Evolution exists and we can see it even in our lifetime. Look at the people in the 50s of the last century and present-day people. Now the youth grows and they are much higher. Children start to sit and walk faster. All this is an example of evolution on a short stage.
People like you are the reason why I, coming from atheist family, found God late in my life.
You are referring to Flynn effect, not fucking evolution theory! Better nutrition and healthcare has nothing do with genetic drift and variation or even formation of different species.
http://www.unz.com/isteve/the-flynn-effect-for-height/And you know what? It is fully reversible. Early modern humans being significantly smaller, than their stone age ancestors both in height, brain size and muscle mass. Due to lifestyle, not genes.