The Truth About Serving Sizes

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.


Q: What does serving size really mean?

A: 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 RACCs or Reference Amounts Customarily Consumed. In turn, food manufacturers use RACCs to determine the serving size stated on a product’s Nutrition Label.


Q: If serving sizes are based on what we eat, why are they so small?

A: The short answer is because they’re based on old data. RACCs were established in 1993, using Nationwide Food Consumption Surveys conducted in in the late 70s and 80s. To say that we eat larger portions now than we did then is a major understatement.

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


1980s 2000s
Bagel 140 calories 350 calories
Muffin 210 calories 500 calories
Cheeseburger 333 calories 590 calories
Soda 82 calories 250 calories
Spaghetti & meatballs 500 calories 1,020 calories


In response to more recent surveys conducted between 2003 and 2008, the FDA decided that RACCs were due for an update. Any stated serving size that is 25% smaller than what people report eating now would have to change.

The catch is that manufacturers are not required to comply until  2021, so you’ll continue to see some miniscule serving sizes until then.


Q: Whoa, so serving sizes are getting bigger? Won’t that encourage people to eat more?

A: Not necessarily, at least according to one study. Researchers presented a bowl of M&Ms along with the candy’s Nutrition Label to two groups of people.

The first group saw a label that listed a smaller serving size. The second group saw a label with a larger serving size. The latter group ended up eating less in one sitting.

It could be that when we’re faced with a tiny serving size, we’re more likely think “I’m already eating more than I should, so I might as well go hog wild.”


Q: I’ve seen “servings per container: 1” on both a 12 ounce can and 20 ounce bottle of the same kind of soda. How can that be?

A: According to the latest regulations, if a packaged food or beverage contains up to 2x the RACC, it must be listed as 1 serving per container.

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


Q: What are servings sizes good for, exactly?

A: Standard serving sizes 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 compare the nutrition 1:1.

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


Q: How do I find out what a healthy portion size is for me?

A: In Omada, we cover healthy portion sizes in Week 4. At this point, we encourage you to boost your intake of fruits and vegetables, drink more water, and eat fewer empty calorie foods.  

If you can shrink your usual portion of soda, juice, candy, pastries, donuts, pizza, ice cream, and heavily processed meats like hot dogs and sausage, that’s an improvement.

If you can avoid these foods altogether, that’s even better. Start where you are and do what you can.




FDA. Food Serving Sizes Get a Reality Check. Updated August 18, 2016. Accessed June 7, 2018.

National Heart, Lung, and Blood Institute Obesity Education Initiative. Portion Distortion II.

The effects of increased serving sizes on consumption. Appetite. 2016 Jun 1;101:71-9. doi: 10.1016/j.appet.2016.02.156. Epub 2016 Feb 27.