How can mineral water have 0 calories?

Question

I understand that obviously water does not have calories, but the water we drink is not pure and contain other nutrients and minerals on it.

How can it still be 0 calories with these nutrients added? Is it really 0 calories or is the caloric content just extremely low (therefore they round it down to 0)?

In: 0

Answer 1

So it may be valuable here to define exactly what a calorie **is**. A calorie is the amount of energy it takes to heat 1 gram of water by 1 degree centigrade. When we use it in food sciences, it is specifically about usable energy in food or beverages.

(As an aside, when we talk about calories in food, we are typically discussing kilocalories – so the energy required to heat 1 kg of water by 1 degree centigrade. Not important for this argument, but worth mentioning).

Not everything that we consume can actually be used as energy. That doesn’t mean they are not important for us; it just means that we don’t use them as fuel.

Iron is a good example. Iron is a critical part of how our red blood cells can transport oxygen to our various tissues and is **absolutely** critical to our survival. However, we can’t burn iron as fuel – it is a building block, but not an energy source.

So mineral water may contain a number of things, but if those things can’t be used by the body as energy, then it has zero calories in terms of nutrition.