Why is measuring food using cups so inaccurate?

You know how people say to always weigh their food instead of using measuring cups to judge how much you're eating? Well I was wondering why measuring cups are so inaccurate. Like it makes sense that using a measuring cup to measure out 1 cup of flour could cause some discrepancy depending on how much the flour is packed down.

But what about foods that aren't so easily smushed such as cereal? Or others food like that. Is using a measuring cup that inaccurate? Do I really need a food scale to weigh out how much cereal I'm eating?

Replies

VintageFeline

https://youtu.be/XpHykP6e_Uk

jemhh

It is usually inaccurate because people jam a lot into a measuring cup. Think of packed brown sugar vs. brown sugar spooned into a cup, only just reaching the top of it. Most labels give you the nutrition info for a quantity of food similar to the loosely spooned brown sugar. Most people like to jam as much as possible into the cup, sometimes even spilling over the side and certainly heaped up top.

CyberTone

GoCleanGoLean wrote: »

You know how people say to always weigh their food instead of using measuring cups to judge how much you're eating? Well I was wondering why measuring cups are so inaccurate. Like it makes sense that using a measuring cup to measure out 1 cup of flour could cause some discrepancy depending on how much the flour is packed down.

But what about foods that aren't so easily smushed such as cereal? Or others food like that. Is using a measuring cup that inaccurate? Do I really need a food scale to weigh out how much cereal I'm eating?

Think about a box or bag of flaky cereal. When you get to the bottom of the box and pour out a cup of some flakes and mostly crumbs, a cup of that will weigh significantly more than a cup of flaky cereal from a newly opened box. The density of solids vary, so it is important to weigh anything that is in solid form.

sijomial

If you intend measuring weight then it's a bit of a roundabout method to use a measuring device for volume.
For some items it's going to OK but give grated cheese a try....

It was quite educational for me to weigh what I regarded as a serving of cereal and compare the weight to a serving as suggested on the packaging.

Digital scales are so inexpensive I would wonder why anyone wouldn't try one if they are serious about calorie counting. Doesn't mean you have to use them for life of course.

TimothyFish

GoCleanGoLean wrote: »

You know how people say to always weigh their food instead of using measuring cups to judge how much you're eating? Well I was wondering why measuring cups are so inaccurate. Like it makes sense that using a measuring cup to measure out 1 cup of flour could cause some discrepancy depending on how much the flour is packed down.

But what about foods that aren't so easily smushed such as cereal? Or others food like that. Is using a measuring cup that inaccurate? Do I really need a food scale to weigh out how much cereal I'm eating?

The theory is that since a measured cup of flour may weigh a different amount than another measured cup of flour that measuring with cups is inaccurate. The irony is that the people who make this claim never demonstrate that two cups of flour that weigh the same have the same number of calories in them. There is actually inaccuracies in weighing food as well.

There are a couple of different views on this. One is that we should get as close to accurate as we can, so we should weigh our food even though doing so gives us inaccurate calorie counts. Another view is that we should simply allow for inaccuracies and eliminate them by turning our attention things that are accurate.

I take the second view. Regardless of how inaccurate our measurement of food calories and calorie burns may be, the bathroom scale reveals the truth. If the bathroom scale is going up then we need to increase our calorie deficit. If the bathroom scale is going down then we need to decrease our calorie deficit. Using measuring cups and accepting the calorie counts listed on menus works great with this approach, but so does using a food scale.

vaman

Cups are great for liquid measure, but inaccurate for most dry goods. The density varies so greatly in many products. A cup of flour will increase in weight on a humid day and decrease on a dry day. Commercial bakeries always use the weight of dry ingredients when preparing a mixture.

Lizzy622

It tells you why right on the package. "Contents may settle during shipping"

zyxst

If you don't want to use a scale, don't.

JaydedMiss

way to many variables ....simple as that.

Ready2Rock206

Flour is one thing because it easily fits a cup but what is a cup of broccoli or a cup of chicken? Is it broccoli spears, chopped broccoli or are you just mushing it down so there's no empty space? Same with chicken - how are you making the chicken fit in the cup? Unless you make it into baby food a cup of chicken could vary wildly depending on what you're doing to get it in there.

cwolfman13

What does 1 cup of chicken look like?

CattOfTheGarage

There's also the fact that many cup measures have the line below the top rim, so you are supposed to fill them level to slightly below the rim. There is just so much room to heap it slightly or fill it just a little bit too deep and so create an error.

And it just gives you scope to cheat yourself. One podcaster I listen to said she was shocked to find, when she started weighing her food, just how adept she was at packing stuff into a cup measure - she said she had somehow found a way to fit a cup and a half of ice cream into a cup measure by squashing it down! (Ice cream contains air, remember - and so do many, many other things).

I'm not one of those who would ban eyeballing - I am actually a habitual eyeballer. But I have found over time that I have a talent for this, and I developed it by weighing portions regularly. I still weigh them at intervals to protect against creep.
And crucially, I know that by eyeballing I run a risk of underestimating, and if I stop losing, I'll know why and what to change.

So many people either eyeball or use volume measures without ever doing the necessary work of facing up to just how wrong their perceptions of portion size really are, so they are unwittingly kidding themselves. The only way to really see what a real portion looks like is with a scale. It will be a shock, but that shock is a necessary part of the journey - you can't skip it. If you try to, you'll find yourself on here asking why you're eating 1200 calories and not losing weight, and getting frustrated or insulted when people say "you're eating too much".

Muscleflex79

watch the video above or do the comparison yourself and you'll see exactly why.

markrgeary1

Cause the measurements are not repeatable.

estherdragonbat

Ok. So, I do a fair bit of baking and baking being a science, rather than an art, how many grams of flour, sugar, baking powder, etc should I use if the recipe calls for a cup? (Baking powder isn't bugging me that much; most recipes I make don't call for more than a teaspoon, so the calories per serving will be negligible. White and whole wheat flour and white and brown sugar are the biggies.)

CafeRacer808

estherdragonbat wrote: »

Ok. So, I do a fair bit of baking and baking being a science, rather than an art, how many grams of flour, sugar, baking powder, etc should I use if the recipe calls for a cup? (Baking powder isn't bugging me that much; most recipes I make don't call for more than a teaspoon, so the calories per serving will be negligible. White and whole wheat flour and white and brown sugar are the biggies.)

https://www.cooksillustrated.com/how_tos/5490-baking-conversion-chart

VintageFeline

estherdragonbat wrote: »

Ok. So, I do a fair bit of baking and baking being a science, rather than an art, how many grams of flour, sugar, baking powder, etc should I use if the recipe calls for a cup? (Baking powder isn't bugging me that much; most recipes I make don't call for more than a teaspoon, so the calories per serving will be negligible. White and whole wheat flour and white and brown sugar are the biggies.)

Or use UK recipes. Nary a cup in sight (I have one particular staple US recipe I had to go out and buy cups specifically for, they're not a staple in the UK kitchen arsenal).

estherdragonbat

Thanks!

unknown

This content has been removed.

TimothyFish

Here's a way to measure appropriate portion sizes without carrying a scale everywhere:

http://www.webmd.com/diet/healthtool-portion-size-plate

CyberTone

estherdragonbat wrote: »

Ok. So, I do a fair bit of baking and baking being a science, rather than an art, how many grams of flour, sugar, baking powder, etc should I use if the recipe calls for a cup? (Baking powder isn't bugging me that much; most recipes I make don't call for more than a teaspoon, so the calories per serving will be negligible. White and whole wheat flour and white and brown sugar are the biggies.)

This is the site I have bookmarked for baking conversions. It has the most comprehensive conversion list I have found yet.

http://www.kingarthurflour.com/learn/ingredient-weight-chart.html

CafeRacer808

CyberTone wrote: »

estherdragonbat wrote: »

Ok. So, I do a fair bit of baking and baking being a science, rather than an art, how many grams of flour, sugar, baking powder, etc should I use if the recipe calls for a cup? (Baking powder isn't bugging me that much; most recipes I make don't call for more than a teaspoon, so the calories per serving will be negligible. White and whole wheat flour and white and brown sugar are the biggies.)

This is the site I have bookmarked for baking conversions. It has the most comprehensive conversion list I have found yet.

http://www.kingarthurflour.com/learn/ingredient-weight-chart.html

Bookmarked for future reference!

rileysowner

GoCleanGoLean wrote: »

You know how people say to always weigh their food instead of using measuring cups to judge how much you're eating? Well I was wondering why measuring cups are so inaccurate. Like it makes sense that using a measuring cup to measure out 1 cup of flour could cause some discrepancy depending on how much the flour is packed down.

But what about foods that aren't so easily smushed such as cereal? Or others food like that. Is using a measuring cup that inaccurate? Do I really need a food scale to weigh out how much cereal I'm eating?

Two words, "Air space". It will vary from cup to cup for a variety of reasons when measuring solids. When you use a scale, it is not an issue. You can spread out the food, pack it together and everything in between and the weight will be the same. An honestly, once you get the hang of it, it is far easier than measuring cups and spoons.

savithny

estherdragonbat wrote: »

Ok. So, I do a fair bit of baking and baking being a science, rather than an art, how many grams of flour, sugar, baking powder, etc should I use if the recipe calls for a cup? (Baking powder isn't bugging me that much; most recipes I make don't call for more than a teaspoon, so the calories per serving will be negligible. White and whole wheat flour and white and brown sugar are the biggies.)

baking being a science is the reason that most of the "science of baking" cookbooks that I own strongly encourage getting a scale and using it. One book I bought in the 90s tried to make up for US cooks not having scales by specifying that *their* recipes require that you tightly pack flour into cups just like you do brown sugar. Most of the other ones just say "dude, get a scale if you want to bake all these great european pastries successfully."

ccsernica

estherdragonbat wrote: »

Ok. So, I do a fair bit of baking and baking being a science, rather than an art, how many grams of flour, sugar, baking powder, etc should I use if the recipe calls for a cup? (Baking powder isn't bugging me that much; most recipes I make don't call for more than a teaspoon, so the calories per serving will be negligible. White and whole wheat flour and white and brown sugar are the biggies.)

If you get European recipes, all these quantities will be specified by weight. So go across the pond for your ideas and you won't have to guess about converting.

FreyasRebirth

I weighed out steamed vegetables (from a bag) and their "1 cup" barely made a 1 cup measuring cup just over half full. That was... 2 days ago? Some things are just so wildly inaccurate you'd be eating almost twice what you should.

AnnPT77

And not weighing food is just fine, if you don't need to do it in order to be successful. Some/many people don't.

But here's the thing people often don't realize, if they want more precision than eyeballing:
Weighing solid food is quicker and easier than measuring with cups and spoons. You just need to know some tricks:

Assembling a salad in a bowl, a stew in a pan, sandwich on a plate? Put the bowl/pan/plate on the scale, zero, add an ingredient, note the weight, zero, add the next ingredient, note the weight . . . .
Using something from a carton or jar, or cutting a slice from a hunk of cheese? Put the container or chunk on the scale, zero, take out portion, note the negative value (it's the amount you took out).
Chopping something to add to a pan cooking on the stove? Chop, put cutting board on scale, zero, dump chopped food from cutting board to pan, put cutting board back on scale, note the negative value.
Eating a whole apple, banana, unhulled strawberries, corn on the cob? Weigh the ready-to-eat food, eat the yummy parts, weigh the core/hulls/peel, subtract & note.
I like to keep a few clean plastic yogurt-tub lids around to weigh small items, like a handful of nuts or chopped hardboiled eggs or something. Drop the lid on the scale, zero, add item, note weight, eat or use - just a quick rinse of the lid under the faucet & you're done.

No measuring spoons to scrape out, or wash, except when you need to measure liquids . . . and you can weigh some of them, too.

Quicker. Easier. More accurate.

lemonychild

Exactly. After being freaked out by the MFP community about not owning a scale I bought one and I didn't find the cups to be innacurate at all! However, I also didn't shove and stuff as much food when i used measuring cups

jemhh wrote: »

It is usually inaccurate because people jam a lot into a measuring cup. Think of packed brown sugar vs. brown sugar spooned into a cup, only just reaching the top of it. Most labels give you the nutrition info for a quantity of food similar to the loosely spooned brown sugar. Most people like to jam as much as possible into the cup, sometimes even spilling over the side and certainly heaped up top.

SusanMFindlay

Look_Its_Kriss wrote: »

Weighing food can actually be incredibly beneficial.

Example:

Recently i had been opting to buy store made bread because it's 50% cheaper then buying brand names like bens.

I bought a package of whole wheat whole grain bread and the nutritional information said for 2 slices (45g) was 150 calories.
Upon placing 1 slice of bread on the scale, which was not even from the middle of the bag the weight of 1 slice of bread came to 43g
A few thoughts came to mind.. Either the store made a typo in the grams weight and it should of read "90g" for 2 slices or the store made a typo and the package should say 1 slice (45g) is 150 calories.
When i contacted the grocery stores head office, they later confirmed that the bread was 150 calories for 1 slice not 2.

If i had not weighed this bread i would of been eating 150 unknown calories simply by believing the package saying 2 slices. with a 250 calorie deficit.. 150 calories pretty much wipes it away... instead of losing 2 pounds a month i would of only been losing a little over half a pound per month a stall in loss like that could result in a lot of people getting frustrated and quitting..

I've had this exact same experience too.

amusedmonkey

vaman wrote: »

Cups are great for liquid measure, but inaccurate for most dry goods. The density varies so greatly in many products. A cup of flour will increase in weight on a humid day and decrease on a dry day. Commercial bakeries always use the weight of dry ingredients when preparing a mixture.

I even weigh my liquids, because who has time for extra dishes?