I am on a high protein diet myself and it sucks ass in the beginning.
40 grams of protein seems to be a lot every 4-5 hours, roughly that would require a hour of exercise 3-4 times a day, I dont know how long Soulfly exercises but that seems a lot.
I use a WHEY protein supplement amongst other things. Pretty much a simple rule (don't hold me to it) is that a piece of meat thats is 250-300 grams uncooked has around 35-40 grams of protein.
Now I am training 4 times a day which works out to be like 5-6 hours depending, now pretty much you want to have protein after every time you train to see results also if you want to get big eat carbs (dont eat much if you want to lose lol). Carbs good source of energy but builds bulk/mass.
Kust