They say "no pain, no gain" – but in terms of muscle tissue, it should be "no pain + no protein, no gain". Yep, working out brakes down your muscle tissue and if don't follow up with the right post-workout nutrition, you'll be left with little to no results. For a simple guide on how to eat after a workout, check out this post. If you are already familiar with the basics, then let's take a closer look at Casein Protein. What is it – and is it necessary?