Marko, if a canned food (such as Evo) is 95% meat in wet form, then even if the protein % doesn't seem as high as the protein of the kibbled version, remember that it is much closer to nature's original structure and has a higher bioavailability, is easier to digest, etc. 42% protein is NOT natural or normal, it is highly concentrated, and no studies have proven the long-term effects on a pet's body yet. Raw meat protein % is averaged at 16 to 18%, the rest is moisture, vitamins, minerals, etc. Also, meat in its dry, meal form contains ash, which is not something you want to feed any animal IMO...
you could try to feed Zak some canned Evo (or other grainless canned food) at mealtimes, and bits of raw meat for snacks if he likes it. as long as the meat is fresh it won't hurt him, on the contrary. good luck!