How do food manufacturers calculate the calorie count of packaged foods? (2003)

The 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.<p>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&#x27;t found a great explanation. Water solubility might work once the other components are removed.

&gt; 9 Kcal&#x2F;g for fat. [...] These numbers were originally determined by burning<p>This method for calculating the calorie count for fat has in my opinion allowed the demonisation of fat.<p>Our stomachs are imperfect at digesting globules of fat. Burning-until-gone releases much more of the energy than surface acting acids and proteinases.<p>Effective calorie count for fat just has to be so much lower than the listed value.<p>Constrast that with sugars, where the absorbtion mechanism is crystaline dissolution. Disolving crystals is an almost perfect 1-1 process

&gt; The original method used to determine the number of kcals in a given food directly measured the energy it produced.The food was placed in a sealed container surrounded by water--an apparatus known as a bomb calorimeter. The food was completely burned and the resulting rise in water temperature was measured.<p>I don&#x27;t think the article addresses the following point. I may be totally wrong but I suspect the residues of the combustion still contain organic molecules that could possibly be broken down furthermore by some other process and release more energy (I believe it&#x27;s the case with fuel, I remember a chemistry teacher telling us that burning fuel was terribly inefficient).<p>Would it be possible that the digestion mechanism is somehow more efficient at breaking down this molecules and produce more energy than combustion?

In Poland it&#x27;s regulated, you can be off by 15%. My mate did tests in a lab. All products he picked showed 15% lower kcal value on the packaging.<p>I pick reduced fat houmous from the fridge. The label says 100g has 256kcal (18g of fat, 13g of carbs, 8,5g of protein = 248kcal)

Depends on what side of the package you&#x27;re reading.<p>On the back label its says calories per serving. On the front they use a different serving size to make it seem like it&#x27;s low-cal.<p>Like popcorn that&#x27;s 140 cals&#x2F;serving, but on the front it says 35 cals per <i>cup</i>.<p><a href="http:&#x2F;&#x2F;www.foodfacts.com&#x2F;ci&#x2F;nutritionfacts&#x2F;snack-foods&#x2F;smartfood-delight-sea-salt-popcorn-55-oz&#x2F;92496" rel="nofollow">http:&#x2F;&#x2F;www.foodfacts.com&#x2F;ci&#x2F;nutritionfacts&#x2F;snack-foods&#x2F;smart...</a><p>Or a pkg of 2 cupcakes is 380 cals, but they&#x27;ll say 190 cals per cake (in small type). It makes you think it&#x27;s 190 for the pkg of cakes.

This reminded me of a question I&#x27;ve always had... there&#x27;s always a lot of mass of the food not accounted for in the Fat&#x2F;Carbohydrates&#x2F;Protein&#x2F;Fiber. For example, a can of food that weighs 454g net might only have 150g accounted for in the nutrition facts. What&#x27;s in the rest of the food, besides water?

There are foods on which the standard processes don&#x27;t accurately measure energy content. Or at least, certain manufacturers tell us that. Not sure if to believe them or not.<p>Example: Quest bars. Their syrup would typically show 4 kcal per gram, but is actually closer to 2. Supposedly. That&#x27;s how a bar can have so few calories and such good macros.<p>Ultimately, if you&#x27;re consistent with tracking your calories and its effect on your weight, it doesn&#x27;t matter if the values are off by 20, 30, or 50%. Just be consistently off by... 50%.

The Gastropod Podcast just had a great episode about measuring calories:<p><a href="https:&#x2F;&#x2F;gastropod.com&#x2F;the-end-of-the-calorie&#x2F;" rel="nofollow">https:&#x2F;&#x2F;gastropod.com&#x2F;the-end-of-the-calorie&#x2F;</a><p>&quot;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?&quot;

Cooked food often have much more digestible calories than raw food. Because the heat breaks down complex molecules and make them easier to digest. This isn&#x27;t reflected at all in these measurements.<p>This is why it&#x27;s real hard to stay healthy on a raw food diet.<p>I learned this from this book, which I really recommend:<p><a href="https:&#x2F;&#x2F;www.amazon.com&#x2F;Catching-Fire-Cooking-Made-Human-ebook&#x2F;dp&#x2F;B0097D71MQ" rel="nofollow">https:&#x2F;&#x2F;www.amazon.com&#x2F;Catching-Fire-Cooking-Made-Human-eboo...</a>

I have a related question: Can the calorie count reliably predict the effect on a persons weight? Or is the amount of carbohydrates and fats much more important?

<i>&gt; ..you can also download the food database to a handheld compUter.</i><p>I&#x27;m going to start referring to smartphones as &quot;handheld computers&quot;.

This is a question that&#x27;s itched me constantly for over 15 years that I never bothered to look up. Anyone else?