portion sizes at all.
To help manage portion sizes, people try a range of methods, according to the survey.
This includes 34 percent of respondents who said they “try to eat more slowly,” an additional 34 percent saying “I stop eating when I feel full, even if there’s still food on my plate,” and 32 percent saying “I use smaller plates/bowls to reduce my portion size,” among other responses.
Among the people who don’t pay attention to portion size at all, 71 percent said it’s because “I don’t want to be too specific or place limits on how much I eat or drink.”
Other reasons included 33 percent who cited that “it is more important to not waste food than to have the right portion size.”
Finally, when given the choice between a larger container of food and a less cost-effective option of a pack of single-serving containers, most would go for the larger container.
When asked how understanding these two terms affects nutrition, Pankonin said that as a nutrition instructor, she makes a point to clarify these terms with her students in a Basic Nutrition course she teaches.
“Most students are surprised when they compare the serving size on a nutrition facts label to the portion size they would normally consume,” she said.
For her part, Webster said that “choosing appropriate portion sizes is a key part of following a healthy eating pattern.”
She explained that this is especially important when consuming “less nutrient-dense foods and beverages,” which tend to be “high in calories, added sugars, and sodium, for example.”
Webster has a few suggestions for how to apply all of this knowledge when grocery shopping or planning a meal.
“Before grocery shopping or meal planning, consider your preferences and your health goals and how they relate to your food choices. You might want to compare your typical portion sizes of different foods to amounts suggested by nutrition and health professionals, which can easily be found online,” she said.
“If that seems too stressful, think about what portion sizes make you feel most satisfied for different foods and how often you eat them, then take both into account when making your grocery list,” she said.
She added that many packaged food goods and beverages come in various sizes, including single-serve packaging.
“On top of helping us manage portion sizes, these options can be convenient and reduce food waste,” Webster said.
“Choosing smaller packaged versions of things like soda and indulgent snacks can also help reset our view of what appropriate portions should be,” she said, “making it easier over time to eat and drink amounts that promote healthier overall eating patterns.”