For the past few years I have been anti steady state cardio and all about HIIT
(high intensity interval training). 
My current plan goes against everything I have believed and practiced and has me doing five 45 min sessions of steady state cardio per week! It’s eating at my core and I just want to sprint! Instead of questioning my trainer I did some research and found this great article. Steady state does have its place depending on your goals.   

I’m training hard with weights and on a calorie deficit. Adding intense cardio would likely result in muscle loss and not gain.  My goal is to maintain my muscle while losing fat. It’s a slow process with many different variables. Cardio is one of them and this article helped me better understand why I have to spend so much time doing cardio vs 15 minute intervals. 

http://www.bodybuilding.com/fun/going-steady-5-reasons-to-do-steady-state-cardio.html