A Dietitian’s Take on Weighing vs. Measuring Portions

Elle Penner, MPH, RD
by Elle Penner, MPH, RD
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A Dietitian’s Take on Weighing vs. Measuring Portions

Not paying attention to portion size is a surefire way to gain unwelcomed weight. Even when we think we’re being accurate about how much we’re eating, we tend to underestimate portion sizes according to research, particularly for beverages and “medium-energy density” foods like peanut butter toast and blueberry muffins.

However, both weighing and measuring food are effective ways to keep portions in check — and can be helpful techniques for those who are new to food logging or who are having a hard time estimating. But is one method better than the other? Let’s take a closer look at the differences between the two and the pros and cons of each.


Weighing food is certainly more accurate than simply taking a volume measurement because the amount of food you can fit in a measuring cup or spoon varies greatly. This is particularly true for more calorie-dense solid foods like nuts, proteins, starchy vegetables and certain fruits. For example, one cup of cubed avocado has 240 calories. But, how big of a cube are we talking about? If you dice it, chances are there are significantly more calories in that cup.

This may not matter much if you eat it only occasionally, but add a cup of diced avocado to your smoothie every morning and those calories add up over time. Brown sugar is another good example. One cup of loose brown sugar contains 551 calories. Pack it tightly, though, and that same cup has a whopping 836 calories, enough to impede weight-loss goals.  



Weighing is great because numbers — at least on food scales — don’t lie, but measuring utensils can undoubtedly be quicker and more convenient. Of course, some foods can be measured with accurately, particularly calorie-dense liquids like juice, milk, cooking oils and peanut butter since they always fill whatever measuring utensil you’re using and can’t be chopped too small, broken into pieces or tamped down.

You don’t need to weigh everything you put in your mouth, but if you’re new to portioning and tracking your food, it’s a good idea to weigh the more calorie-dense items at least until you become proficient at approximating amounts by volume.

Of course, if you’re trying to keep portions in check, any measurement is better than no measurement — or eating right out of the bag. If you have a food scale, great. If not, measuring cups and spoons — even your hand — can be effective in helping you control portion sizes and accurately track your food. In fact, doing a combination of all three can help you more accurately estimate portion sizes when you’re caught without your trusty food scale and measuring cups.

About the Author

Elle Penner, MPH, RD
Elle Penner, MPH, RD

Elle is a nutrition and wellness writer, recipe developer, blogger and nutrition consultant whose favorite things include her camera, carbs and quality time with her toddler. For more from this busy mama, check out Elle’s lifestyle blog or connect with her on Instagram, Pinterest and Facebook.


12 responses to “A Dietitian’s Take on Weighing vs. Measuring Portions”

  1. Avatar Jcook197 says:

    New ideas?

  2. Avatar Zaggin says:

    This is why imperial measuring system is fucking retarded for food.

    I hate it when I’m looking up a food or ingredient and it gives me measurements in cups or spoons…smh htf do you know how much food I can fit in there? It’s incredibly inaccurate and shouldn’t even be an option here for anything that’s not in liquid form

    • Avatar Tom Foogleflump says:

      So measuring out one liter is more accurate than 4 1/4 cups (actually 4.22 cups, but who’s counting .03 of a cup).

  3. Avatar Oliver says:

    The most inaccurate way of measuring food is in cups and spoons.

    • Avatar Tom Foogleflump says:

      So how else would you measure something?

      • Avatar Sytze Kamphuis says:

        Weigh it. If calories are based on the metric system what possible reason would you have to try and count them with a system based on something irrelevant. The entire article is even saying “Weighing is much more accurate, but I’m american and don’t like change”.

        • Avatar Tom Foogleflump says:

          Now you’re playing with semantics, “weighing” and “measuring” being the same, which isn’t necessarily so. My question was more related to, “What makes metric measuring any more accurate than Imperial?” Is x number of ounces any more accurate than y number of grams? The only difficulty I have is when calories are listed as “90 calories per ounce.” Is that an ounce by volume or an ounce by weight? In that instance, I can certainly see where the metric system would be clearer, but still not better. Most items (even ones in the US) would list it as “90 calories per ounce (28 grams)”. That clarifies that it’s a weight ounce and not a volume ounce. Problem solved (for me anyhow) 🙂

          • Avatar Sytze Kamphuis says:

            The metric system (or more properly the International System of Measurements; the metric system doesn’t technically exist anymore) is based on science. The pound is a consensus unit from a time when people didn’t understand that the universe is heliocentric. Well, almost consensus; there are still six or seven different types in use today including the US Conventional (since you technically don’t use the Imperial System either).
            The seven SI units are the basis of every other measurement we know of. This includes the imperial system since the US tried to cop out of its membership of the Metre Convention by defining its imperial measurements in terms of SI units. That means that using the imperial system when measuring food (and calories and macronutrients) is always going to have at least one conversion in it that will be rounded and you will be a little bit off in the endresult of how many calories are actually in there (not a lot, I admit, but it is more accurate to use grams).
            The fact that you needed to ask yourself “Is this an ounce by weight or volume?” is frankly an instant disqualifier for the US Conventional system. That should not be an issue and isn’t with metric (which is why american manufacturers probably use it).
            Scaling up with SI units is far easier since moving on to a new unit works on the decimal system (even our pounds and ounces: Kilogram=1000g, pound=500g, ounce=100g). Imperial goes with 16 ounces in a pound because reasons.
            The continued use of US conventional measurements is based on emotion, not reason.

            I would like to add that you responded to a post about using cups and spoons to measure with a question of how else you would measure it. If memory serves those are volume measurements so that did not make it obvious to me that you were asking about all the ways in which SI units are superior to US Conventional measurements. In light of the new information I’ll amend my answer to “Weigh it in (Kilo)grams”.

          • Avatar Tom Foogleflump says:

            Nice dissertation; I’ll give you an A on that one 🙂 Very interesting and informative.

            I DID respond to a volumes post, and you brought up the “Weigh it”. That’s fine, no problem there. It all kind of ran together with Zaggin’s post that follows this one, so I think that’s where the side-tracking started. But if a calorie count is given in a volume measurement (i.e., milk), how do you convert that to a calorie count by weight? I’m sure there must be plenty of web sites that would go through the trouble of converting it for you, but the apps like MFP and Lose It! aren’t going to, and I think that’s what most people use for calorie counting (not necessarily those two apps, but similar ones; I think you got my drift there).

            I managed to lose 26 US pounds between January 1st and March 31st using the Imperial measuring system, and have kept it off (+/- a pound or two) since, so I think I’ll stick with what works for me. I’m not saying your system is any worse, but I still don’t see where it’s any better either. That was the whole point I was trying to make.

            Thanks for your explanation of the ISM. I really DO find it interesting and informative; I wasn’t just trying to be a smart-ass 🙂

          • Avatar Sytze Kamphuis says:

            Thanks. Glad you enjoyed it and congratulations on shedding the weight. Portion control should work either way (especially compared to no portion control at all).

            I’ve run across sites and apps that do use cups and spoons to measure food, but then you have to give the volume of the specific foodstuff you’re using so that it can be converted to grams and then calories (and, yes, apps do this all in one go), but it is horribly inaccurate because of the variation that is possible with volume measurement. Given the gist of the article I think the author of that agrees with me (as do most, if not all of us commenting on it).

            I can tell you that following an american recipe is VERY frustrating if you live anywhere else in the world. It gets especially frustrating when they give you very specific caloric values (e.g. 293). I’m sure that you know the macronutrient gram to calorie ratios so I hope you can imagine the rest of the world screaming at their computer screens that the recipe has no right to labelling its caloric values that specifically when they basically come down to variations of a 1/4 of a gram or less which most kitchen scales can’t accurately measure. This brings down our confidence in volume measuring even further than we thought possible and that leads to the kinds of comments you see here.

            Didn’t think you were being a smart ass and we’re all here to learn, aren’t we.

  4. Avatar Amy says:

    Which food scale do you recommend?

  5. Avatar Anna says:

    I measure liquids with cups and spoons; and weigh everything else. I watched a video on here several years ago that convinced me to do mostly weights. The video pointed out that the amount of oatmeal that fits in a 1/4 cup measuring cup weighs more than the weight that the nutritional information was based off of. There were several other similar examples (and I think peanut butter was one of them). If the only option for a frozen vegetable in the database is 3/4 cup, I use the 91 grams on the package and do the math.

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