Hi Holly! I wondered the same thing until someone clued me in. NS
stands for 'not specified' and NFS
is 'not further specified'. Fitday used the USDA database and those are USDA abbreviations, so that's how they ended up in Fitday.
So in your orange example:
Orange, mandarin, canned or frozen, NS as to sweetened or unsweetened; sweetened, NS as to type of sweetener
it means you didn't specifiy whether the oranges were sweetened or unsweetened, and if there were sweetened, with what. So Fitday assigns a generic calorie count, probably partway between sweetened and unsweetened. You can see that it's not very accurate, but if that's all the information you have, it's Fitday's best guess.
In your other example:
Salad dressing, low-calorie, NFS
it means Not Further Specified - if you don't have any more details, like was it creamy? Or oil based? Again, Fitday gives you its best guess based on the information you have.
It's a good idea to be as detailed as possible with Fitday and try to avoid the NS and NFS if you can. Of course, sometimes that's all the info you have (like when you're eating out) so it's the best you can do.
Hope that helps!