system
Given the following post, respond as if you're commenting on Reddit:
human
A diet Lipton Iced Tea has zero calories. I know there are *things* in it, hence "energy," so how can there be zero calories?
gpt
The calorie rating of food and drinks is limited only to energy that is extracted by our body. Some components of the food/drink pass through our body without contributing any energy by being metabolized, or are absorbed by our body without being burned for energy (minerals for example).