Eli5: How can edible items have 0 calories in them while still contain nutritional items like carbs (sugars and other sweeteners), vitamins, and amino acids (BCAAs etc.)?



Eli5: How can edible items have 0 calories in them while still contain nutritional items like carbs (sugars and other sweeteners), vitamins, and amino acids (BCAAs etc.)?

In: Chemistry

You can’t have carbs and 0 calories. You can have artificial sweeteners, but that’s the opposite of “nutritional”.

They can not:

Carbs have 4.5 calories a gram.

Protein has 4.5 calories a gram.

Fat has 9 calories a gram.

Calories are allowed to be rounded on labeling in the U.S.; but unless something has so little macro-nutrients that it has less than 0.5 calories, it will have calories to have any nutritional value (nutritional value is not the same as supplemental value – like the zero calorie multi-vitamin that has lots of micro nutrients).

However, they are some chemical sweeteners that do not have calories, but the health damage from them is vast, and they are best to be avoided. There are natural and lower calories sweeteners that are acceptable (honey, stevia, coconut sugar, etc.), but the zero cal sweeteners are generally carcinogenic (cancer causing) and best completely avoided.

They can’t really have 0 calories, but they could theoretically have 0 *net* calories. This means that the amount of energy you get from the food is equal to the amount of energy it takes your body to digest it. So, effectively, it does nothing for you.

Imagine you’re buying and selling items at a market. If you sell an item for the same price you bought it, you have a profit of £0 even though someone gave you money for it. This is like the net calorific value.

Simple: They (or at least most food) can’t.

The amount of vitamins in food is usually small enough that it doesn’t matter, so their caloric value might as well be 0 although they’re considered nutrients. And most artificial sweeteners really have 0 or close to 0 caloric value. Table salt is edible (in small amounts) and has 0 caloric value, and of course plain water is drinkable and also has no calories.

But carbohydrates have calories pretty much by definition, as do amino acids. If you’re eating any of those, you’re eating calories.

they round down fractions by servings so like 1 serving might be zero cals for anal items but you eat so many that it makes a few but each serving has zero

You have two things going on here.

1. The label can round down. So if there are 0.499 Calories in a serving it can list 0. Bonus: Serving sizes for a lot of items are arbitrary so they adjust the serving size to hit the 0 Calorie rounding sweet spot

2. Artificial sweeteners are in there in very small amounts. I forget the numbers but an easy way to explain it is that the artificial sweeteners are thousands of times sweeter than regular sugar, so you only need very tiny amounts to make something very sweet.

Obviously number two has a lot of nuances and complicated things going on, but that doesn’t belong on ELI5.

This also has to do with a conversion “glitch” and the United States’ relative reluctance to adopt the metric system. In US food labels, there’s a technical distinction between little-c calories and big-C Calories. What we see in FDA nutritional labels are big-C Calories, which are technically **Kilo**calories. Since the US is always weird about the metric system, they decided to just avoid that Kilo altogether and make it even more confusing.

So, combine that with fast-and-loose rounding and you get 0 big-C Calories =< 999 little-c calories.

>What is the difference between calories and kilocalories?

> The “calorie” we refer to in food is actually kilocalorie. One (1) kilocalorie is the same as one (1) Calorie (upper case C). A kilocalorie is the amount of heat required to raise the temperature of 1 kilogram of water one degree Celsius.


If a product is below like 15 calories per serving, it can be labeled as 0 calories. Coffee is famous for having zero calories when it’s actually 5-10 calories a serving.

Tic Tacs infamously list a single mint as the serving size, so despite being little sugar pills, they’re printed as 0 calories.

Alot of foods are allowed to be zero call because laws allow under 5cal to be rounded down, small portion sizes allow this despite them being basically all sugar (looking at you tic tac)

I would also like to point out that some foods such as a grapefruit have calories but it actually takes more calories to digest than they have effectively giving you zero or very low calorie food.

As a diabetic who lives by counting carbs, I’m pretty sure you can’t have 0 calories but have carbs. If something is 0 calorie, I know that I can eat/drink it without needing insulin. No idea of the science, but basically carbs provide calories, or calories provide carbs.

And sweeteners contain extremely few carbs – it’s why diabetics use them, rather than sugar.

I know this doesn’t answer the question, but I felt it was an important thing to point out, in the interests of full education. Kinda.

Calories are the gasoline for you body. You also need windshield wiper fluid, brake fluid, and oil. If your body can’t use it for fuel, then it has no Calories.

This is why in the EU and other places the amount of calories, carbs and sugars, proteins, salt, fat and saturated fat, and fibre **MUST** be reported per 100g. And the net weight must also be present.

They may also give these values per “serving”, but only alongside the 100g values.

I was eating some chocolate today that listed the serving size as 3 squares of chocolate. The bar is made in rows of 4 squares…

But the bar was 85g (and yes I ate the whole thing).

I thought something similar had recently been brought in in the US too, residually in light of stuff like Tic Tacs have “zero” Calories per services despite being almost 100% sugar. Please tell me I didn’t imagine that ruling from several months ago…

Because the USA counts non-starchy carbohydrates – “dietary fibre” in the carbohydrate count. Subtract the fibre from the carbs to get the metabolic carbohydrate quantity.