Is your basis for this claim anecdotal? Do you know that the effects aren't down to avoiding the "junky" foods as opposed to the powder's themselves?
The only superior diet in my long quest for excellence is a regular juice diet, which is either incredibly labor intensive or very expensive (much more than the pricey green powder.)
The (fresh) juice (greens and roots, less fruit) diet made me feel amazing yet impossible to keep on mass.