Hmmm, well it certainly looks like a "diet" to me! I am not too keen on plans that restrict whole food groups and this certainly does. There are little to no carbs in there to assist you in the cardio exercise you are undertaking.
Usually high protein, low carb diets (combined with your kind of exercise) are for athletes, bodybuilders etc....or so my gym friends tell me...
However, I presume you will still lose weight as diet plans like Atkins use similar principles.
I am a firm believer in still eating everything! (yep including cake/chocolate lol) but in moderation. Restrictive diets are hard to follow forever.