Your answer is informative, so I can't fault you for that, but I already know this. I asked because "empty calories" is (almost) always uttered in the same breath as either 1) no real information or 2) comparing to other carbohydrates.
I do however take issue with this:
> but once you have "enough" carbohydrates to fuel whatever activity you're doing adding more just causes your body to convert them into fat. So, that's why they're considered "emtpy"
That's true with any calorie. By that definition any calorie you're not using is empty.
Well sure, eating too much of any nutrient is not great. Think of it this way, if you just ate a bag of sugar everyday you'd have energy but be malnourished. Hence why theyre empty.
The same would be true with eating a bag of rice. Is rice empty calories?
I'll say it again: Talking about "empty calories" is in my experience always when masking a lack of real nutritional knowledge. Because when I hear it it's always comparing one sugar with another carb (eg flour), or sometimes even better comparing sugar with honey, as if that is any better.
If what you mean by "empty calories" is foods with only carbs and no proteins or fats, then I agree it could be a useful term. If you mean something else I'd like to know more about your reasoning.
From Wikipedia: "A nutrient is a component in foods that an organism uses to survive and grow. "
I'd say the primary for survival is energy. Sugars (carbs) are very high on that. There are of course secondary nutrients like eg amino acids in protein that are very important.
My opinion ultimately doesn't matter on this. I was just speaking to the saying.
That said, it is trivial to find primary items for survival if we just discuss things you would die without. Consider, water has zero calories, but you would die without it.
But your interpretation of nutrients do color your interpretation of "empty calories". Unless proven otherwise, I'll stand by that it's a useless phrase distracting from the conversation of nutrition.
It is a shortening of "empty [of nutrient providing] calories." This is pretty straight forward. If you were to eat nothing but sugar every day, you would die. Same as if you drank water, which is "empty of caloric or nutritional" content.
Are they worthless? No. They do provide caloric value. But they do not provide any nutritional value. This isn't even really at debate, is it?
I do however take issue with this:
> but once you have "enough" carbohydrates to fuel whatever activity you're doing adding more just causes your body to convert them into fat. So, that's why they're considered "emtpy"
That's true with any calorie. By that definition any calorie you're not using is empty.