I agree with Stryc-9. DNP is not something to be taken lightly. And judging by some of your other threads on the diet board (e.g. taking meth for weight loss), it sounds like you are going to the extreme.
It also seems you haven't researched DNP thoroughly, since you are asking basic questions about benadryl.
What other supps have you planned on taking with the DNP? Are you even prepared for it?
If you do decide to go through with it, keep in mind that you shouldn't eat junk; a clean diet is very important, otherwise you are defeating the purpose.
Anyway, I sincerely suggest you post up your current diet, workout routine and supps. I am sure there are changes that could be made, that will give you results.