Well, I did a bit of searching through the forum to see if I could find my answer, and dug up this thread, which, more or less, asked the same question as I did:
Entering and making sense of Vitamin's and Minerals
Here's Fitday's response:
So if I understand this correctly, Fitday is saying that it takes the Govt. RDA percentage of a vitamin and converts it into its basic amount (i.e. 100% RDA of Vitamin C = 60mg). It then takes that basic amount and compares it to what you SHOULD be taking relative to your age and gender.
So, using the charts above, if I take 100% RDA of Vitamin C (60mg), Fitday reports back and says that this amount is actually only 67% of my PERSONAL requirement for Vit. C as a 47 y.o. male.
Ok, if I understand this correctly, I'll admit that I like the math. However, it does raise another criticism: Why isn't this explained somewhere?
I don't see anywhere on this site, or on the PC version where there's an explaination of where any of Fitday's numbers come from or how they can be best understood - heck, I don't even see a "Help" section anymore with the new design. All the above information is important, but it's taken me over two years to finally coax it out. This information should be readily available (especially if you're asking people to part with $30 for the PC version), and if it isn't, when the question is asked through "contact Fitday," a response should be forthcoming.
Fitday is a great product, and I still plan on using it, however, there is much room for improvement.
My $.02.