Hard (both in difficulty and must-have) requirement: ability to exclude foods high in Vitamin K.

A lot of us are on blood thinners (anti-coagulants, anti-clotting, Coumadin/warfarin). Vitamin K is the essence of blood clotting (coagulant, thickener); high quantity or wide variation can be dangerous (first symptom: stroke). Creating an interesting diet consistently very low in Vitamin K is important. Ability to specify "Vitamin K between X and Y micrograms/day" would be very helpful.