How do food manufacturers calculate the calorie count of packaged foods? (2003)
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How do food manufacturers calculate the calorie count of packaged foods? (2003)
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Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#2The obvious next question then is how the protein and carbohydrate content is measured. That sounds like it would require more difficult analytical methods than bomb calorimetry and might not be worth the time and expense if it were not for the fact that those need to be reported separately on the label anyway.
Brief searching suggests that proteins are measured with a nitrogen content test and fats are determined by mixing the food with a non-polar solvent to see how much dissolves. Carbohydrates seem trickier and I haven't found a great explanation. Water solubility might work once the other components are removed.
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#3There are foods on which the standard processes don't accurately measure energy content. Or at least, certain manufacturers tell us that. Not sure if to believe them or not.
Example: Quest bars. Their syrup would typically show 4 kcal per gram, but is actually closer to 2. Supposedly. That's how a bar can have so few calories and such good macros.
Ultimately, if you're consistent with tracking your calories and its effect on your weight, it doesn't matter if the values are off by 20, 30, or 50%. Just be consistently off by... 50%.
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#4The obvious next question then is how the protein and carbohydrate content is measured. That sounds like it would require more difficult analytical methods than bomb calorimetry and might not be worth the time and expense if it were not for the fact that those need to be reported separately on the label anyway. Brief searching suggests that proteins are measured with a nitrogen content test and fats are determined by…
The protein test was famously faked with melamine in the Chinese dog-food scandal that killed dogs and resulted in a recall:
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#5The obvious next question then is how the protein and carbohydrate content is measured. That sounds like it would require more difficult analytical methods than bomb calorimetry and might not be worth the time and expense if it were not for the fact that those need to be reported separately on the label anyway. Brief searching suggests that proteins are measured with a nitrogen content test and fats are determined by…
Isn't the simpler & more plausible explanation that most individual foods aren't measured like that, but rather just by summing up the protein/carbohydrate/fat etc. amounts that go into making the food?
E.g. if you're making frozen pizza just add up flour, the pepperoni etc. you put in and divide it by portion size.
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#6The Gastropod Podcast just had a great episode about measuring calories:
https://gastropod.com/the-end-of-the-calorie/
"For most of us, the calorie is just a number on the back of the packet or on the display at the gym. But what is it, exactly? And how did we end up with this one unit with which to measure our food? Is a calorie the same no matter what type of food it comes from? And is one calorie for you exactly the same as one calorie for me? To find out, we visit the special rooms scientists use to measure how many calories we burn, and the labs where researchers are discovering that the calorie is broken. And we pose the question: If not the calorie, then what?"
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#7The obvious next question then is how the protein and carbohydrate content is measured. That sounds like it would require more difficult analytical methods than bomb calorimetry and might not be worth the time and expense if it were not for the fact that those need to be reported separately on the label anyway. Brief searching suggests that proteins are measured with a nitrogen content test and fats are determined by…
Isn't the simpler & more plausible explanation that most individual foods aren't measured like that, but rather just by summing up the protein/carbohydrate/fat etc. amounts that go into making the food? E.g. if you're making frozen pizza just add up flour, the pepperoni etc. you put in and divide it by portion size.
Pizza in particular is an interesting example because I would expect leavened bread products to be one of the cases where summing the components would cause more problems than usual (because you're going to lose sugar and other nutrients to the yeast). I'm not sure how many calories worth of carbs yeast consume during normal bread making, but I would expect it to be measurable. When making wine, yeast can easily consume pounds of sugar within days.
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#8Earlier quoted context omitted.
Isn't the simpler & more plausible explanation that most individual foods aren't measured like that, but rather just by summing up the protein/carbohydrate/fat etc. amounts that go into making the food? E.g. if you're making frozen pizza just add up flour, the pepperoni etc. you put in and divide it by portion size.
Pizza in particular is an interesting example because I would expect leavened bread products to be one of the cases where summing the components would cause more problems than usual (because you're going to lose sugar and other nutrients to the yeast). I'm not sure how many calories worth of carbs yeast consume during normal bread making, but I would expect it to be measurable. When making wine, yeast can easily cons…
Couldn't things like yeast be handled by some standard pre-computed approximate lookups?
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#9Earlier quoted context omitted.
Pizza in particular is an interesting example because I would expect leavened bread products to be one of the cases where summing the components would cause more problems than usual (because you're going to lose sugar and other nutrients to the yeast). I'm not sure how many calories worth of carbs yeast consume during normal bread making, but I would expect it to be measurable. When making wine, yeast can easily cons…
Couldn't things like yeast be handled by some standard pre-computed approximate lookups?
Definitely. You might not even have to consider baking time or temperature to get a good enough number to cover the calorie difference from lost carbohydrates and produced ethanol to meet the level of accuracy required for food labels.
I only brought it up in the first place because whenever a simple solution to a complicated problem is put forward, it will inevitably turn out that it's either not general enough or special cases need to be handled to keep it simple. There's nothing wrong with needing special cases, but it's always nicer to figure out what the special cases will be before someone does a bunch of architectural work that hasn't considered them.
Re: How do food manufacturers calculate the calorie count of packaged foods? (2003)
#10Earlier quoted context omitted.
Isn't the simpler & more plausible explanation that most individual foods aren't measured like that, but rather just by summing up the protein/carbohydrate/fat etc. amounts that go into making the food? E.g. if you're making frozen pizza just add up flour, the pepperoni etc. you put in and divide it by portion size.
Pizza in particular is an interesting example because I would expect leavened bread products to be one of the cases where summing the components would cause more problems than usual (because you're going to lose sugar and other nutrients to the yeast). I'm not sure how many calories worth of carbs yeast consume during normal bread making, but I would expect it to be measurable. When making wine, yeast can easily cons…
I suspect it's not a large effect for bread. My family bakes our own bread, and I would say without having measured it on a scale, that there's not a noticeable loss of weight from one end of the process to the other. Also, you'd notice the stuff bubbling if there were a significant production of CO2.
I've also made beer, and it bubbles like crazy once it gets working. One possible difference is that bread is made from (mostly) starch, whereas beermaking converts starches to sugars before fermentation, and the yeasts can work more efficiently on sugars.
Of course you can also load up commercial pizza with sugar... one of the reasons why we make our own pizza.