Do Serving Sizes Impact How Much We Eat?

by Elle Penner, MPH, RD
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Do Serving Sizes Impact How Much We Eat?

If the serving size for ice cream were to jump from 1/2-cup to 1-cup, would you eat more? Some experts are worried you might.

Among the proposed changes to the FDA Nutrition Facts label is the issue of recalculating serving sizes to reflect real-life consumption. In most cases, serving sizes would increase—ice cream and soft drinks are two products that would be affected. For example, those two servings in a 20-ounce bottle of soda would now be counted as one, since consumption data consistently shows people generally consume almost all, if not everything, of what’s in front of them. According to the FDA, “By law, serving sizes must be based on how much food people actually consume… not on what they should eat.”

This could be problematic given that more than half of consumers interpret “serving size” as a recommendation of how much they should eat or drink. This is concerning to the Behavioral Science and Regulation Group, a collection of students and fellows at Harvard, who told Food Navigator that while the changes may be “appropriate,”  this “could lead [consumers] to eat more than they otherwise would… because these consumers believe that the FDA has implicitly endorsed the serving size as healthy.”

The American Diabetes Association has urged the FDA, “to conduct consumer education to ensure these changes… are not misunderstood by consumers as recommendations to consume larger portions.” Consumer education campaigns could mean big bucks though. One alternative proposed by the Behavioral Science and Regulation Group could offer a simpler solution. “We suggest that the word ‘serving’ and the phrase ‘serving size’ be changed to avoid an implied endorsement. Changing ‘serving’ to a word that does not suggest the context of a meal, like ‘unit’ or ‘quantity,’ may mitigate the endorsement effect.” For example, rather than “Serving Size: 20 fluid ounces”, the Nutrition Facts Label on a soda bottle might read, “Quantity: 20 fluid ounces.

The proposed changes are currently open for public comment through August 1. Once the final changes have been agreed upon, food manufacturers will have 2 years to switch to the updated label.

For an overview of the other proposed changes, check out 6 Ways the Nutrition Facts Label May Change.

nutrition label serving size change

What do you think? Do serving sizes on labels impact how much you eat? Would the word “quantity” change how much ice cream you scoop from a carton?


  • Lizzy

    People who track calories and closely read labels probably treat the serving size as a guideline, but most people don’t. They will eat what is in front of them. It happens at restaurants as well. Our portion sizes at restaurants are huge and yet most people will clean the plate almost all the time. I think these new FDA nutrition labels are a good way to help average people understand how much they are really taking in, which could work out well.

  • g8rbaby

    I agree with Lizzy. Since I started the diet my nutritionist recommended, I pay attention to ALL the numbers on the Nutrition Facts. I am counting calories, carbs, protein, and fiber, so I am more interested in those numbers than serving size. I haven’t been logging my meals for some time, but in the first month of using MFP, I lost 7lbs. That was AFTER our regular monthly shopping and BEFORE we bought the kinds of foods recommended. I’m hoping my weight loss will be higher at my next visit, but I can live with 7lb a month! However, I am on the bipolar spectrum and I tend to have periods where I eat little to nothing for several days followed by binge eating.

  • Jim Chambers

    I like changing the serving size on sodas to one. I’ve never drank half a bottle and then put it away for later. I may nurse it through the day, but it will get finished. As far as changing it on things like the ice cream, I would keep it as it is right now. Using MFP has really changed what I view as a serving size. Keeping a meal to just one serving is much healthier than the way I used to eat.

  • Patricia Tierney

    Well no one just drinks half a pop and puts the rest away it goes flat yuck. But as for ice cream and treats I think they should stay the same or have cheep pre portion cups or maybe portion lines on everything telling u what a serving is so u don’t over eat. I find it hard to always count my chips or measure out a half a cup of ice cream every time I eat.

  • Charles

    I think the serving size changes are great! I think many people tend to misread or don’t pay attention to the serving sizes. This way, you can really just follow the caloric value more accurately and (for those of us with English degrees) avoid doing too much math!

  • Laura

    I think it’s an awesome idea. So many people are uneducated about nutrition labels and will often glance at the back of, say a coke, and see “120 calories” and assume it’s the entire bottle. If we get rid of the math and just put the number of what they are consuming in front of them they may become more aware of what they are actually putting into their bodies.

  • Tina Toburen

    I want to know nutrition information PER OUNCE so I can compare one food to another… then I want to know PER PACKAGE, so I know how much I may possibly consume in one sitting.

    Right now, it’s easy to convert the calories per serving x servings per container into a total per package value. Doing the math as calories per container divided by total ounces per container can also be done, nearly as easily.

    But for comparing foods side by side, a standard “size” needs to used, preferably on a mass basis, such as per Ounce (or 28-grams).

  • Josh Reid

    I don’t think anybody eats food based on the serving size. I’ve always been convinced food makers just lower the serving size to make their foods seem healthy when in fact they are high calorie. If you wanna affect food image. Make the whole container of whatever it is be the calorie count. Though as far as ppl counting calories, it is easier to count them when the serving sizes are smaller. But that’s really an afterthought.

  • SusanYounkin

    I agree we need to stop calling it “servings” as many people I talk to are confused by the term serving being used on the carton versus the term serving used in the food pyramid. As in: A “serving” of ice cream, is that a serving of dairy? The nutrition labels are really using typical American portion sizes, not any technical nutritional serving. Using portions, the “typical American” (if such a thing truly exists) most likely drinks the entire bottle of soda or most likely eats a cup or so of ice cream. So I agree that the terms are a bit inappropriate and would like to see the word portion used instead.

  • Julia

    I don’t really see the point in changing it. When I am restricting, I usually use the portion sizing unless it’s too high or too low. And then I may halve or double it. But until I started researching and trying to eat healthier I didn’t even know what a calorie was, let alone look at the labels. People should be educated more in schools at a young age about food nutrition and energy for your body. But even with that, people have to care enough to change their habits, so many people just don’t care or truly don’t believe they can lose the weight. I was one of those people until I understood the science behind it. I honestly thought I would have to have surgery or take a pill to lose weight. And now here I am, 120 lbs lighter, at a healthy weight. The media had made us think it is impossible without their products and surgeries and so many people ignorantly rely on them simply because they don’t understand the science behind weight loss.

  • Miskenny

    This is a good idea in terms of telling people how many calories is in what they actually eat/drink but I do agree that there also needs to be a standardized measurement for comparison (in NZ on drinks there is a standardized 100mL reading). I may suggest having a “per container” but then also a “per recommended serving size”.