Can you ELI5 why water has no calories, which is also a unit of energy?
Calories are a very specific type of measuring energy, especially when used in the context of nutrition. When nutritionists say that water has 0 calories, they mean that water has no nutritional energy.
But when looking at it from a non-nutrition perspective water has calories.
When you say, “something has X calories”, it’s a shorthand of saying “something has an equivalent of X times the amount of energy that is needed to raise the temperature of 1 gram of water by 1°C.”
From a physical point of view water ALWAYS has energy (that you can express in calories) because something with mass can never have no energy.
Calories are a very specific type of measuring energy, especially when used in the context of nutrition. When nutritionists say that water has 0 calories, they mean that water has no nutritional energy.
But when looking at it from a non-nutrition perspective water has calories.
When you say, “something has X calories”, it’s a shorthand of saying “something has an equivalent of X times the amount of energy that is needed to raise the temperature of 1 gram of water by 1°C.”
From a physical point of view water ALWAYS has energy (that you can express in calories) because something with mass can never have no energy.