It may be hard to imagine in today’s information age, but nutrition labels were not always displayed on packaged foods and beverages. The first Nutrition Facts label appeared on packages in May 1994, a few years after the Nutrition Labeling and Education Act was signed into law. The first update to the Nutrition Facts label since its inception was finalized in 2016, and it is this revised version that we see on most food and beverage packages today. Although official serving sizes appeared on the original label, individual portion sizes can differ from serving sizes, and confusion remains about the difference between the two. Let’s clarify those differences and trace how serving and portion sizes have changed through the years, how each is determined, and why each is important for our health.

Serving size vs. portion size: What’s the difference?

It’s easy to confuse serving sizes with portion sizes. They are sometimes used interchangeably, but they can represent different things. As we wrote in an earlier article, serving sizes listed on food labels are not advice for how much to eat; they are the amount that is used to calculate information on the Nutrition Facts label. Serving sizes displayed on the Nutrition Facts label are required by law to be based on the amount of a food or beverage that people typically consume during one eating or drinking occasion. These amounts are also known as Reference Amounts Customarily Consumed (RACC).

Portion sizes are not regulated by the government but often come in the form of advice from nutrition professionals. Ultimately, portion size is the amount of a food or beverage that you choose to consume. These choices can be influenced by multiple factors, including:

• The size of your tableware, including plates, bowls, cups and glasses
• The package sizes of the foods and beverages you purchase
• The person making and plating your meals—both at home when cooking for your family and at restaurants when dining out

How serving and portion sizes have changed

Both serving sizes and portion sizes have grown in recent decades, and you may have noticed the growth in portion sizes while shopping at grocery stores and eating out. Today’s standard restaurant portions, be they served at quick-serve, fast-casual or casual establishments, are significantly larger than they were a half-century ago. The shift toward larger portion sizes has also occurred outside the restaurant setting. In stores, the size of items such as individually packaged muffins, bottles of soda and bags of chips have also increased significantly over the years. The origin of this trend is hard to pinpoint, but one example comes from the 1960s, when movie theaters began offering larger container sizes of popcorn because movie-goers would not typically purchase more than one carton. The concept was new, but it became apparent that Americans were willing to pay a higher price for larger sizes if given the option. People saw value in larger sizes and responded by ordering them more often, as opposed to ordering multiple smaller orders. Over time, this purchasing behavior became the norm.

Because the growth in portion sizes is more visually apparent, you may not have noticed serving size changes as much. Serving sizes have recently been updated for use on the Nutrition Facts label to better reflect our current consumption habits. Before these updates were finalized in 2016, serving sizes were based on consumer surveys conducted in the late 1970s through the 1980s. Because we consume more of certain foods and beverages than we used to, serving sizes have changed for many products. For example, the serving size for ice cream has increased by 33 percent, from a half-cup to two-thirds (2/3) of a cup. This means that a pint of ice cream now lists three servings instead of four. The serving size for most beverages (e.g., coffee, soda, tea and water) has increased by 50 percent, from eight ounces to 12 ounces. Juices and milk servings sizes are still eight ounces.

The consequences of larger portion sizes

Larger portion sizes and increased consumption have impacted health in America and worldwide. Along with gradual increases in portion sizes and the acceptance of larger portion sizes as the norm, total caloric intake has increased, contributing to negative health outcomes such as excessive weight gain and the disruption of satiety cues. In addition to the impact on our personal health, large portion sizes have also contributed to increased food waste, which has a negative impact on the health of our planet.

Buying foods and beverages in large portion sizes or being served large portion sizes can nudge people to eat beyond their satiety (sense of fullness). Often, people feel obligated to finish a beverage or food container or clean their plate regardless of the size of the portion, even if their body signaled them to stop eating while there was still food on the plate or in the package. Selecting smaller portion sizes is a practical and effective way to help people reduce their intake. When selecting smaller portion sizes of foods and beverages is not an option, practicing mindful eating may be another strategy that can help people more easily identify when they feel full, even when faced with a large portion. Choosing smaller portions and practicing mindful eating can address two important issues: reducing the number of calories we eat as well as cutting down on the amount of food we waste.

Reversing the portion size trend

Increasing nutrition education and boosting awareness of the importance of making informed personal choices are common strategies for improving the health and diets of Americans. But our food environment also impacts our choices. Reducing portion sizes to make smaller portion sizes become the “new normal” has been proposed by experts as one approach to weight management. Based on sound scientific evidence, many reputable international organizations support decreased portion size as both effective and sustainable for reducing obesity. Perhaps even more beneficially, reducing portion sizes may aid the re-normalization and acceptance of smaller portion sizes in our diets.

Moreover, research institutes support interventions that rely on changes to the food environment that can positively shape people’s choices. While single interventions vary in cost and cannot match the collective impact of multiple simultaneous interventions, there are some that can have a more significant impact than others. According to a 2014 report from the McKinsey Global Institute, portion control is one of the most cost-effective interventions for promoting behavior change and reducing obesity. Larger policy changes to help make smaller portion sizes a reality at the population level could amplify the effect of positive changes achieved at the individual level.

One initiative that has brought together leaders from academia, government, non-governmental organizations and industry in the U.S. is the Portion Balance Coalition (PBC). The PBC is a multi-sector group organized by Georgetown University that seeks to address obesity by focusing on the volume (size), proportionality (variety), and quality (nutrient density) of foods as a means to promote healthier eating.

Deciding how much to eat and drink

Because serving sizes listed on Nutrition Facts labels can easily be misinterpreted as advice, and because eating out sometimes means navigating large portion sizes, it’s understandably difficult to determine the right amount to eat and drink. Here are a few tips to help you figure out what’s right for you:

• When grocery shopping, consider choosing foods and drinks in smaller package sizes.
• When eating out, try choosing smaller portions when available—or sharing entrees. You can always order more if the smaller portion isn’t enough.
• Allow smaller portions to become your “new normal” again.
• Eat slowly to allow your hunger and satiety cues to kick in. Pay attention to these cues to know when you’ve had enough. With practice, you can become more in tune with the amount of food it takes for your hunger to be satisfied.
• Use our eat-moji scale to help identify your level of fullness.
• Use mindfulness to understand your own body’s needs when it comes to portion sizes.
• Use tools like the National Institutes of Health Body Weight Planner to help you balance your calorie intake and activity level.
• Use the Nutrition Facts Panel to understand the nutritional value in each serving.