Cup used for weighing food?

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Hi

I'm new to this forum. If this question belongs to another forum please accept my apologies and point me to the right place.

I do not understand the cup measurement used for describing weight. I asked support and they said “A cup is 8 fluid ounces, 236. ml, 226 grams”.

Now, every secondary school educated person knows that volume and weigh are not interchangeable and there certainly is no set conversion factor between them as it depends on the item's mass. Where do they come up with that 226 gram then?

I step into this issue when trying to calculate calories for some foods like cucumber, carrot, parsnip.

There is a database entry of 1 cup parsnips at 100 calories. According to support this would be translated to 226 grams, which means 100 grams of parnips is 42 calories. Meanwhile, the database has an entry for 1oo grams of Asda British parsnips at 123 calories. That is 2.9 times discrepancy on a vegetable which only a single variety exists. Can you see the problem? I think this caused by using wrong unit to measure items.

Besides, can you see yourself measuring a physical cup of parsnip, or cucumber, or carrots?

I like MyFittnessPal, especially the iPad app is great, but if the database is wrong the USP is gone and it becomes just a calculator.

Riza
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Replies

  • janejellyroll
    janejellyroll Posts: 25,763 Member
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    You should be using a scale, not a cup, to measure solid item.
  • erockem
    erockem Posts: 278 Member
    edited April 2015
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    Agreed, I got 2 different ones from ebay. Both still work great after 4 years. Paid less than $7 each w/free shipping.

    kitchen scales
  • Mycophilia
    Mycophilia Posts: 1,225 Member
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    This is why I read the nutritional info per 100g on the package of whatever I'm eating. Weigh the food, do some math and then make my own entry into the food diary.
  • aliciamariaq
    aliciamariaq Posts: 272 Member
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    When I first started out on MFP, this link helped me a lot to understand how and what to weigh. It totally makes sense and a lot easier than it sounds once you get the hang of it.

    http://community.myfitnesspal.com/en/discussion/1296011/calorie-counting-101/p1

  • TavistockToad
    TavistockToad Posts: 35,719 Member
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    You should be using a scale, not a cup, to measure solid item.

    This
  • ncboiler89
    ncboiler89 Posts: 2,408 Member
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    sarumbear wrote: »
    Hi

    I do not understand the cup measurement used for describing weight. I asked support and they said “A cup is 8 fluid ounces, 236. ml, 226 grams”.

    Now, every secondary school educated person knows that volume and weigh are not interchangeable and there certainly is no set conversion factor between them as it depends on the item's mass. Where do they come up with that 226 gram then?

    This is why the metric system runs circles around the US standard weights and measures because, to an extent, volume and weights are interchangeable. In the metric system one milliliter of water is one gram! It's the definition of a gram. So 236ml of water = 236grams. How awesome is that!? Of course that is only for water and is not as accurate as the specific gravity of the fluid changes however with almost any fluid you can get a reasonable estimation of the weigh by knowing the volume in metric units. For example if you weigh out 100 grams of milk you are going to be very close to 100 milliliters.

    However in the US system a fluid ounce and an ounce of weight are two different things and it's not a good idea to talk about them in the same context.

  • shadowfax_c11
    shadowfax_c11 Posts: 1,942 Member
    edited April 2015
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    Cups measure volume. Scales measure mass. You can't weigh anything with a cup.

    Use a scale to weigh your parsnips. Save the cups for measuring liquids.
  • Think of it this way. A sponge cake is light and fluffy because of its low density. A mud cake is heavy on the other hand and has a higher density.

    Imagine you've got a slice of each, same size and height.

    Put each on a set of scales on the other hand the outcome will be very different. The mud cake will weigh more because of the higher density. Same concept with fruit and veg.
  • Sorry if I got any mouths watering there!
  • TimothyFish
    TimothyFish Posts: 4,925 Member
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    You asked support for what?

    I have a scale that is supposed to be able to convert weight into cups, so I assume it uses some weight per cup number to determine that. But I never use that feature. For that matter, I rarely use the scale at all.
  • F00LofaT00K
    F00LofaT00K Posts: 688 Member
    edited April 2015
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    A cup does not measure weight. A "fluid ounce" is the volume of water needed to weigh one ounce. The use of the word "ounce" is kind of pointless because cups do not measure weight; they measures the volume of things. A fluid ounce of maple syrup will weight more than a fluid ounce of water. Fluid ounce is not weight and should only be used for measuring liquid portions like milk, beer, juice, etc.

    An actual scale that weighs grams, pounds, ounces, etc. measures the actual weight. This should be used for measuring the weight of solid foods like cereal, ice cream, vegetables, meat, etc.

    If you use cups to measure solid foods, you will get vastly differing results. A tablespoon of peanut butter typically has more calories than if you measure it by weight. I seem to get more ice cream if I weigh it than if I use a measuring cup. The serving sizes listed as cups are just a general reference to guide the eye. Most people don't know what 39g of oatmeal looks like... but they know what half a cup of oatmeal looks like. It is an estimate and nothing more. Weight your solids and be safe!
  • earlnabby
    earlnabby Posts: 8,171 Member
    edited April 2015
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    ncboiler89 wrote: »
    sarumbear wrote: »
    Hi

    I do not understand the cup measurement used for describing weight. I asked support and they said “A cup is 8 fluid ounces, 236. ml, 226 grams”.

    Now, every secondary school educated person knows that volume and weigh are not interchangeable and there certainly is no set conversion factor between them as it depends on the item's mass. Where do they come up with that 226 gram then?


    However in the US system a fluid ounce and an ounce of weight are two different things and it's not a good idea to talk about them in the same context.
    You are wrong. Water is the only substance with a specific gravity of 1, therefore an ounce of water also weighs an ounce, just like a liter also weighs a kilo. Now, if you are talking an ounce in the UK, that is different. A UK ounce is slightly larger than a US ounce which is why a UK pint is actually 19 US ounces rather than 16.

    ETA: I agree that grams is better for measuring


  • ncboiler89
    ncboiler89 Posts: 2,408 Member
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    earlnabby wrote: »
    ncboiler89 wrote: »
    sarumbear wrote: »
    Hi

    I do not understand the cup measurement used for describing weight. I asked support and they said “A cup is 8 fluid ounces, 236. ml, 226 grams”.

    Now, every secondary school educated person knows that volume and weigh are not interchangeable and there certainly is no set conversion factor between them as it depends on the item's mass. Where do they come up with that 226 gram then?


    However in the US system a fluid ounce and an ounce of weight are two different things and it's not a good idea to talk about them in the same context.
    You are wrong. Water is the only substance with a specific gravity of 1, therefore an ounce of water also weighs an ounce, just like a liter also weighs a kilo. Now, if you are talking an ounce in the UK, that is different. A UK ounce is slightly larger than a US ounce which is why a UK pint is actually 19 US ounces rather than 16.

    ETA: I agree that grams is better for measuring


    Thanks for the correction.
  • Dragn77
    Dragn77 Posts: 810 Member
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    You said it yourself...volume and weight are not interchangeable.

    You would not try to figure out how much you weigh with a tape measure, so why try to figure out how much food weighs using measurements for volume? Impossible. Weigh your food.
  • Zedeff
    Zedeff Posts: 651 Member
    edited April 2015
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    ncboiler89 wrote: »
    sarumbear wrote: »
    Hi

    I do not understand the cup measurement used for describing weight. I asked support and they said “A cup is 8 fluid ounces, 236. ml, 226 grams”.

    Now, every secondary school educated person knows that volume and weigh are not interchangeable and there certainly is no set conversion factor between them as it depends on the item's mass. Where do they come up with that 226 gram then?

    This is why the metric system runs circles around the US standard weights and measures because, to an extent, volume and weights are interchangeable. In the metric system one milliliter of water is one gram! It's the definition of a gram.

    Your "to an extent" caveat applies to only one substance which, ironically in this context, has zero calories and rarely has to be precisely measured. It is also funny that your example undermined the support response in the OP wherein a cup had different volumes and weights.

    The US system is silly, arbitrary, and horrendously outdated. The metric system is logical and scalable. Even if you're in the US, you should go metric for food measures.
  • ncboiler89
    ncboiler89 Posts: 2,408 Member
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    Zedeff wrote: »
    ncboiler89 wrote: »
    sarumbear wrote: »
    Hi

    I do not understand the cup measurement used for describing weight. I asked support and they said “A cup is 8 fluid ounces, 236. ml, 226 grams”.

    Now, every secondary school educated person knows that volume and weigh are not interchangeable and there certainly is no set conversion factor between them as it depends on the item's mass. Where do they come up with that 226 gram then?

    This is why the metric system runs circles around the US standard weights and measures because, to an extent, volume and weights are interchangeable. In the metric system one milliliter of water is one gram! It's the definition of a gram.

    Your "to an extent" caveat applies to only one substance which, ironically in this context, has zero calories and rarely has to be precisely measured. It is also funny that your example undermined the support response in the OP wherein a cup had different volumes and weights.

    No, the 'to an extent' does not apply to only water. It applies perfectly to water and to an extent to other liquids (such as milk). OP was confused about why 236ml is equal to 236 grams (because 8 ounces = 236ml = 236 grams I think OP mistyped when he she said 226 grams) when logically weights and volumes are two different things. I was pointing out that 236ml by definition is 236 grams and that metric volumes can be used to estimate the metric weights of other liquids.
  • jennifershoo
    jennifershoo Posts: 3,198 Member
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    Food scale.
  • sarumbear
    sarumbear Posts: 17 Member
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    I think I was not clear on the purpose of my post. I do know that cups and grams are not interchangeable and the the former measures volume, the latter weigh. My post is about why MFP doesn't? And, why they have so many entries with meaningless measures?

    Their USP of the app is the food database, which we can all agree that has many flowed entries. Why are their users, us, not complaining?
  • TavistockToad
    TavistockToad Posts: 35,719 Member
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    sarumbear wrote: »
    I think I was not clear on the purpose of my post. I do know that cups and grams are not interchangeable and the the former measures volume, the latter weigh. My post is about why MFP doesn't? And, why they have so many entries with meaningless measures?

    Their USP of the app is the food database, which we can all agree that has many flowed entries. Why are their users, us, not complaining?

    It's the users who have added the incorrect entries!
  • ncboiler89
    ncboiler89 Posts: 2,408 Member
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    sarumbear wrote: »
    I think I was not clear on the purpose of my post. I do know that cups and grams are not interchangeable and the the former measures volume, the latter weigh. My post is about why MFP doesn't? And, why they have so many entries with meaningless measures?

    Their USP of the app is the food database, which we can all agree that has many flowed entries. Why are their users, us, not complaining?

    I have never entered anything into the MFP database but I guess any user can. That means the user can put any unit of measure in that he or she wants (maybe there are some controlling parameters I don't know). So if I was going to put in some sort of dry cereal for example I guess I could put in one cup as the serving size. That's not a good idea but I could and MFP doesn't have control of that...at least not now. Maybe at some point in the future it will be smart enough to not allow this but who knows.