If I drank a mixture of 2 scoops whey protein + water would that work for the thermal effect and keep my metabolism up? Or does it only apply to solid food? I wouldn't mind substituting a meal from a "shake", but I am unsure if it would give me the same metabolic effects as eating...because, well, isn't the point of eating 5-6 meals a day to take advantage of the metabolic effects?

I count my whey protein shake as one of my meals everyday.