What’s the Difference Between Portion Size and Serving Size?

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What’s the Difference Between Portion Size and Serving Size?

In today's world, where portion sizes seem to be growing exponentially, it's crucial to understand the difference between portion size and serving size.

Many people mistakenly use these terms interchangeably, but they actually have distinct meanings. By understanding these differences, individuals can make more informed choices about their food intake and avoid overeating, which is a major contributor to the obesity epidemic.

To begin with, let's define each term.


Serving Size

Serving size refers to the standardized amount of food or beverage that is typically consumed in one sitting. It is a recommended reference amount set by regulatory bodies like the FDA (Food and Drug Administration) and is listed on nutrition labels to provide information about the nutrients and calories present in that specific portion of the food or beverage. Serving sizes are intended to help individuals understand and compare the nutritional content of different products.

The regulations and guidelines for serving size determination in the United States can be found on the official website of the Food and Drug Administration (FDA). The FDA provides detailed information on how serving sizes should be determined, including factors such as reference amounts customarily consumed (RACCs) and the "serving size" and "servings per container" declarations on nutrition labels. You can find more information on serving size regulations on the FDA's website.(1)


Portion Size

Portion size, on the other hand, refers to the amount of food or drink that is actually served or consumed by an individual during a particular eating occasion. Unlike serving size, which is a standardized reference, portion size can vary depending on personal preferences, cultural norms, and individual appetite. Portion sizes can be influenced by factors such as plate size, serving utensils, and social factors, and may differ from the recommended serving sizes. In fact, the American Heart Association reports that portion sizes have grown dramatically over the last 40 years.(2)

So, in simple terms, serving size refers to a standardized amount of food recommended by nutrition experts, whereas portion size refers to the amount of food an individual chooses to eat in one sitting. Or you can think of it as, serving size is a guideline provided by food manufacturers and nutrition labels, whereas portion size is determined by the individual.

While portion size recommendations are not regulated by a specific governing body, the Academy of Nutrition and Dietetics (AND) provides general guidelines for portion control and healthy eating. The AND offers resources and tips for portion control, including portion size guides for different food groups. These recommendations are based on scientific research and expert opinion in the field of nutrition. You can access information on portion sizes and portion control from the AND's website.(3)

Serving size is typically measured in familiar units such as cups, ounces, or pieces. It serves as a reference point for consumers to gauge the nutritional content of a particular food item. For example, a serving size of pasta may be one cup or 2 ounces, while a serving size of chicken breast may be 3 ounces. These serving sizes are determined based on nutritional guidelines and recommended daily intakes. They aim to provide individuals with a balanced diet and the necessary nutrients without excessive calorie consumption.

On the other hand, portion size is a subjective measurement that varies from person to person. It is influenced by factors such as hunger, cravings, emotions, and cultural norms. Portion sizes can be significantly larger or smaller than the recommended serving sizes. For example, a person might serve themselves a heaping plate of pasta at a restaurant, far exceeding the recommended serving size. Conversely, someone might limit themselves to a small side salad, significantly underestimating the appropriate serving size.(4)

Please note that specific countries or regions may have their own regulations or guidelines for serving and portion sizes, and it is recommended to refer to the respective governmental or authoritative sources for accurate and up-to-date information.

The American Heart Association reports that adults today consume an average of 300 more calories per day than they did in 1985.(2)

People might confuse serving size and portion size because both terms relate to the amount of food consumed, but they have different meanings and applications.


Here Are a Few Reasons for the Confusion

1. Similarity in Terminology

The terms "serving size" and "portion size" sound alike and are often used interchangeably in everyday language, leading to confusion. This can make it difficult for individuals to differentiate between the two concepts.


2. Lack of Awareness

Many people are not aware of the technical distinction between serving size and portion size. They may assume that both terms refer to the same thing, i.e., the amount of food they should consume.(5)


3. Influence of External Factors

External factors such as large portion sizes served in restaurants and fast-food establishments can contribute to the confusion. When people encounter these larger portions, they may perceive them as the standard serving size, even though they often exceed the recommended serving sizes.


4. Individual Preferences and Habits

Personal preferences and habits play a role in confusing serving size and portion size. Some individuals may use larger portion sizes than recommended due to their appetite, cultural norms, or past experiences, leading them to perceive their portion sizes as the standard serving sizes.(5)


It's important to understand that serving size is a standardized measurement, while portion size is the amount of food an individual chooses to eat. Understanding the difference between the two can help individuals make informed choices about their food intake and portion control.

The discrepancy between portion size and serving size can lead to overeating, as individuals often rely on external cues rather than their body's natural hunger and fullness signals.(6) The growing prevalence of larger portion sizes in restaurants and fast-food establishments has contributed to the normalization of oversized meals. As a result, individuals may unintentionally consume excessive calories, leading to weight gain and other health issues.

To combat the confusion between portion size and serving size, it is essential to develop mindful eating habits. Mindful eating involves paying attention to one's body and its signals, as well as being aware of portion sizes and making conscious choices.


Here Are Some Strategies to Help Individuals Make Healthier Portion Choices

1. Read Nutrition Labels

Nutrition labels provide information about serving sizes and the nutritional content of food items. By comparing the serving size on the label to the amount one typically consumes, individuals can adjust their portion sizes accordingly.


2. Use Measuring Tools

Measuring cups, spoons, and kitchen scales are useful tools for accurately measuring serving sizes. By using these tools, individuals can become more familiar with appropriate portion sizes and avoid overestimating or underestimating their food intake.


3. Practice Portion Control

Instead of relying on external cues or personal preference, practice portion control by consciously choosing appropriate serving sizes. For example, divide a large plate of food into smaller portions, and savor each portion mindfully.


4. Listen to Your Body

Pay attention to your body's hunger and fullness signals. Eat when you are hungry, and stop when you are comfortably satisfied, rather than finishing everything on your plate out of habit or social pressure.


5. Be Mindful of External Influences

Recognize that external factors, such as large plates, peer pressure, or advertising, can influence portion sizes. By being aware of these influences, individuals can make conscious choices that align with their health goals.


6. Practice Moderation

It's important to remember that no food is inherently "good" or "bad." Instead of completely eliminating certain foods, practice moderation by enjoying small portions of indulgent foods occasionally.


By understanding the differences between portion size and serving size and implementing these strategies, individuals can regain control over their food intake and make healthier choices. It's essential to prioritize nourishment and listen to our bodies, rather than being influenced by societal norms or external cues. With mindful eating and portion control, we can work towards a healthier future and combat the obesity epidemic that plagues our society.


1. Nutrition, C. for F. S. and A. (2023). Changes to the Nutrition Facts Label. FDA. https://www.fda.gov/food/food-labeling-nutrition/changes-nutrition-facts-label#serving_size. Accessed 14 September 2023.
‌2. Portion Size Versus Serving Size. (2015). Www.heart.org. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/portion-size-versus-serving-size. Accessed 14 September 2023.
3. Slide show: Portion control for weight loss. (2018). Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/weight-loss/multimedia/portion-control/sls-20076148. Accessed 14 September 2023.
4. The Supersizing of America: Portion Size and the Obesity: Nutrition Today. (2019). LWW. https://journals.lww.com/nutritiontodayonline/Abstract/2003/03000/The_Supersizing_of_America__Portion_Size_and_the.4.aspx. Accessed 14 September 2023.
5. Faulkner, G. P., Pourshahidi, L. K., Wallace, J. M. W., Kerr, M. A., McCrorie, T. A., & Livingstone, M. B. E. (2012). Serving size guidance for consumers: is it effective? Proceedings of the Nutrition Society, 71(4), 610–621. https://doi.org/10.1017/s0029665112000766. Accessed 14 September 2023.
‌6. Wansink, Brian and van Ittersum, Koert, Portion Size Me: Downsizing Our Consumption Norms (July 1, 2007). Journal of the American Dietetic Association 107.7 (2007): 1103-1106, Available at SSRN: https://ssrn.com/abstract=2474331. Accessed 14 September 2023.


Difference Between Portion Size and Serving Size Infographic
Difference Between Portion Size and Serving Size Infographic


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