• Question: how do people know how much nutritian, calories, fat are in each food product which they maunufacture for others?? even in liquids. Go they test each on thek and that determines how much is in that product?? 10kniwilc

    Asked by 10kniwilc to Daniela, Hannah, Ian, Jono, Mark on 25 Jun 2013.
    • Photo: Mark Hodson

      Mark Hodson answered on 25 Jun 2013:

      Hi 10kniwilc,

      they can measure all these things – there’s a whole branch of science, related to biology and chemistry, called food science.

      It’s amazing that really it’s only relatively recently that we’ve learnt about nutrition.

      I’m interested in polar explorers and expeditions like Scott’s to the Antarctic had really bad nutrition because they simply didn’t understand food properly or how much fat, fibre and calories people needed everyday.



    • Photo: Hannah Brotherton

      Hannah Brotherton answered on 25 Jun 2013:

      Hi 10kniwilc,
      So did you know in a can of coke there is half a can of SUGAR!!!! I am never drinking coke again lol.

      So calories is just a measure of energy – Specifically, a calorie is the amount of energy, or heat, it takes to raise the temperature of 1 gram of water by 1 degree Celsius (1.8 degrees Fahrenheit).
      So when people first make microwave foods or actually eat anything – they burn it and see how much it increases the temperature. So 1 calorie increases water temperature by 1 degree…..so if it raises it be 299 degrees it is 299 calories

      So is that how they worked out all the McDonald calories – that is a lot of burning fries 😛

    • Photo: Ian Wilson

      Ian Wilson answered on 25 Jun 2013:

      Hi 10kniwilc,

      Working out how much protein and carbohydrate etc involves doing some chemistry experiments. They mix a known about of the food with various liquids and chemicals and measure the output.

      Nowadays, calorie content is worked out using a series of calculations. We know how many calories are in 1g of protein and fat and so on, so we can work out the number of calories. But that’s boring!

      The far more entertaining way of getting an idea of the number of calories is to BURN THE FOOD!! Mwahahaha!!

      Scientists used to do this, sticking the food in something called a ‘Bomb Calorimeter’ and measuring the heat produced by the flame. The longer something burns and the more heat it produces, the more calories it contains. Check out the video below for a good demo.

      Hope that helps!