system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does food have to be labeled "not a significant source of ___"

I knew my diet green tea wouldn't be a significant source of calories from fat or iron. I figured that would be a given. Is there a reason they have to include that label on everything? Also why not do it with everything else rather than just the limited few?
gpt
The FDA requires all food items to have nutrition labels. Certain substances are required on these labels, like fat, protein, carbs, sodium, cholesterol, Vitamins A and C, iron, and calcium (I am unsure if this is a complete list). If a food item however has no significant amount of any number of these items though they are allowed instead of listing zero to list that, it can help to save space especially if it is true of many of the required categories.