Protein shakes are the elixir of choice for many of the world’s legions of lycra-clad gym bunnies and flexing tin-shifters: After all, a body needs protein for the repair and recovery of muscles and tissues. But there is such a thing as too much of a good thing: Getting over 22% of dietary calories from protein, usually obtained from eggs, meat and milk, can cause hardened arteries – a condition which in turn can lead to stroke, heart failure and heart attack. That’s according to the results of tests on mice and humans done by the Pittsburgh School of Medicine and published in the journal Natu…