I've been trying to be consistent in logging my food intake daily. I notice when I put in an envelope of artificial sweetner it computes 14 calories and 4 carbs/packet. The Splenda bag says 0 calories/0 carbs.

If I come across this discrepancy on other foods, which do I go by--the FitDay values or the food label values?

Splenda isn't the same as something like 'Sweet N Low', for example... maybe that stuff has 14cal/4carbs. But I'd go by what the splenda bag tells you. Fitday doesn't have an option to enter a 'custom' food, if they don't have splenda in their system?