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Sunday 28th August 2016
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How do they count calories in food?


Gourmet foodMy friend Larry was eating a chicken and mushroom pie and I thought it must have been packed with calories. So how do they work out how many calories are in food?
Dave, Orpington


** Definitive **
Name: Frances, Putney
Qualification: My father invented the stainless steel canister involved
Answer: You take a measured quantity of the food and put it in a crucible with a copper wire inside it and drop it into a stainless steel canister, which is set in water. You then extract the oxygen and fire the copper wire which burns the food. You then measure the rate at which the water heats up. Essentially, it’s the burning a peanut experiment that you did at school on a bigger scale.

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