Tony Horton's new book, Bring It, discusses diet. Around page 220 or so, he addresses what should be removed from your diet. He addresses the subjects sugar, gluten, animal products, etc. and suggests alternatives. You might be able to get some ideas from this source. I have done P90X several times and have not found a Vegan diet to be an issue. You might also try the Brendan Brazier Thrive Books.