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
Yeah during pre-fight training periods and even high normal training periods training 5-6 days a week the calorie intake has to be really high. I know for myself personally I burn a little over 2000 calories resting and with exercise it is around 6-8k so I have to keep my intake around 9-10k to gain mass and not feel hungry all the time. Calorie intake this high while keeping fat intake low and protein and carbohydrate intake high is extremely difficult when wanting to keep body fat down around 8-10% and sometimes lower depending on the build and desired weight of the particular person.