What’s The Difference Between Serving Size And Portion Size?

by Katy Keogh, MS, RDN, LD

Last Updated: October 9, 2020

Many people come to us with the desire to learn about ‘portion control.’ With the various life changes the pandemic caused, many have experienced differences in eating habits. As some are consuming larger portions than in the past, portion control is top of mind as there is more free time to focus on making dietary changes.

We often hear patients ask, “How do I exercise better portion control?” or, “How much should I be eating?” It is a common belief in our diet and body-focused society that portion control is of utmost importance. Portions play a role in our health, and there is no doubt that portion sizes have increased in recent decades. However, it’s essential to look at the distinct definition and purpose of serving size versus portion size and approach these concepts in a different manner. The traditional approach to portion control is not always helpful or realistic long term. We find that if people try to rigidly control their portions, it’s just another diet that leaves little room for long-term success.

Serving size vs. portion size.
The terms serving size and portion size mean different things and are important for different reasons. Serving sizes are the amount of food used to calculate the information on the nutrition facts label. Serving sizes are regulated by law and are generally standardized for similar foods to improve the consistency and reliability of nutrition information on packages. Serving sizes are supposed to reflect the amount of food that the general population typically consumes on average. Note that this does not suggest that this is an appropriate amount for everyone. Here are some examples of standard serving sizes on the nutrition facts labels for different categories of foods:
  • Crackers and chips = 1 ounce
  • Pasta = 2 ounces
  • Milk and milk alternatives = 1 cup or 8 fluid ounces
  • Ice cream = 2/3 cup
  • Nuts = 1 ounce or 1/4 cup
  • Cheese = 1 ounce of hard cheese or 1/4 cup of shredded cheese

Portion sizes are not the same as serving sizes. Portion sizes generally represent either advice on how much you should eat or the amount of food you actually eat. Recommended portion sizes can vary for everyone and can be smaller or larger than the actual serving size. Many diets do have different recommendations regarding portion sizes. Sometimes portion sizes are listed in terms of standard measurements, like cups, ounces, tablespoons, or compared to other objects to help visualize the size. For example, we often hear, “Keep your portion of meat to the size of a deck of cards or the palm of your hand” or, “Keep your portion of nuts to one small handful.”

How much should you eat?
Good news – as mentioned above, the serving size is not always an indication of how much you should eat. We hear your sigh of relief! So then, what should your portion size be, and should serving size factor in at all? We’re not going to give you an exact answer because portion size is different for everyone and, to complicate it more, your optimal portion size differs by day, time, hunger, and other factors. Instead, we challenge you to throw out all previous food rules about portion size and ask that you think of yourself as an individual with unique needs. You know yourself best and you have the innate ability to know what is right for your body, if you simply stop and listen. If you are in tune with your body’s hunger and fullness signals, nourish yourself with generally balanced meals, include foods you enjoy, and eat regularly enough to avoid extremes in hunger. You can naturally figure out the portion that is right for you over time.

If you aren’t sure where to begin, serving sizes can be a helpful place to start. Begin by serving yourself the serving size listed on the package and then increase or decrease the amount based on how much your body feels it needs. Give yourself full permission to alter this amount as needed. If you struggle with these concepts or have differing medical or nutritional needs, for example, insulin-dependent diabetes, then it is wise to enlist the help of a Registered Dietitian skilled in intuitive or mindful eating.

How to exercise portion control.
If these concepts make sense to you but you find yourself feeling like you just need help controlling your portions, then it’s time to first look at what might be the cause. The concept of portion control may be the problem. Being too strict with serving sizes or portions often backfires and causes us to eat more. Portion control is just another form of restriction, and any restriction can sometimes cause a resultant binge in some way. If you are trying to stick to a specific portion size, it sends your body a message that you can’t trust its internal hunger and fullness signals to determine portion size on its own. As a result, you will be less able to listen to those signals telling you when to start and stop eating. Being in tune with your hunger and fullness signals, trusting your body, and giving yourself full permission to eat as much or as little as you want is the most important step to helping you eat the portion that is right for you. So, ditch the concept of ‘portion control’ or sticking to a serving size that someone or some diet told you to eat and start letting your body lead the way.

Finding your portion size.
Natural portion control is already built into our magnificent bodies as-is; we have to listen to it and nourish it in a food-positive and body-positive manner. Remember these four key points to naturally figure out the portions of food that are right for you over time:
  • Get in tune with your body’s hunger and fullness signals
  • Avoid extremes in hunger, eat regularly
  • Eat foods you enjoy, including treat foods
  • Nourish yourself with balanced meals most of the time (grains, proteins, fruits, vegetables, fluids)

Looking for more personalized guidance? Schedule an appointment with a Kroger Health Dietitian for an individualized plan specific to your needs.

Disclaimer: This information is educational only and not providing healthcare recommendations. Please see a healthcare provider.


Katy Keogh, MS, RDN, LD

Katy Keogh, MS, RDN, LD

A mom of 2 little kiddos and over 15 years’ experience in nutrition, Katy enjoys helping her patients squeeze good nutrition and activity into an already “full” life and find their own balance with nutrition and health while still enjoying food to the fullest. She is an expert in weight management, mindful eating, digestive health, anti-inflammatory nutrition, culinary nutrition, cooking/baking, and any other topic related to food! Outside of work, you’ll find her traveling, walking, jogging, beer tasting, and eating gelato.