Using 4, 4, and 9 to calculate calories is a great rule of thumb but is not nearly accurate enough. (Some nutritionists recommend 4, 4, and 8 - which, in your example, would yield a number much closer to FitDay: 1668.) Either way, I would not trust a calculation that relies on 1 significant figure.
That being said, FitDay does not calculate calories at all. Each value in a food's nutrition information is stored separately in the database. No nutritional value is determined from a calculation that involves other nutritional values (excluding "Calories from Fat"). If you log a food that comes from our database, that information comes directly from the USDA. Custom foods are entered manually and FitDay does not alter those values.
FitDay only adjusts RDA and DV calculations which are determined based on the users age and gender.
Last edited by IBswilson; 06-08-2012 at 04:09 PM.