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Finding densities and mass

  1. Jul 7, 2014 #1
    So i am a diabetic and i often need to find the amount of carbs in something, but because foods come in inconsistent sizes carb counts are usually configured my mass, however when i am out i don't readily have a scale on my person, so i am trying to find a way to find the mass of a food without using such a tool. At first i thought of working backwards from the density formula to find mass but i would need a density and not all kinds of the same food have the same density, so is there either a way to find the density of something without using p=m/v or is there some other way i could go about finding the mass? Anything is appreciated!
  2. jcsd
  3. Jul 7, 2014 #2
    I can't really think of any practical methods...

    By submerging your food in water and applying archimedes' principle, you can find it's mass, but you'd need a method for determining it's apparent mass under water.

    As I said, not very practical...
  4. Jul 7, 2014 #3


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    It's not clear which foods you are concerned about. Are you talking about eating a meal in a restaurant?

    Most prepackaged foods in the US are supposed to be labeled with sufficient information to inform the consumer about the total net weight, the number of servings in the package, the amount of sugars or carbs per serving, etc.

    In restaurants, this dietary information is supposed to be provided to the customer, either using a chart which is displayed or upon request.

    http://fnic.nal.usda.gov/consumers/eating-health/healthy-restaurant-eating [Broken]

    If you want to find the mass of your food, use a scale and weigh it directly. The value of the density of the food is typically not known a priori and must be calculated, using the mass of the food and the volume it occupies.
    Last edited by a moderator: May 6, 2017
  5. Jul 7, 2014 #4
    Not all restraunts are required to provide nutritional information, if they are not major chains or are small business (such as family run small town restraunts and such) so there is no give information, and that's what I'm talking about, the places where you do not know the information, and as I stated in the question I do not carry around a scale with me so I can't simply use the scale to measure the mass, I am looking for another way to find the ammount mass of something or the density or if possible to directly find the carbs (which I know is harder) and without destroying the food
  6. Jul 7, 2014 #5


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    I've been carb counting for many years in order to control my diabetes; you can follow the suggestions in this article to get close enough:


    Of course, eating at home is a more controlled environment, or preparing your own food to take with you for lunch.
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