Plant-based (5)
(Other definitions for vegan that I've seen before include "One avoiding all animal-based food" , "Strict abstainer from animal products" , "Selective consumer" , "Conscientious consumer" , "One refusing animal products" .)
(Other definitions for diet that I've seen before include "Prescribed selection of foods" , "Health food - Council" , "Eat sparingly" , "Slimmer's regimen" , "Restriction of food intake" .)