Alright, this is a topic me and friends have discussed fairly recently. This is just an assumption because I dont have first hand experience with either of these things, but I think a bodybuilder/strength athlete diet would work really well in this situation. Something like 40/40/20, 40% protein, 40% carbs, 20% fat. Just sort of a basic muscle building diet- I think that could be highly effective with MMA. Of course, if one is training MMA/grappling/striking lets say 5+ times a week, or several days with multiple practices, the overall calories would need to be higher than normal.
I think it necessary to say this- you're diet is a much bigger player in how you look than the time you spend in the gym, so if success in MMA and an aesthetic physique is a goal of yours, watch your food. Hope this post helps
I heartily accept the motto, "That government is best which governs least"; and I should like to see it acted up to more rapidly and systematically.