How can something have no calories? What does the body do with this calorie free food?
In: Biology
It cannot be broken down for energy. Some components, such as the water in it are absorbed by the body. As are some vitamins and minerals. But the bulk of the food item is passed through the body without being digested and is passed as fecal matter.
simplest way to understand it: calories are essentially a measure of energy. If it takes more energy to break down the food than the energy the food has stored in it, its calorie free, or calorie negative. For example, it takes more energy to chew celery than the celery has in it.
It’s also worth noting that a lot of “zero calorie” foods can actually have a non-trivial amount of calories.
[According to the FDA](https://www.fdareader.com/blog/2018/12/13/product-claims) (but I believe many other countries have similar regulations), if one “serving” of a food product has less than 5 calories, then you can label it as “zero calories” or “calorie-free” etc.
However, you might note that depends on the serving size. Any food product can be less than 5 calories if you eat a small enough portion of it. And indeed, some food companies do that: [Splenda packets contain as much calories as pure sugar, which is 4 calories per 1 gram](https://www.youtube.com/watch?v=EN6COaYLS_A), and surprise surprise, each packet of Splenda contains one gram, and thus can be labeled as “calorie-free”. Likewise, [Tic Tacs are almost pure sugar, but since one serving (i.e. a single Tic Tac, 0.49g) contains less than 0.5g sugar, they are allowed to be labeled as “sugar-free”](https://commonplacefacts.wordpress.com/2019/07/22/if-tic-tacs-contain-94-5-sugar-why-are-they-labeled-as-sugar-free/).
I’m not sure any food has actually 0 calories. A lot of vegetables like celery and arugula have very low <10 calories per cup. Despite the low calorie content, the body still has to break down a cup of arugula the same way it would a higher calorie food. It has to burn calories to extract the vitamins and minerals, digest, and pass it through the body. Even though the net calorie gain of eating a cup of arugula might be close to zero the body will still gain vitamin k, folate, etc
Calories are a measurement of how much useful energy can be extracted from a given amount of food. Some foods contain no chemicals that can be converted into mechanical energy. For instance, the artificial sweetener aspartame tastes like incredibly sweet sugar, but it’s actually a type of amino acid. The body can’t convert it into anything useful, so it passes through you as if it was water.
Calories are a measurement of energy, which comes from breaking bonds between atoms — mostly, carbon atoms. Just like the gasoline your car uses that makes it run (gasoline is primarily carbon and hydrogen). When your body breaks down things like sugar, fat, and protein, it breaks the bonds in it and releases energy that it uses to do various things.
Food has varying amounts of sugar, fat, and protein. A bag of Skittles is almost all sugar. A slab of meat is mostly protein, with some fat. All of those things have calories that come from those compounds, which your body breaks down.
Some foods do not have anything that your body can break down. Water, for instance, has no carbon. It goes in and most of it goes out (in your pee or your sweat). Some foods, like diet soda, have carbon compounds in it, but they are designed so they can’t be used by your body (they create the taste of sweetness but can’t be broken like normal sugar, hence no calories). And other foods have carbon, but it’s also in a form you can’t use — like celery, for instance, which is mostly fiber. It has substance, but (mostly) not a kind your body can break down and use. If your body can’t use it, there’s no energy to gain from it and therefore no calories.
Also, if you consume extra calories that your body doesn’t need at the moment, it uses that energy to make things to store and use later. One of those things is fat (your body can make fat). Then, if you go a while without eating, it will break that fat down and use it for energy. You don’t need to eat fat to make fat. Your body can use anything with calories (energy) to make fat. That’s why you can get fat even if you eat a fat free diet but eat a ton of sugar.
The work your body needs to do to mechanically breakdown (i.e. chew the food and lift it to your mouth) cost more or the same amount of calories as the food item. One common example is celery, which is mostly water therefore often described to be “0 or negative calories”
Another type is 0 calorie manufactured foods are just indigestible bulk, it goes through your body and comes out entirely without providing any nutritional benefit. It doesn’t have to break it down very far so the calories are minimal per serving.
This goes against equivalent exchange and other not fake sciences. Can you give an example?
No calories means that the body can’t digest anything and gain any energy. It’ll still get mixed in with other food and it’ll still exit in the normal manner. It just won’t give your body anything for its trouble.
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