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:
Originally Posted by fitday_jim
Hi funrun73. That is a great question and it confuses lots of people.
Essentially there is confusion around the "Daily Values" found on food labels and the RDA graphs in FitDay. The US government uses Daily Values for the values on a food label. These values are picked by the government to be useful without knowing the person's age and gender. FitDay takes those numbers and turns them into an amount ( for example 100% of Vitamin C becomes 60mg).
FitDay displays RDA charts in our reports.Your RDA for a nutrient is a different government standard that takes into account things like your age and gender. These are things that the label couldn't take into account. So while the DV was 100%, your personal RDA may be 110% because you need less due to your age and gender.
This can be confusing, but I hope this helps
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.